posted 02-24-2014 05:29 PM ET (US)        

I have investigated the ratio of power output as a function of engine displacement for several types and brands of outboard engine. The engines selected are from the standard product lines. I avoided engines which were indicated as being special models with extra power, such as the Evinrude High-Output engines. I used the cowling horsepower as the power output. I used the manufacturer's stated displacement for the displacement. The data is shown in a PDF document (linked below).

In the Evinrude E-TEC series, the engines studied were in five displacements:

--1.295-liter in-line three-cylinder
--1.726-liter V-block four-cylinder
--2.592-liter V-block six-cylinder
--3.279-liter V-block six-cylinder
--3.441-liter V-block six-cylinder

The power output ranged from 70-HP to 300-HP. The average power output per liter of displacement for this group was 67.6-HP/liter. The 90-HP, 115-HP, 175-HP, and 225-HP models were all very close to this average, deviating by only a few percent. The 70-HP, 150-HP, and 200-HP models were all below average, that is, they made less power per liter than average, by ten to twenty percent less. The 250-HP and 300-HP models made more power per liter than average by 12-percent and 29-percent.

In the Mercury FOURSTROKE series, the engines studied had only two displacements:

--1.7-liter in-line four-cylinder
--3.0-liter in-line four-cylinder

The power output ranged from 75-HP to 150-HP. The average power output per liter of displacement for this group was 54.9-HP/liter. All models tended to be below the average except the 115-HP, which was quite an outlier in the data, being 23-percent above the average.

The Yamaha engines were studied in two groups: a conventional engine group and the new Offshore engines.

The Yamaha conventional engines studied were in five displacements:

--1.7-liter in-line four-cylinder
--1.832-liter in-line four-cylinder
--2.67-liter in-line four-cylinder
--2.785-liter in-line four-cylinder
--3.352-liter V-block six-cylinder

The power output ranged from 75-HP to 250-HP. The average power output per liter of displacement for this group was 62-HP/liter. The 115-HP, 175-HP, and 200-HP models were closest to the average. The 75-HP and 250-HP were farthest from the average, being about 24-percent below and 20-percent above, respectively.

The Yamaha Offshore engines were in only one displacement, 4.2-liters. The power output ranged from 225-HP to 300-HP. The average power output per liter of displacement was 61.5-HP/liter. The 250-HP model was closest to the average power per liter of displacement.

The Suzuki engines studied were in five displacements:

--1.496-liter in-line four-cylinder
--2.044-liter in-line four-cylinder
--2.867-liter in-line four-cylinder
--3.614-liter V-block six-cylinder
--4.028-liter V-block six-cylinder

The power output ranged from 70-HP to 300-HP. The average power output per liter of displacement for this group was 60.7-HP/liter. The 90-HP, 175-HP, 225-HP, and 250-HP (4-liter) models were closest to the average, with just a percent or two variation. The 70-HP and 300-HP models were farthest from the average, being about 23-percent below and 23-percent above, respectively.

The Honda engines studied were in four displacements:

--1.496-liter in-line four-cylinder
--2.354-liter in-line four-cylinder
--3.471-liter V-block six-cylinder
--3.583-liter V-block six-cylinder

The power output ranged from 70-HP to 250-HP. The average power output per liter of displacement for this group was 59.3-HP/liter. The 90-HP, 135-HP, and 200-HP models were closest to the average, with just few percent deviation. The 70-HP and 250-HP models were farthest from the average, being 21-percent below and 18-percent above, respectively.

ANALYSIS

The data shows that among the four-stroke power-cycle engines, the Yamaha, Suzuki, and Honda engines have remarkable consistency in average power output per liter of displacement. Those engines average around 60-HP per liter of displacement. The Mercury engines studied are significantly lower in power output per liter of displacement, averaging about 54-HP/Liter. This difference in power output per liter of displacement between these two groups is easily explained. The Yamaha, Suzuki, and Honda engines all employ modern methods of enhancement of power output such as:

--multiple valves per cylinder
--multiple cam shafts
--variation in valve timing over the engine speed range, called cam phasing or variable valve timing
--variation in valve lift or opening; part of the cam phasing system
--electronic tuning of input air flow paths
--knock sensor to control and compensate for pre-ignition
--oxygen sensor to control fuel:air mix ratio

In contrast, the Mercury engines studied make no mention of any enhancement of these types. This difference most likely accounts for the lower power output per liter of displacement of the Mercury engines compared to the Yamaha, Suzuki, and Honda engines.

The E-TEC engines averaged about 67-HP per liter of displacement power output, about ten-percent more than the four-stroke-power-cycle group of Yamaha, Suzuki, and Honda, and about 20-percent more than the Mercury group. The 300-HP E-TEC had 87.2-HP per liter of power output, by far the most of any engine studied.

The collected data is presented in

posted 02-24-2014 06:48 PM ET (US)         

Seems like cherry picking to make some sort of point. You keep referring to some technology as "modern" differentiating from your target technology "large-displacement".

Lets look at your list of "modern" technology:

--multiple valves per cylinder : 1912
--multiple cam shafts: 1912
--variable valve timing: 1920's
--tuning of input air flow paths: 1960's if not earlier
--knock sensor: 1982
--oxygen sensor: 1970's

Half of these technologies pre-date the 1930's, which was the date given for large displacement technology by jimh, all of these technologies are more than three decades old.

posted 02-24-2014 07:17 PM ET (US)            

Having said that, I do really like my 135 Verado.

posted 02-24-2014 08:22 PM ET (US)         

quote:

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Seems like cherry picking to make some sort of point.

---

I thought the same thing, but assumed jimh was only wanting to consider naturally aspirated engines.

So, why not look at Optimax engines.

3.0L optimax engines range in HP/L levels of 76 to 83 for both regular and ProXS varieties.
1.5L optimax engines range in HP/L levels of 50 to 83 for both regular and ProXS varieties.
2.6L optimax engines range in HP/L levels of 60 to 70.

posted 02-24-2014 10:00 PM ET (US)         

quote:

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I believe the Verado engines are High Output which were not included in the report.

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Then what are the "Pro Fourstroke" family of engines? The Verados seem to be marketed as the "Normal Output" engines at least in the 175-300hp range. Of course I am sure one could use some tortured logic to lump them into a HO strawman in order to exclude them from the running.

It could have been specified that only NA engines be allowed to participate, but why? Just more arbitrary cherry picking, I say two-strokes not be allowed, they have no more right to be in this group than a boosted engine. What is one trying to prove by singling out certain engine design approaches?

posted 02-24-2014 11:33 PM ET (US)            

jharrell--I did not include the VERADO engines because they use supercharging. In a supercharged engine you can more or less dial up the power desired by adjusting the boost. There are only two displacement sizes in the VERADO family, covering a very wide range of power output level.

I do not consider omission of the VERADO to constitute an oddity.

The data was not "cherry picked." I created the spread sheet, collected the data scraping it off the websites of the manufacturers, and computed some new data from the collected data. I had no idea what the data would reveal until after I collected it and looked at the outcome. At no point was any data deleted from the set of engines because I found it was not compliant with a prior point of view.

(Actually, I very carefully checked the spreadsheet to make sure it was accurately computing the data after I found a glitch had crept into my formula for some cells. So I did study the data for non-conforming results, but only to the extent that the calculations were in error.)

If you want to add other engines to the data, you are welcome to collect the data, compute more values, and add it to the results.

There is no reference made by me to "1930" in this article. I do not understand what 1930 has to do in the context of this data. Please explain how 1930 affects the data or the calculations made from the data. As far as I can tell, 1930 has no bearing on any of this data. All the data comes from 2014 and all the calculations were made in 2014.

posted 02-24-2014 11:51 PM ET (US)            

I don't think it is reasonable to make a case against my suggestion that the reason the Yamaha, Suzuki, and Honda engines make more power per liter than the Mercury engines is related to and probably caused by the use of the several power enhancing technologies I list as appearing on the Yamaha, Suzuki, and Honda engines which are absent from the Mercury engines. I think that is a very reasonable conclusion and is supported completely by the data.

posted 02-25-2014 12:07 AM ET (US)            

The oldest four-stroke-power-cycle outboard engine that I know is the Homelite or Boston Whaler BEARCAT, which was produced in the early 1960's, or about 50-years ago. The BEARCAT engine has about the same level of power enhancement as the Mercury FOURSTROKE engines, that is, it has none of those power enhancing features.

The BEARCAT engine made 55-HP at the power head. I suspect at the propeller it probably made 50-HP. It had a displacement of 59.4-cubic inches, or 0.973-liter. That is a power output of 51.4-HP/Liter. That puts the fifty-year-old BEARCAT into the same level of power output per liter as the 2014 Mercury FOURSTROKE.

For more about the BEARCAT engine, see my lengthy and detailed historical account of its evolution at

posted 02-25-2014 12:29 AM ET (US)            

It is possible to produce more power per liter of displacement if the engine speed is allowed to increase. A good example of this can be found in the Bombardier ROTAX E-TEC two-stroke-power-cycle engine used on their snow machines. This 0.8-liter two-stroke engine uses E-TEC technology and produces 164-HP. That is a power output of 205-HP per liter, which is a staggering figure and much greater than any of the outboard engines in this survey. The ROTAX E-TEC runs at over 8,000-RPM. It also uses a method of tuning the engine ports which is akin to cam phasing in the four-stroke, and this helps improve the power output.

posted 02-25-2014 08:19 AM ET (US)         

In the Optimax models available under Mercury's standard badging, the plain Optimax 200 and 250 HP models have the same HP/L ratio as the ProXS models, so it is reasonable to assume that the additional ProXS models (225 HP - 115 HP) would also contain the same ratios.

posted 02-25-2014 11:55 AM ET (US)            

As far as the OptiMax being neglected in my survey, I will say that among reports of re-powering of Boston Whaler boats, there is little mention of the OptiMax as being a popular choice. Boston Whaler has not been offering an OptiMax on their new boats for about a decade.

As for the Verado being neglected in my survey, I will say that among reports of re-powering of Boston Whaler boats there is practically no mention at all of Verado being used. I can think of perhaps one or two instances in the last decade in which a Verado was selected for re-power of a Boston Whaler boat that did not already have a Verado.

Most all of the talk about re-power has been about the Yamaha, Honda, Suzuki, and Mercury four-stroke-power-cycle engines (excluding the Verado) or about the two-stroke-power-cycle engines of E-TEC. In this regard I believe the original engines I selected in for the survey are representative of the majority of the interest.

posted 02-25-2014 12:20 PM ET (US)            

In the Mercury OptiMax series, the engines studied were in three displacements:

--1.5-liter in-line three-cylinder
--2.5-liter V-block six-cylinder
--3.0-liter V-block six-cylinder

The power output ranged from 75-HP to 250-HP. The average power output per liter of displacement for this group was 69.4-HP/liter. Only the 175-HP model was very close to this average, deviating by only one percent. The 75-HP, 90-HP, 150-HP, and 200-HP models were all below average, that is, they made less power per liter than average, by four to 28-percent less. The 115-HP, 125-HP, 225-HP, and 250-HP models made more power per liter than average, ranging from eight to 20-percent above the average.

(I included two models from the OptiMax Pro XS models to have a better spread of power. For some reason, Mercury only makes the 175-HP and 225-HP engines in the Pro XS model. Repeated mentions in this discussion assure readers that there is no difference between OptiMax and OptiMax Pro XS except cowling graphics.)

In the Mercury Verado series, the engines studied were in two displacements:

--1.7-liter in-line four-cylinder
--2.6-liter in-line six-cylinder

The power output ranged from 150-HP to 300-HP. The average power output per liter of displacement for this group was 101.2-HP/Liter, by far the highest average of any group. Only the 175-HP model came close to the average. All other models were either above or below average; the range was from minus 14-percent to plus 16-percent. This is not unexpected. With a supercharged engine the power output is very dependent on boost pressure. Changing boost pressure limits permits engines of many power levels to be made from a common displacement.

ANALYSIS

Comparing the OptiMax and E-TEC, the two-stroke-power-cycle direct-injection engines, we see they average about the same power per liter at 69.4 and 67.6-HP/liter, respectively.

posted 02-25-2014 02:09 PM ET (US)            

With a supercharged engine the power output is very dependent on boast pressure.

I corrected this to

With a supercharged engine the power output is very dependent on boost pressure.

That made me think I might be on to something, and suggested a corollary:

With a non-supercharged engine the power output is very dependent on boast pressure (that is, the boasts made about the power output by its fan club members).

posted 02-25-2014 03:20 PM ET (US)         

90 1.726 52.14368482
135 2.589 52.14368482
150 2.589 57.93742758
200 3.279 60.99420555
225 3.279 68.61848124
250 3.441 72.65329846
Average 60.74846375

Interesting, the HO engines have a lower average HP/liter than their normal counter parts.

ANALYSIS

Both Evinrude and Mercury utilize a lower HP/liter ratio in order to achieve higher performance.

I think it would have been wise for Mercury to label their Fourstroke series as "High Output", it may have avoided the criticism of the moderator since it would have automatically excluded them from analysis.

posted 02-25-2014 03:54 PM ET (US)            

- Direct injected two-strokes, regardless of brand, put out approximately equivalent horsepower per unit of displacement;

- "Higher-Tech" four-strokes, regardless of brand, put out slightly more horsepower per unit of displacement than less complicated four-strokes; and,

- Super-charged four-strokes put out substantially more horsepower per unit of displacement than naturally aspirated four-strokes.

WOW! I never would have guessed.

posted 02-25-2014 03:57 PM ET (US)         

quote:

---

As far as the OptiMax being neglected in my survey, I will say that among reports of re-powering of Boston Whaler boats, there is little mention of the OptiMax as being a popular choice. Boston Whaler has not been offering an OptiMax on their new boats for about a decade.

As for the Verado being neglected in my survey, I will say that among reports of re-powering of Boston Whaler boats there is practically no mention at all of Verado being used. I can think of perhaps one or two instances in the last decade in which a Verado was selected for re-power of a Boston Whaler boat that did not already have a Verado.

---

I suppose we can infer that the articles purpose was to provide data, perhaps to aide in the selection of an appropriate engine with which to re-power a classic Boston Whaler. Since the stated purpose of the article was omitted, it was reasonable to assume the data was presented for some other purpose.

Having said that, I'm not sure the HP/L ratio of an outboard engine is on the minds of most people when choosing a suitable replacement engine.

posted 02-25-2014 06:28 PM ET (US)            

The data is open to any interpretation anyone would like to offer. The advantage of having this data in a single place, organized in a easily read form, is just that the data is in a single place and is organized. I did not invent the data or make it up. There is no speculation in the data. The data is all data from the manufacturers. Everyone is welcome to take the data and use for whatever purpose they like.

posted 02-25-2014 06:31 PM ET (US)            

quote:

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So let me see if I understand all of this . . .
- Direct injected two-strokes, regardless of brand, put out approximately equivalent horsepower per unit of displacement;

- "Higher-Tech" four-strokes, regardless of brand, put out slightly more horsepower per unit of displacement than less complicated four-strokes; and,

- Super-charged four-strokes put out substantially more horsepower per unit of displacement than naturally aspirated four-strokes.

---

posted 02-25-2014 06:36 PM ET (US)            

quote:

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As long as you have a spreadsheet, why not add HP vs. weight calculations?

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In many cases the engine weight is not changed much over a wide range of horsepower, and it is more or less proportional to the horsepower as a function of displacement.

posted 02-25-2014 06:49 PM ET (US)            

In the case where TransAm invented horsepower ratings for the E-TEC H.O. engines, the calculation of HP/LITER shows that the engines are conservatively rated by TransAm for power, since they tend to fall below the average of the other E-TEC engines. This leads to two possible conclusions:

--the horsepower invented by TransAm was incorrect, or

--if the horsepower invented by TransAm was correct, the H.O. engines are anything but high-output.

posted 02-25-2014 07:05 PM ET (US)            

quote:

---

I'm not sure the HP/L ratio of an outboard engine is on the minds of most people when choosing a suitable replacement engine.

---

I don't have any data on what is on the mind of outboard engine buyers, so I cannot offer any advice on your speculation about what outboard engine buyers are thinking about when choosing an engine.

It never occurred to me that before gathering this data, organizing the data, and calculating a few simple measures of the data, I should first have taken a survey about what was on the mind of people who are about to buy a new outboard engine.

Actually, I think Evinrude has already taken that survey. They undertook a study of what was important to buyers of outboard engines before they began to develop their E-TEC engines. According to reports on Evinrude's survey--I do not have the actual survey results on hand, but just a report of what those results were--the buyer of a new outboard would look at an engine as follows:

(Excerpt from E-TEC White Paper published in c.2002)

quote:

---

Outboard consumer surveys, conducted around the world in
2001, were commissioned to gauge if the typical outboard
owner’s requirements had changed. The results were a little
surprising to many of the older marine engineers. In order of
preference, the modern outboard owner wanted:

1. DQR - Dependability, Quality and Reliability

2. Ease of Maintenance

3. Easy starting

4. Performance

5. Economy

6. Style/appearance

---

I would make the inference that power output as a function of displacement is probably related to item four, Performance, and also perhaps to item one, Dependability, Quality, and Reliability.

In any case, I don't have any way to measure the interest of a new outboard engine buyer in the power output as a function of displacement, and I have not tried to make any measurement of it. So I cannot really offer any informed sort of comment on where exactly it would be on the mind of a new engine buyer.

If you will notice, I have only made one conclusion that is not actually a hard fact. I concluded that it was likely that the reason the Mercury FOURSTROKE engines did not produce as much power on average as the Yamaha, Suzuki, and Honda engines was likely due to the significant difference in the use of power-enhacing refinements. (See my list above of power enhancing refinements.)

posted 02-25-2014 07:17 PM ET (US)            

I did not realize that this topic was forbidden or taboo to so many readers.

Next, I found it even more incongruous that some readers would insist I must include the OptiMax and Verado engines from Mercury in the survey. When I did that, it just accentuated the gap between the power output from the Mercury FOURSTROKE engines and all other competitors.

posted 02-25-2014 07:36 PM ET (US)         

jimh writes:

quote:

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In the case where TransAm invented horsepower ratings for the E-TEC H.O. engines, the calculation of HP/LITER shows that the engines are conservatively rated by TransAm for power, since they tend to fall below the average of the other E-TEC engines. This leads to two possible conclusions:

--the horsepower invented by TransAm was incorrect, or

--if the horsepower invented by TransAm was correct, the H.O. engines are anything but high-output.

In considering the first case, I will apply the same principle of outrageous suspicion that have been used by critics of my data: it is clearly a case of TransAm inventing data in order to fulfill some agenda. In this case, TransAm invents data for the survey. It is impossible to make this same charge against me, so I consider that proof of TransAm's bias and clear intent to make the survey results fit his agenda. On the other hand, I invented no data, so I cannot be accused of having any bias in the data.

---

I have read, and re-read every work I have posted in this article and aside from this post, have not introduced Evinrude Etec engines as a topic of discussion. I would ask that you correct the narrative to reflect as such.

posted 02-25-2014 07:43 PM ET (US)         

quote:

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The basis of the survey is that the survey gets data from the manufacturers and does not invent data. The Evinrude H.O. engines are not rated for horsepower. Therefore, it is not possible to include them in this analysis.

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I did not invent the data it came right from Evinrude's catalog where each HO engine has a clearly stated horsepower rating. The catalog can be found here: http://www.evinrude.com/Content/Pdf/en-US/2014_Evinrude_Catalog.pdf

Page 43 there is a row labeled horsepower. They denote each number with an H.O., perhaps you are trying to invent some new power unit called power H.O., Evinrude however seems to think of that number as the horsepower.

The reference the cowling number as horsepower again in the engine comparison tool. I would be silly to compare engine horsepower if they weren't in fact rated for horsepower.

posted 02-25-2014 09:53 PM ET (US)         

jimh suggests:

quote:

---

In the case where TransAm invented horsepower ratings for the E-TEC H.O. engines, the calculation of HP/LITER shows that the engines are conservatively rated by TransAm for power, since they tend to fall below the average of the other E-TEC engines. This leads to two possible conclusions:

--the horsepower invented by TransAm was incorrect, or

--if the horsepower invented by TransAm was correct, the H.O. engines are anything but high-output

---

So, we can deduce the horsepower invented by TransAm (I think he means referenced from Evinrude literature, by jharrell) was not incorrect.

and,

posted 02-25-2014 10:14 PM ET (US)            

quote:

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[The addition of the Verado and Optimax data] just accentuated the gap between the power output from the Mercury FOURSTROKE engines and all other competitors."

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Your "analysis" does not show any gap whatsoever in the between the power output of the Mercury FourStroke 150 and any other 150 horsepower motor. They all put out 150 horsepower. I don't know anybody who has or would purchase an outboard motor based on horsepower per unit of displacement.

posted 02-25-2014 10:30 PM ET (US)            

AVG = average.
FM = from
% = percent sign

Let me give you some pointers to references for those:

http://dictionary.reference.com/browse/avg
http://dictionary.reference.com/abbreviations/fm
http://www.reference.com/browse/percent%20sign

They are all in common use and found in many references.

As for the "PRO XS" in OptiMax Pro XS, I am not sure what that means, but my best guess is the "PRO" does not mean professional, because that engine is sold to non-professionals, and the "XS" does not mean eXtra-Short, because the shaft length is not less than 15-inches. I think it is some sort of branding. In any case, I did not make that up, either.

posted 02-25-2014 10:49 PM ET (US)            

Well, I already mentioned the revelation in the data about the close correspondence in HP/LITER measurements of the Yamaha, Suzuki, and Honda engines. Prior to gathering the data, I had no idea that the three makers had engines that followed such a similar pattern. I had not previously looked very closely at this data or analyzed it in a consistent manner, so when I carried out the simple calculations, I was surprised that the three brands were so similar.

I was anticipating that the Mercury FOURSTROKE engine would need more displacement to make their horsepower, but the difference was something of a surprise, too. The Mercury FOURSTOKE engine are only ten-percent behind the other four-strokes. This was less than I expected. My expectations were based on the many comments I had read previously about these engines having large displacement. I was, therefore, expecting them to make less power per liter, but I think the difference is not as much as I was led to expect.

After I was badgered about not including the Verado and went to the trouble of gather that data to appease the hordes, I learned a few things from that data, too. I was very surprised that the 200-HP Verado was the model that was cranking out the most power per liter, at 117.6-HP per liter. The 200-HP is running harder than even the 300-HP. I would have never guessed.

In the E-TEC line I was surprised how much consistency there was in each displacement with one of the models hitting right at the average power. As I already mentioned, the 115, 175, and 225 all produce just about exactly the same amount of power per liter and that is also the average power-per-liter for the family, which suggest to me that those three are all tuned or programmed the same, with displacement being the variable.

In the Yamaha line, I was surprised there were so many different displacements in their engines. I had no idea they made six different displacement engines in their line from 75 to 250-HP. I think that is the most diversity of displacement in one brand.

posted 02-25-2014 10:57 PM ET (US)            

quote:

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I thought FM was a common abbreviation for frequency modulation.

---

posted 02-25-2014 11:14 PM ET (US)            

My apologies for mixing your comments together and attributing them to the wrong person.

Re the horsepower of the E-TEC engines marked H.O.:

As I mentioned, I used the websites as the source. If you go to the Evinrude website and look up an E-TEC H.O., there is no horsepower listed. For example, visit:

http://www.evinrude.com/en-US/engines/ETEC_HO/ETEC_250_HO

In the specification tab, the following entry appears:

Propshaft horsepower: Factory tuned for high performance

This is Evinrude's stance, and it has been that way for many years. That is why I have not included the H.O. engines.

If you make an arbitrary decision that a particular engine makes a particular horsepower, you are affecting the data. I did not want to affect the data. Therefore I did not decide what horsepower the 250 H.O. makes. I just did not include them in the survey because it would be inconsistent for me to just invent a power for each of them.

posted 02-25-2014 11:23 PM ET (US)            

quote:

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Thanks Jim. I think that is good advice. You might employ that strategy the next time somebody poses a question or comment about their 22 OR instead of laboriously dragging out your tiresome brackets.

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Tom--you should get used to it because I am not changing. The "OR" is particularly troubling as it is a common word (or) and in searching algorithms is either a reserved word or is ignored. Try searching for information about an OUTRAGE by searching for "OR" and you will see the problem.

posted 02-25-2014 11:43 PM ET (US)            

If a 200-HP Verado is making 200-HP at the propeller shaft, that means that the engine was probably making 200/0.9 or 222-HP. It used 22.2-HP to run the supercharger, leaving 200-HP for the useful output. If you look at the power output per liter with that in mind, the Verado is averaging even more horsepower per liter than the data shows.

And, yes, I know all the engines make more power at the crankshaft than at the propeller shaft, but we have been ignoring it. The Verado is unique in that is has a supercharger creating extra load.

The OptiMax engines have a similar situation because they have to drive an air compressor, but I don't think the air compressor load is as high. It probably only takes less than 5-HP to drive the air compressor on a 200-HP OptiMax.

posted 02-25-2014 11:46 PM ET (US)            

quote:

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By the way, I'm in the "The simpler, the better" camp. I think that a motor that uses higher displacement rather than adding a bunch of complex systems to attain a certain horsepower rating will eventually prove to be more reliable and (or) more economical in the long run, especially if it's not pushing the ragged-edge of squeezing every last bit of horsepower out of a given amount of displacement.

---

posted 02-26-2014 08:02 AM ET (US)         

quote:

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In the specification tab, the following entry appears:

Propshaft horsepower: Factory tuned for high performance

---

Except everywhere else including their catalog they have a listed horsepower, including where it legally counts: The EPA.

Also the 90 HO lists a horsepower on the spec page, can it now be included since it satisfies your arbitrary goal post?

If they are not rated for horsepower, how did they get an EPA certification?

For something to be "High Output" it's output has to be higher than something else correct? What is the 90 HO higher output than, a 300 hp motor or a 15 hp motor? Or could it possibly be it's higher than their "normal" 90? Thats my guess. How did they accomplish this higher output? More displacement, wow just like Mercury.

There is a simple reason why the HO was not included, it contradicts your desired result and was therefore eliminated.

quote:

---

If a more strict comparison were to be made, it would have to consider the parasitic losses in the Verado supercharger and OptiMax air compressor which are not present in the other engines when looking at the power generated by the engine per liter of displacement.

---

Again singling out Mercury. Both the Optimax and E-TEC must inject fuel into the combustion chamber under high pressure. To create this pressure, energy must be used, this energy must come from somewhere. In the case of the Optimax, it is a belt from the crank, in the case of the E-TEC it is electrictricity created from a alternator on the crank. Pressure is pressure, the energy must be used to create it and must come from somewhere, whats more efficient a belt or alternator-voice coil? Do you have data on this?

posted 02-26-2014 08:43 AM ET (US)            

quote:

---

There is a simple reason why the HO was not included, it contradicts your desired result and was therefore eliminated.

---

That is wrong. It was not my intent. And it does not contradict anything. I think you are reading too much into this.

He also ponders:

quote:

---

Again singling out Mercury. Both the Optimax and E-TEC must inject fuel into the combustion chamber under high pressure. To create this pressure, energy must be used, this energy must come from somewhere. In the case of the Optimax, it is a belt from the crank, in the case of the E-TEC it is electrictricity created from a alternator on the crank. Pressure is pressure, the energy must be used to create it and must come from somewhere, whats more efficient a belt or alternator-voice coil? Do you have data on this?

---

We can get a good idea of the electrical power from the relationship

1-HP = 0.746-kW

The alternator on these engines generates the electrical power. In order to have 22.2-HP of loss (the estimate for the supercharger) we would need

22.2-HP x 0.746-kW/1-HP = 16.56-kW of electrical power

At 12-Volts that would mean 1,380-Amperes

The E-TEC has a nice alternator, but it only is able to generate about one-tenth that amount of current. It is impossible that the electrical energy needed by the voice-coil injectors is anywhere close to the mechanical energy of the supercharger.

Also, you forget that the OptiMax has twice as many injectors as the E-TEC, so it is reasonable to conclude it consumes twice as much electrical energy operating those injectors.

Finally, the voice-coil injector of the E-TEC uses a sort of dynamic braking technique in which the movement of the injector piece in the magnetic field of the coil actually generates electrical energy. This is part of the patent of the technology. So the E-TEC injector actually generates electrical energy in its operation. This further reduces its net electrical load.

In summary, I find the electrical load of operating an E-TEC injector is not equivalent--not even close--to the mechanical load of running the supercharger of a Verado.

jharrel also observes

quote:

---

...a supercharger robs power, so do cams, electronics, injectors, bearings, valves.

---

I agree, in part. In the engines with a lot of additional mechanical components in motion, such as the balance shafts, more cam shafts, transfer shafts, and so on, there is an opportunity for added mechanical loss. In addition, all of that moving mass retards acceleration, making the engine response slower. But I do not see much difference among the engines in the survey in the electrical loads from the electronics. I don't think there is much difference in the electrical power used for their control units. As for the electrical load of the injectors, see my comments above.

posted 02-26-2014 09:10 AM ET (US)            

quote:

---

There is nothing wrong with this method. It has been proven to work over the last 85-years. It is really an old-fashioned and proven way to get more power from an engine: increase its displacement.

---

Perhaps some people are offended by the characterization of the method of increasing power by increasing displacement as being old fashioned. I am afraid I cannot be held accountable for the time frame when this method was first used. It has been used for a long time, and particularly in outboard engines, which have tended to remain simple in their design until relatively recently.

posted 02-26-2014 10:15 AM ET (US)            

This description is generally interpreted to mean the engines make more horsepower than other engines with the same numbers in the cowling decal. For example, a 200 H.O. is presumed to make more power than a 200-HP model. This is acknowledged by jharrel when he writes:

quote:

---

For something to be "High Output" [its] output has to be higher than something else....What is the 90 HO higher output than, a 300 hp [engine] or a 15 hp [engine]? Or could it possibly be it's higher than their "normal" 90? That [is] my guess

---

I agree. Your interpretation is the same as mine. I believe the Evinrude models designated as H.O. models produce more power output than the standard models. I have no idea what their exact power output might be.

posted 02-26-2014 02:48 PM ET (US)         

quote:

---

The alternator on these engines generates the electrical power. In order to have 22.2-HP of loss (the estimate for the supercharger) we would need

22.2-HP x 0.746-kW/1-HP = 16.56-kW of electrical
power

---

Why are you comparing this to a supercharger? My comparison was specifically to the Optimax fuel injection pump, comparing parasitic losses of fuel injectors to superchargers makes no sense and only obfuscates the data. Stop playing games.

quote:

---

At 12-Volts that would mean 1,380-Amperes

The E-TEC has a nice alternator, but it only is able to generate about one-tenth that amount of current.

---

quote:

---

but I don't think the air compressor load is as high. It probably only takes less than 5-HP to drive the air compressor on a 200-HP OptiMax.

---

Again very strange comparisons made when the author has more accurate information, I simply don't understand the logic.

My understanding was that the E-TEC has a 55 volt alternator to supply power to the fuel injection system. I would imagine this is do to the large power requirements of the system. At 55 volts only about 60 amps would be required to generate less-than 5hp, although I doubt the optimax air pump uses anywhere near 5hp, nor does the E-TEC require 60 amps continuous. Was there some source for the 5hp figure? My understanding is the Orbital system uses about 6 CFM of air at 90psi this works out to less than a one horsepower needed to create the pressure.

quote:

---

Also, you forget that the OptiMax has twice as many injectors as the E-TEC, so it is reasonable to conclude it consumes twice as much electrical energy operating those injectors.

---

No not reasonable in the least. You also forget the Orbital system is considered "low pressure" relative to other direct injections systems. It runs at 90 psi rather than the E-TEC's 700 psi. It take less power to increase to 90 rather than to 700, quite a bit less, this is simple physics.

Also you forget one injector is a standard automotive type low pressure injector driven by medium pressure rail using 12v. The second high pressure injector is driven by the air compressor. The E-TEC also has a medium pressure rail feeding the high pressure unit injectors from a similar 12v electric fuel pump. Therefore the the system should be quite comparable as far as power usage goes and just the primary high power injectors and their power source can be compared for losses.

quote:

---

Finally, the voice-coil injector of the E-TEC uses a sort of dynamic braking technique in which the movement of the injector piece in the magnetic field of the coil actually generates electrical energy. This is part of the patent of the technology. So the E-TEC injector actually generates electrical energy in its operation. This further reduces its net electrical load.

---

Please jimh, free energy? You know better than this don't you? Energy is not created or destroyed, it must come from somewhere. The only source of power involved here is gasoline correct? How the heat energy from gasoline is directed to pressurize fuel and inject it into the engine could be a long a complicated process, but it is coming from the gasoline. Let's not turn this into a debate about magic.

posted 02-26-2014 03:18 PM ET (US)         

quote:

---

he notion that the Verado "has been singled out" is perhaps appropriate: it is the only engine with a supercharger, so it seem like it is the only one who can have the load of a supercharger. To ignore the load of the supercharger in the discussion of power output would be more an error than to comment on it.

---

Why should the load of the supercharger be considered? Does the Verado produce less power than the compared outboards? Does the Verado consume more fuel to deliver that power?

If so it might be worth investigating why the Verado cannot perform as well as the compared outboards and the supercharger could a culprit.

Most reports have the Verado performing favorably, being able to generate the highest power (350hp) with good fuel economy even with the supercharger losses.

posted 02-27-2014 09:41 AM ET (US)            

I already explained that anyone could add any engine data they liked to the comparison. And I have responded to every request to add data to my collection, for any engine that has a manufacturer's stated horsepower. I have even taken the trouble and effort to go find the data, scrape it off the websites, and edit the original document to add the data. This is hardly the action that indicates I want to suppress information.

posted 02-27-2014 10:13 AM ET (US)            

If we look at a Mercury FOURSTROKE 75-HP engine, we see it is only being asked to produce 44-HP per liter. Comparing this to the general average of these outboard engines, this engine is producing power at a rate per liter that is rather low. It is, in fact, the lowest power output-per-liter of any engine in the survey. It is even lower than the power produced per liter by the 1960's four-stroke-powr-cycle engine, the Homelite or Boston Whaler BEARCAT, which was able to crank out 51.4-HP per liter.

If we look at the Mercury Verado 200-HP, we see it is being asked to produce 117.6-HP per liter, if we ignore the power it has to make to run its supercharger. If we include the power it has to make to run its supercharger, which is estimated to be 22.2-HP more, then the Verado 200-HP is being asked to make 130.6-HP per liter. It is, in fact, the highest power output-per-liter of any engine in the survey, in either case.

This particular comparison is really interesting because the engine block in this instance is the same block, the four-cylinder in-line 1.7-liter engine block. The power produced from this engine ranges over a very wide span, a ratio of almost 3:1.

posted 02-27-2014 10:14 AM ET (US)            

Now if you wanted to compare and contrast 150hp outboard specs and draw a reasonable conclusion then you would have something.

posted 02-27-2014 10:27 AM ET (US)            

I have added this because it would be dishonest to ignore the significant amount of power produced by a supercharged engine that is used to operate its supercharger. The purpose of the survey is to have a reasonable comparison of the rate at which these engines produce power per liter of displacement, and to ignore the power needed to run the supercharger would significantly understate the power produced in the Verado engines.

It should be clear that this is an estimated power, but it is based on the propeller shaft horsepower and the nature of supercharged engines. Feel free to ignore the data if you think the method insufficiently rigorous in its calculation.

As I mentioned in earlier comments, there are other parasitic loses in all the engines which are not considered, but these losses are common to all of the engines. They all have to turn alternators, and they all have to transmit their power through gears to the propeller shaft. These loads and the power they consume are not considered for any engine. The power taken from the engine to run its alternator will vary with the load on the alternator. If the alternator is not being asked to provide a high current to charge a battery, the load on the alternator is just the load needed to run its own electronics and electrical devices. This is also ignored. All of the engines are using similar electrical devices, consisting of microprocessor controllers and electrically operated fuel injectors. I do not believe there is much variation from engine to engine in this electrical load, and ignoring it in the calculation does not disadvantage or advantage any particular engine.

posted 02-27-2014 10:32 AM ET (US)            

All engines are different depending on the pulley ratio, amount of boost and stage of boost.

Where did you get this information? I have never seen it published and since it is the only supercharged outboard you have no other standard to compare it to?

posted 02-27-2014 10:38 AM ET (US)            

For more about permanent magnet alternators, see an article I wrote about them several years ago:

http://continuouswave.com/whaler/reference/PMA.html

posted 02-27-2014 10:45 AM ET (US)            

quote:

---

Your numbers are fine...

---

Thank you, but the numbers are not my numbers, they are the numbers of the engines, that is, their horsepower and their displacement. I have nothing to do with that.

quote:

---

...the way that you are comparing them is the issue.

---

I compare the numbers by simple arithmetic. Do you have a complaint about the arithmetic? If you have found an error in the calculations, please let me know.

As for the way I am comparing them, I don't understand how there can be a problem--certainly no issue. I compare them any way I want to. This is the beauty of the survey. It collects the data, and it allows the reader to make any comparison he likes.

As we have seen so far, the survey even permits people to look into the mind of other people and accuse them of intentionally making misleading omissions. If one allows that sort of inference to be drawn from the data, then one must certainly allow me to mention a few of the calculations in the data itself.

posted 02-27-2014 10:48 AM ET (US)            

quote:

---

How do you know how much power the Verado supercharger uses?

---

posted 02-27-2014 10:59 AM ET (US)            

For example, you are averaging/comparing the displacement/HP of Mercury Outboards 75hp to 150hp vs Suzuki 90hp to 300hp.

That would be the same as comparing Yamaha 2.5hp to 70hp to Evinrude 115hp to 300hp for displacement.

It does not make sense and the outcome is skewed hence my recommendation to say within a certain HP range.

Also you only state that you are estimating supercharger power draw, where do you get this information? All engines are different depending on the pulley ratio, amount of boost and stage of boost.

Where did you get this information? I have never seen it published and since it is the only supercharged outboard you have no other standard to compare it to?

I hope you are not taking automotive engine information from the internet and applying it this engine because that would mean nothing.

If possible, I respectfully request that you restate where you got this information from as I can not find it in your previous posts.

posted 02-27-2014 11:46 AM ET (US)            

quote:

---

Tom--you should get used to it because I am not changing.

---

posted 02-27-2014 11:56 AM ET (US)            

quote:

---

The reason that I say the comparison is flawed is because you are averaging different HP ranges (of your choosing) without regard to models.

---

Please feel free to re-group the engines in the survey into any arrangement you like. The groupings used in my presentation seemed to me to be very logical. I just grouped the engines according to the manufacturers' usual grouping of them. After the initial grouping, I did not re-arrange the engines into new groups to see if I could alter the data. I have no idea if such a re-arrangement could produce any sort of significant difference in the data.

If you find the comparison of an individual engine's power-per-liter to the average of its group to be flawed, you should just ignore it.

I did not include engines of less than 70 to 75-HP. Feel free to expand the range of engines in the survey. You may uncover amazing new data. The reason I did not include engines of less than 70 to 75-HP is because they are not of much interest to me, and I believe they are not of much interest to most readers who have Boston Whaler boats larger than 13-feet. If engines of less than 70-HP are of great interest to someone, please, whoever you are, go ahead, add them to your survey. I did not have them in my survey.

I did not add multiple models of the same engine power and displacement. For example, in some manufacturers there were instances of an engine with a certain displacement and a certain power but marketed under different model designators. I just used one example. This prevented these multiple model designations from skewing the average for the group.

posted 02-27-2014 12:10 PM ET (US)            

quote:

---

I am also curious to see how you calculate the parasitic supercharger draw difference between a 225hp Verado and a 300 Verado since the powerheads and supercharger are identical with just different PCMs. At 6000 rpm the superchargers are spinning at the same rpm and same power draw because the difference is in the waste gate cal.

The power draw from the supercharger is the exact same on the 225hp as it is on the 300hp so how did you factor that?

---

I don't want to embarrass you, but you are completely wrong. The load on a supercharger that pushes air into a restricted container volume, such as a cylinder, is not the same as the load on a supercharger that pushes air into an open vent to the atmosphere. Air pushed into the cylinder is compressed and that takes work to compress the air. Air pushed out the open gate into the atmosphere is not compressed, and the work being done is less.

I don't mind suggestions that want to add technical rigor to my calculations, but I am afraid I cannot accept suggestions that are completely contrary to the laws of nature.

posted 02-27-2014 12:18 PM ET (US)            

Jimh please tell me the boost numbers any of the Verado engines? How many pounds of boosts is the difference between the engines? How did you determine the power loss of the supercharge since this engine is not like any other engine and no information is published on it?

posted 02-27-2014 12:26 PM ET (US)         

quote:

---

The survey tries to find the horsepower per displacement. In the Verado, the engine is really making quite a bit more power per liter because it has to make the power to run the supercharger.

---

All engines have parasitic losses and therefore produce more power than comes out of the crank. You seem to be singling out Mercury yet again without acknowledging any mitigating factors.

Take the 1.7L Verado 200 and compare to the 3.6L Suzuki 200. Which engine has more net parasitic loss? The naive opinion might be to simply proclaim the Verado has more losses because it has a supercharger, but the larger displacement and two extra cylinders of the Suzuki increases parasitic losses on the crank bearings and ring cylinder interface as well as the oiling system.

How could one possibly figure out which engine has more parasitic loss given the number of variables? It would be extremely difficult to zero in on just parasitic loss, but overall efficiency is easily determined. That is how much gas is required to create a certain amount of power? This is actually what's important, how much fuel to you put in and how much power comes out.

If the Suzuki 200 uses less fuel to create the same power, or the same fuel to create more power, than it is more efficient than the Verado. If this where the case and it where consistently the case across all Verado's compared to various NA designs then a likely suspect would be the supercharger losses. If the Verado has equal efficiency, then the losses from the supercharger were made up by the gains in other areas and the net losses at the crank are the same between designs.

One can see focusing on the losses of a single engine component is myopic and can be counter productive if other data does not point to a discrepancy. This might even be used to confirm a bias if one weren't careful. It would be like complaining about money put into a profitable investment as though it was spent when in reality money is made not lost. The engine is investing horsepower in a supercharger to get a higher return.

posted 02-27-2014 02:16 PM ET (US)         

As the piston goes down on the intake stroke the compressed intake charge pushes on the piston adding power back into the crank. Not all loss is recovered as some is converted into heat in the compression process, but a significant amount is.

posted 02-27-2014 03:04 PM ET (US)            

Total Power of Engine - Power to Run Supercharger = Net Power Out.

OMCrobert has tried to argue that the power to run a supercharger is a fixed amount and never varies with the amount of boost the supercharger provides. I think I have demonstrated that argument to wrong. But let me know if anyone still believes in it. I will try to dissuade you.

It is not absolutely necessary to find a method for determining the other power losses in an outboard engine for the purpose of the survey, as all the engines have these losses. As I explained already, I don't have a good method for determining them, and particularly to determine how the operation of one engine might differ from the other. I don't know how to account for the loss incurred in spinning balance shafts compared to not having them.

I also did not add on any extra horsepower in the OptiMax to account for its air compressor. As I said earlier, I don't think the air compressor load is more than a few horsepower. Trying to figure out a difference of 2-HP in a 200-HP engine sounds like splitting hairs. Trying to allow for a difference of 22.2-HP in a 200-HP engine is a reasonable method.

posted 02-27-2014 04:30 PM ET (US)         

quote:

---

I don't have a good method for determining them, and particularly to determine how the operation of one engine might differ from the other.

---

There is no good method for determining a supercharger loss as I have shown. Some power is robbed from the crank to compress air it is then pushed into the cylinder and some of that power is immediately returned to the crank, this is before we even get into the next combustion cycle that utilizes the compressed charge. Only focusing on one side is not helpful unless one were trying to unfairly criticize an engine.

quote:

---

Trying to allow for a difference of 22.2-HP in a 200-HP engine is a reasonable method.

---

But as I have shown it is not a 22.2 hp difference. It is less, how much less?

quote:

---

I also did not add on any extra horsepower in the OptiMax to account for its air compressor. As I said earlier, I don't think the air compressor load is more than a few horsepower.

---

You certainly didn't want add on any horsepower for an E-TEC alternator, it wasn't even mentioned until I brought it up, yet the Mercury Optimax compressor is required for "strict comparisons".

posted 02-27-2014 04:39 PM ET (US)            

If all the engines had superchargers, it would be reasonable to complain that I only considered the supercharger load on one engine. But since only one engine has a supercharger, it is not reasonable to ignore it. But, since I made two separate listings, you can simply ignore the supercharger load, it you want to ignore it and pretend it does not exist.

Your comment about the OptiMax is completely backwards. I have ignored the load of the air compressor. I said it was there but was probably not very large and could be reasonable ignored.

As I understand it you think I should:

--ignore the load of the supercharger on the Verado, even though it is the only engine to have one;

--include the load of the alternator only on the E-TEC, even though all engines have alternators;

--include the load of the OptiMax air compressor, even though I said it was probably on a few horsepower and could be ignored.

posted 02-27-2014 05:02 PM ET (US)         

quote:

---

You must be kidding. All the engines have alternators. Why would I only account for the alternator load on one engine and not the other? That would be outrageously biased!

---

Not all engines have voice coil high pressure injectors running at 700psi running off a 55 volt permanent magnet alternator.

Not all engines have this, yet only Mercury's unique design was targeted.

quote:

---

If all the engines had superchargers, it would be reasonable to complain that I only considered the supercharger load on one engine. But since only one engine has a supercharger, it is not reasonable to ignore it.

---

Only one engine has electric high pressure injectors.

quote:

---

Your comment about the OptiMax is completely backwards. I have ignored the load of the air compressor. I said it was there but was probably not very large and could be reasonable ignored.

---

Only after I had to point out that the E-TEC injection system was omitted and disapprove your math where you attempted show the electrical system on the E-TEC was not comparable to an Optimax air compressor, even though it clearly is.

quote:

---

ignore the load of the supercharger on the Verado, even though it is the only engine to have one;

---

Yes unless you can accurately provide what losses it truly has and contrast it with the losses a larger displacement engine with more cylinders has in the same horsepower range, otherwise the information is one sided and provides little value.

quote:

---

include the load of the alternator only on the E-TEC, even though all engines have alternators;

---

Only if the Optimax Injection compressor is included, which you attempted to do initially.

quote:

---

include the load of the OptiMax air compressor, even though I said it was probably on a few horsepower and could be ignored.

---

posted 02-27-2014 05:13 PM ET (US)            

If one can dismiss any statement as invalid because it was made on-line, then one can certainly dismiss that notion itself. This line of argument becomes a black hole that devours itself.

Regarding the power consumed by a supercharger when it is operating at maximum engine power, I have repeated requested that critics of my method offer an alternative method. For these critics to offer only the criticism that the my method in wrong because they think I read it on-line is ridiculous on two accounts:

--I have never made any statement about where my method originated; the critics have no idea who originated my method, if not me, nor where I found it recommended, if not self-invented; and

--the logic of their justification--it's on-line--cancels their own criticism.

posted 02-27-2014 05:29 PM ET (US)            

The dispute arises because jharrel began a flawed line of argument that the electrical power of operating an E-TEC fuel injector was such a significant load that it would be necessary to consider it in the same way the supercharger load of the Verado has to be considered. I simply pointed out the the E-TEC fuel injector has patented designs which allow it to uses its mechanical motion, which otherwise would be lost energy, to create electrical energy for its own operation. It is really a very crafty design, and apparently not employed in prior art because it is patented. It takes advantage of the reciprocating motion of the injector.

Now the supercharger on a Verado is also a crafty design. Its blades are machined to very close tolerances to get the most efficiency. I believe there is Teflon coating to protect the metal from the effect of salt air. It is a beautiful--and expensive--machine to compress air and force air into the cylinders of the engine to boost their power production. And in the very same way as the E-TEC injector, it generates some of the power that runs it. You see, in order to get the power to run the supercharger, the supercharger has to force more fuel into the engine so it can create more power. If the supercharger could not create more power than it took to run the supercharger, there would be little reason to add a supercharger.

posted 02-27-2014 06:01 PM ET (US)         

quote:

---

jharrel suggests that I have invoked the term free energy/ This is false. I never used it.

---

quote:

---

Finally, the voice-coil injector of the E-TEC uses a sort of dynamic braking technique in which the movement of the injector piece in the magnetic field of the coil actually generates electrical energy

---

Since you weren't implying free energy, where does the energy come from that the injectors generate?.

quote:

---

The dispute arises because jharrel began a flawed line of argument that the electrical power of operating an E-TEC fuel injector was such a significant load that it would be necessary to consider it in the same way the supercharger load of the Verado has to be considered.

---

STOP RIGHT THERE. You not me tried to consider direct injection in the same way to supercharger load:

quote:

---

If a more strict comparison were to be made, it would have to consider the parasitic losses in the Verado supercharger and OptiMax air compressor which are not present in the other engines when looking at the power generated by the engine per liter of displacement.

---

Then again you tried to compare it to a supercharger load:

quote:

---

The alternator on these engines generates the electrical power. In order to have 22.2-HP of loss (the estimate for the supercharger) we would need

---

Stop trying to misdirect and compare injectors to superchargers and blame me for it.

If you didn't want to discuss losses for two-stroke direct injectors, then you should not have brought it into the conversation. If you do wish to talk about one engines fuel injector system load I only think its balanced to bring up the others.

posted 02-27-2014 06:38 PM ET (US)         

quote:

---

I am afraid if anyone is making an argument for free energy, it is jharrel. He wants to ignore the energy the supercharger takes from the engine to turn the supercharger. My suggestion to not ignore this is a suggestion against free energy, and I this most readers will recognize this.

---

You want to cherry pick, not ignoring supercharger losses, but ignoring friction and pumping losses from a larger displacement engine.

Let me make it clear lest anyone get the wrong idea. I do not believe superchargers generate energy. They are part of a system that helps convert heat energy into kinetic energy.

Focusing on a superchargers power draw at it's pulley is no different than focusing on increased piston ring friction from a larger diameter piston. It is interesting information that needs to be taken with much other information to draw any conclusions, if only one part of the information is available, no meaningful conclusion can be made.

For some reason jimh thought the Verado's supercharger and the Optimax's air compressor needed mentioning, yet thought the Yamaha Offsore's large displacement, or E-TEC's alternator did not need mentioning. One can only guess his motives.

posted 02-28-2014 09:12 AM ET (US)            

Now here comes jharrel and he says that moving the pistons up and down is a load, too, and that needs to be considered. jharrel says there are subtleties about the volume of the cylinder that make the load vary--or at least that is what I think he said--so that this affects engines of different displacement in different ways.

Then jharrel says that by considering something very obvious as a load like a supercharger, but not considering something very subtle like the difference in some characteristic he calls "pumping loss" due to cylinder volume is ab inconsistent method. And even further, he imparts the notion that failing to consider the very subtle while considering the very obvious is evidence of a sinister motive, although he never really comes out and explains what the motive is.

This is nonsense. Failing to consider the very subtle but acknowledging the very obvious is not a result of a sinister motive. It is a result of not understanding the very subtle.

I will now sit back and let jharrel explain how some very subtle thing about the difference in a larger volume displacement engine compared to a small volume displacement engine is going to affect in a significant way the manner in which power is produced as a function of displacement. And please make the explanation be:

--so simple we can understand it, and

--so compelling that we see how not considering this renders all of the data in my survey to contain some inherent bais that renders it totally unreliable

posted 02-28-2014 01:47 PM ET (US)            

quote:

---

where does the energy come from that the injectors generate?

---

The electrical energy generated by the E-TEC fuel injectors is harvested by using the reciprocal motion of the injector in the voice coil. The design is brilliant.

It is well known that arrangements of electrical motors can become electrical generators if the input and output energies are reversed. An electrical motor that has an input of electrical energy and an output of mechanical energy can be reversed, and it will be come a generator if mechanical energy is input; electrical energy will be generated.

This same method is used in the E-TEC injector. The application is brilliant because the linear motor of the injector is reversed to become a generator, and the electrical power output stored for use on a following cycle of the injector. At the same time, the reversal or dynamic braking technique is used to decelerate the injector moving part to a soft landing, reducing the annoying acoustic clatter of the usual injector. This makes the invention brilliant. Not only does it solve a problem of acoustic clatter noise reduction, but it harvests the electrical energy for use on the next cycle. This invention is a new method and was rewarded with a patent as a useful invention.

For more about electric motors and generators and dynamic braking, see

http://en.wikipedia.org/wiki/Dynamic_braking

In most applications of dynamic braking the electrical energy generated is just absorbed in resistors, which create waste head, which has to be carried away by fans. The brilliant part of the E-TEC fuel injector is that the electrical energy generated is stored and use to run the injector itself.

We got onto this discussion because of a distracting claim made (by jharrel, as I recall) that the electrical energy needed to run the injectors in an E-TEC had not been considered as a parasitic load on the engine, while the supercharger of the Verado had been. As I pointed out, all the engines used fuel-injectors, so the use in the E-TEC was by no means unique, whereas the use of the supercharger in the Verado was unique. I also pointed out that the OptiMax has two injectors per cylinder, so that if there should be any accounting for extra electrical power consumption, it was probably the OptiMax that was consuming the most power running its injectors. The survey overlooks the electrical load of the injectors for all engines, thereby giving the OptiMax a pass on its doubled injectors and their electrical load. It seems to be that if any engine were to be advantaged by neglect of the electrical load, the one most favored by this would be the OptiMax and the one least favored by this would be the E-TEC (since its injectors operate as generators for part of their cycle).

posted 02-28-2014 02:45 PM ET (US)         

quote:

---

I think it is well known that I do not design internal combustion engines as my profession, so it should also be recognized that I cannot know all the subtleties associated with designing internal combustion engines.

---

I am sorry that two more cylinders, with more crank bearings, and larger heavier cylinders, and more oil are a subtle distinction in your mind.

I think to most people who have some knowledge of engines realize this is not a subtle difference.

I think if one can't recognize such distinction and may not have a firm grasp on them they might refrain from trying to point out that a certain engine has more parasitic loss than another lest they look bias when infact it is simply ignorance.

posted 02-28-2014 04:28 PM ET (US)            

The comparison I made is of two engine that are identical, except for the supercharger. I mentioned the three-to-one ratio in power output between the 75-HP version and the 200/222-HP version. So what extra losses were overlooked there? The engine displacement, configuration, and number of cylinders are the same in both. Why can't they be compared? Please explain how that is not a reasonable comparison.

posted 02-28-2014 05:04 PM ET (US)            

quote:

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Tom--you should get used to it because I am not changing.

---

Then Tom replies:

quote:

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I fully recognize that fact, Jim. You're a bright fellow. Surely you recognize that I am not either. Get used to it.

---

posted 02-28-2014 05:36 PM ET (US)         

quote:

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MIt was once reported that the air compressor of the OptiMax was actually made by using a block, piston, and other components from a 3-HP outboard engine made by Mercury sometime earlier.

---

The displacement of an air compressor being equal to an internal combustion engine would be very bad way to determine the the power needed to drive it. This is an area where again you may be out of your depth and should refrain from speculation. Internal combustion engines generate pressures in the thousands of psi, the Optimax air compressor generates 90 psi.

The power needed for an air compressor is based on pressure and volume can be found here:

http://www.engineeringtoolbox.com/horsepower-compressed-air-d_1363.html

Optimax injectors need only 1.1cc of air at 90psi per injection. This works out to 1.398 CFM at 6000 rpm for a V6 Optimax.

This would require .21 HP to produce in a single stage air compressor.

quote:

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It is well known that arrangements of electrical motors can become electrical generators if the input and output energies are reversed. An electrical motor that has an input of electrical energy and an output of mechanical energy can be reversed, and it will be come a generator if mechanical energy is input; electrical energy will be generated.

---

In other words it recovers some of the energy already used, I hope you are not implying it recovers 100% of the energy and the E-TEC injectors are run for free.

You know what also recovers some of it's energy, a supercharger, and a Optimax air compressor, since each forces compressed air into the cylinder pushing against the piston on a intake stroke. Amazing that you did such extensive research on the E-TEC injector design and fully explained the regenerative system it detail using such adjectives as "brillant" and completely missed the same obvious fact about the Mercury designs.

quote:

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We got onto this discussion because of a distracting claim made (by jharrel, as I recall) that the electrical energy needed to run the injectors in an E-TEC had not been considered as a parasitic load on the engine, while the supercharger of the Verado had been.

---

No jimh, there you go again. I would have never mentioned the E-TEC injectors if you did not mention the Optimax injectors. You conflated superchargers and injectors, not me. Own up to it, stop trying to blame me for it.

quote:

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I also pointed out that the OptiMax has two injectors per cylinder, so that if there should be any accounting for extra electrical power consumption, it was probably the OptiMax that was consuming the most power running its injectors.

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I pointed your flawed logic here. I guess I must repeat it again. Optimax's have two-injectors, one is a standard automotive fuel injector. I believe these injectors draw about 3 watts. This is because the fuel pressure come from a medium pressure electric fuel pump running about 25psi, the injectors simply open and close, they create no pressure. Guess what engine also has a 25psi electric fuel pump, the E-TEC. This means the Optimax and E-TEC have nearly identical power requirements through the first stage. The second injector used in an Optimax is high-pressure and driven by the air compressor, it runs at 90psi. The E-TEC injectors run at 700psi, which is generated in the injector itself from electricity. It doesn't take a genius to realize the E-TEC injectors have higher electrical requirements than the Optimax's, much higher.

quote:

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It seems to be that if any engine were to be advantaged by neglect of the electrical load, the one most favored by this would be the OptiMax and the one least favored by this would be the E-TEC (since its injectors operate as generators for part of their cycle).

---

So your are really attempting to say the Optimax injectors require more electricity than the E-TEC, because 2 is greater than 1. Come on jimh, I know you have electrical knowledge, I also know you attempted to calculate the E-TEC injectors electrical draw in great detail on this forum and it was much higher than 3 watts even at idle speeds, what was it at 6000 rpm again? I believe it was 110 watts! So a V6 E-TEC requires 660 watts at 6000rpm, or .89hp while the Optimax uses only .21hp less than a third of the power. Yet for some reason the Optimax's pump needed mentioning but the E-TEC's alternator did not?

quote:

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When I compare the Verado 1.7-liter to the FOURSTROKE 1.7-liter I am comparing the same engine block, same number of cylinders, same displacement, and so on.

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Why would you compare parasitic losses of a 75hp engine to a 200? Every 200hp engine from every manufacturer has more parasitic losses than their 75hp version. The Verado uses a supercharger, other manufacturers use larger displacement and more cylinders. Both result in more losses, the only one you attempted to single out was the Verado and the Optimax.

quote:

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I am waiting to hear more about the wonderful subtleties I have failed to take into account when I took displacement and divided it by horsepower.

---

posted 02-28-2014 06:06 PM ET (US)            

You initially tried to suggest the electrical load of an E-TEC's injectors load was on par with the supercharger, I pointed out that would mean a load of about 16,000-watts. On a six-cylinder engine that would mean 2,666-watts per injector. I don't think the E-TEC injectors consume anywhere near that sort of power. I don't have any data on the actual power consumed, but judging by the wiring running to them, they are not each consuming kilowatts of power.

I don't recall calculating their electrical consumption. If I did, please tell me where. I would like to read what I wrote.

The term free energy was not used by me. I cannot take responsibility for introducing it into the discussion. You introduced it to try to ridicule the very sound basis on which the E-TEC injectors regenerate some of the electrical energy they need to run by harvesting the mechanical energy. See my explanation above. It does not suggest free energy.

The supercharger does not really generate the power that runs it. The fuel burned in the engine generates the power. The supercharger allows more fuel to be burned, so more power can be generated.

In order for the supercharger to be analogous to the electrical energy harvested in the E-TEC injector, there would have to be some sort of use of the rotational energy in the supercharger when it wasn't using that energy to force air into the engine. I suppose you could say the rotational energy in the supercharger is like a flywheel, and when the throttle is cut it tries to keep the engine spinning. But I don't think that is quite as effective as the E-TEC's electrical regeneration. This is a sidebar dispute.

Your main claim is that even mentioning the supercharger on the Verado was some sort of display of horrendous bias. That claim in wrong, because the supercharger certainly does impose a load on the Verado that is not present on any of the other engines.

Now, having just said that, I suppose I could mention that all of the two-stroke-power-cycle engines are themselves a lot like a supercharged engine because they use their own piston stroke to pump air into the combustion chamber. But this is another technical sidebar. I don't think it is worth following.

The main argument between you and me is about my mention of the Verado having to create its own power to run its supercharger. There is no denial of that. Whether or not the mention of this constitute an outrageous example of bias is mostly in the mind of the reader. It has no bias in my mind. As I said, to ignore the supercharger would be more bias than to mention it. To ignore all the little possibilities for differences among the many engines in the survey due to all the sublteties you have suggested, is, in my mind, not a huge error. The survey did not include the Verado, but when you and other insisted it must be included, I found appropriate to mention the higher load the supercharger creates. I included in the survey separate tables, and if you don't like my estimates for the Verado power considering the supercharger load, you can just ignore them.

posted 03-01-2014 11:21 AM ET (US)         

quote:

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You initially tried to suggest the electrical load of an E-TEC's injectors load was on par with the supercharger, I pointed out that would mean a load of about 16,000-watts.

---

There you go yet again. Where did I suggested this? You keep repeating this as though if you do it enough it will become true, are you trying to convince yourself?

quote:

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If a more strict comparison were to be made, it would have to consider the parasitic losses in the Verado supercharger and OptiMax air compressor which are not present in the other engines when looking at the power generated by the engine per liter of displacement.

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Your words not mine. I have shown the E-TEC injectors have more parasitic losses than the Optimax Injectors.

quote:

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I don't recall calculating their electrical consumption. If I did, please tell me where. I would like to read what I wrote.

---

http://continuouswave.com/ubb/Forum4/HTML/007838.html

quote:

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In order for the supercharger to be analogous to the electrical energy harvested in the E-TEC injector, there would have to be some sort of use of the rotational energy in the supercharger when it wasn't using that energy to force air into the engine. I suppose you could say the rotational energy in the supercharger is like a flywheel, and when the throttle is cut it tries to keep the engine spinning. But I don't think that is quite as effective as the E-TEC's electrical regeneration. This is a sidebar dispute.

---

Besides the obvious fact that the compressed air created by the supercharger is forced into the engine pushing the cylinders down returning energy to the crank? Sure the flywheel analogy is often used for electrical coils, why would you assume the E-TEC injector is more efficient at conserving energy than a supercharger or OptiMax air compressor, do you have data, or you simply like E-TEC's better?

quote:

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Your main claim is that even mentioning the supercharger on the Verado was some sort of display of horrendous bias. That claim in wrong, because the supercharger certainly does impose a load on the Verado that is not present on any of the other engines.

---

Larger displacement engines and those with more cylinders have a similar increased parasitic load that you did not account for. That is why the Verado can make just as much power while still having equivalent fuel economy, because it parasitic losses are equivalent. If they where higher then power would be lower or fuel economy would be worse.

quote:

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Now, having just said that, I suppose I could mention that all of the two-stroke-power-cycle engines are themselves a lot like a supercharged engine because they use their own piston stroke to pump air into the combustion chamber. But this is another technical sidebar. I don't think it is worth following.

---

In a crank-case scavenged two-strokes like the E-TEC, yes, this is why pumping losses are quite high at high rpm's in this design while made up with the more compact design. More sophisticated two-stroke designs actually use supercharger like blowers to scavenge instead of the crank case so that they may use a wet sump with oil pan and not burn oil. They also have a valve train with exhaust valves, this is referred to as uniflow-scavenging and considered the most efficient two-stroke design.

quote:

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The survey did not include the Verado, but when you and other insisted it must be included, I found appropriate to mention the higher load the supercharger creates.

---

Except you neglected the higher load a larger displacement engine creates one with larger pistons, more cylinders, larger valves, more valves, more oil, more bearings, larger bearings. You may not have a clear grasp on these "subtleties" but I have shown you don't even have a clear grasp on the amount of a power a supercharger uses, neglecting the energy it returns to the crank on the intake stroke. Even without this clear grasp you thought it must be mentioned, why? If the Verado where making less power or consuming more fuel than other equivalent engines it might be worth analyzing, just like it might be worth analyzing the higher load the two extra cylinders of a V6 have versus a I4.

quote:

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Anything else you don't like in the data?

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I don't like you twisting my words regarding supercharger vs E-TEC alternator, stop it and admit you brought the OptiMax injector system into the discussion and made an error suggesting it requires more power than the E-TEC injector system.

quote:

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I would be glad to consider other complaints, but I am getting tired of the personal attacks about trying to present some secret agenda.

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I am trying to help here jimh by bringing balance to the discussion, I would call this constructive criticism. A reasonable person might see the number of complaints of their bias and see how they can improve the content of the information provided rather than taking personal offense and ignoring the complaints.

posted 03-02-2014 01:56 PM ET (US)            

Electrical power consumption of fuel injectors

Thanks for the pointer to my article about the E-TEC voice coil fuel injector. If you can tell me the DC resistance of the OptiMax fuel injectors I could estimate their power consumption using the same method, and we could have data that could be compared. I believe you came up with your own estimate for the electrical power of the OptiMax injector, but your method was entirely different from mine. I think if one is going to compare estimates, the same method should be used for both data being compared. Just let me know the DC resistance of the 12 injector solenoid coils for the OptiMax, and I can proceed with my estimate of their electrical power using the method I used for the six E-TEC voice coil injectors. I have to say, my method is a bit crude because it does not take into account any sort of back-EMF that might occur from the field of the coil. It is not a particularly rigorous method. But if it is to be used to calculate the E-TEC injector, it can be used to calculate the OptiMax. However, there is one distinct difference: the voltage applied to the E-TEC injector is modulated or varied, but I believe the voltage applied to the OptiMax injector is not. That voltage is either on or off, nothing in between. The E-TEC injector voltage varies in amplitude and polarity, and might be harder to use to calculate the power. But we can see how the comparison results.

Correlation of power to run supercharger to power to run electrical injectors

Again, the very different manner in regarding the electrical load of the fuel injectors compared to the mechanical load of teh supercharger is quite simple: all the engines have fuel injectors, so we are now quibbling about the relative amount of electrical energy they consume. Only the Verado has a supercharger, so we cannot possible pretend that all of the other engines have lost power running their supercharger--they don't have one.

I am certain I did not invent myself the notion that there was an attempt being made to connect or corollate the power driving the supercharger to the electrical power driving the E-TEC injectors. If you are declaring now that you are making no such linkage and it is not comparable, I will be glad to stop trying to argue that the linkage is not comparable. If you say the two are not equivalent, I am very glad to accept that. That should end this part of the argument.

I am sure you will not agree to that stipulation, and you are going to continue to try to justify yourself in objecting to the accounting of the lost power to drive the supercharger by insisting the E-TEC losses power running its injectors. So I will have to persist in my objection, which I restate, again:

--the power lost running the supercharger is much greater than the power needed to run the injectors, so I find that the two are not comparable, other than they both represent loads on the engine;

--all the engines have electrical injectors, but only the Verado has a supercharger;

--the electrical load of the OptiMax injectors is likely of the same magnitude as the electrical load of the E-TEC injectors

--refer to the calculation of over 16,000-Watts of electrical power being needed to make the E-TEC load comparable to the supercharger. This can be seen to be incongruent by just looking at the wiring of the injectors; it could never carry 16,000-Watts of electrical energy.

Regarding the potential to achieve improvements in efficiencies with small displacement engines using superchargers

If one looks at automobile engine technology one sees a clear trend away from very large displacement engines toward smaller displacement engines with some sort of boosted induction pressure, usually turbo-charger boost not supercharger boost. It might be possible to infer there was some general principle in play with engine design that was causing engines to become smaller displacement because they held some elements of design that allows them to become more efficient .I would characterize there is a very strong incentive for automobile engines to look for every possible way to improve fuel efficiency. Therefore, if looking at automobile engines as a guide, I would tend to infer that there must be some advantage to smaller displacement compared to larger displacement in achieving good efficiency. Since good efficiency implies less parasitic losses, I can make a general inference that smaller displacement may have less parasitic losses than larger displacement. I believe this is the general trend you wish to put forward and are using as a criticism of my survey and its special handling of the load of the supercharger of the Verado.

Since I don't have any method to know the comparative losses of high displacement engines compared to low displacement engines, and from the failure of jharrell to give us some sort of formula or algorithm to compute them on a scientific basis, I am completely willingg to admit I just ignore them. If this is a problem in the survey which taints the data, it taints all the data. I cannot account for something which I cannot measure. Remember the survey just takes the displacement and horsepower of all the engines as given by the manufacturers. The only data not from the manufacturer is the estimation of the load of the supercharger, a unique element found only in the Verado.

The roots of all evil
We again back to the fundamental problem for jharrell in my comments: I dared to mention that the supercharger on the Verado needs to consume power to run, this power came from the engine, and that one might consider that this power could be estimated and figured as part of the total power being generated.

If I may, I will characterize jharrell's objections to this to be mainly along a line of argument that goes like this:

--there are other loads on an engine which reduce its net power output

--it is not fair to consider only the supercharger and to ignore the other loads

My response to this is simple:

--the supercharger is a unique element of the Verado and does not appear on the other engines in the survey;

--there is no reasonable method to assign measurements of loss for every engine based on all the details of its design to account for every possible parasitic loss. For example, some engines have multiple cam shafts and multiple balance shafts that must be rotated. Some engines, the E-TEC for example, have no cam shafts and no balance shafts. Thus by not considering the loads of things like a cam shaft or a balance shaft, the survey tends to penalize the E-TEC and reward all the four-stroke-power-cycle engines. This is actually quite a funny outcome because it has been alleged by some mind readers that the purpose of the survey was to produce an outcome that would put the E-TEC "on top" (in the words of my critics).

posted 03-03-2014 01:13 PM ET (US)         

quote:

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If you can tell me the DC resistance of the OptiMax fuel injectors I could estimate their power consumption using the same method, and we could have data that could be compared.

---

air injector 1.3 ohm
13.4v / 1.3 = 10.30 amps
13.4v * 10.30a = 138 watts peak
138w * .1 duty cycle = 13.8w

fuel injector 12 ohm
13.4v / 12 = 1.12 amps
13.4v * 1.12a = 15 watts peak
15w * .1 duty cycle = 1.5w

Total = 15.3w

About 1/7th the amount of an E-TEC injector.

I do think however your calculation for the E-TEC injector is low, probably the duty cycle is too low. The reason I say this is because the alternator capacity dedicated to the engine. A V6 E-TEC has a 1800 watt (133 amp) alternator with 50 amps of available capacity for charging. This means 1200 watts (1.6hp) are dedicated to the engine systems, far higher than any other outboard. As a comparison the Optimax only has a 756 watt alternator, less than half the output. Why would Evinrude dedicate 1200W to the engine if unused?

Your words:

quote:

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The portion of the permanent magnet alternator output current which is not available for battery charging is used to operate the engine itself.

---

quote:

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Therefore, to produce 1,800-watts of electrical energy from the mechanical energy of the motor will consume only about 1800/750 = 2.4-HP (or probably slightly more as the conversion will not be perfectly efficient).

---

http://continuouswave.com/ubb/Forum6/HTML/001168.html

I know of no other outboard that produces or requires 1800 watts of power, this is in fact more than double any other outboard in production including the Optimax.

quote:

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all the engines have fuel injectors, so we are now quibbling about the relative amount of electrical energy they consume.

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All engines don't have 1800 watt alternators or E-TEC injectors, very unique design, you have extolled upon this unique design over and over, no one else does it.

quote:

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I am certain I did not invent myself the notion that there was an attempt being made to connect or corollate the power driving the supercharger to the electrical power driving the E-TEC injectors.

---

quote:

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If a more strict comparison were to be made, it would have to consider the parasitic losses in the Verado supercharger and OptiMax air compressor which are not present in the other engines when looking at the power generated by the engine per liter of displacement.

---

quote:

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the alternator on these engines generates the electrical power. In order to have 22.2-HP of loss (the estimate for the supercharger) we would need

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I am not sure what to make of this ridiculous repetition and denial. One only need read the previous posts to see you where the first and only one to connect and correlate DI losses with supercharging, no one else has.

quote:

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all the engines have electrical injectors, but only the Verado has a supercharger;

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This is like saying all engines have air induction only E-TEC's have high power voice coil injectors. True and meaningless.

quote:

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there is no reasonable method to assign measurements of loss for every engine based on all the details of its design to account for every possible parasitic loss. For example, some engines have multiple cam shafts and multiple balance shafts that must be rotated. Some engines, the E-TEC for example, have no cam shafts and no balance shafts.

---

You right there is no easy way to measure this including the losses for a supercharger or for the crank-case scavenging losses in an E-TEC or for the 2 extra cylinders in an E-TEC 200 vs an Verado I4. To pick out one element of an engine and use it for to form opinions is folly.

quote:

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his leads me to this question: if the load of the OptiMax air compressor is much less than 3-HP, and if the compressor is made from the parts used in a 3-HP engine, why do the OptiMax air compressors fail so often?

---

Fail more often than what? An E-TEC injector? Is there some source of reliable data for which fails more often? I am sure I can find instance of both failing. What does this have to do with parasitic losses? Does something that uses more power fail more often? This is classic petitio principii.

posted 03-08-2014 03:29 PM ET (US)            

He says this is seven times more than the electrical power of the OptiMax injectors. Let's assume this is true. To properly balance these loads we have to add up all the energy used in injecting the fuel

For E-TEC = electrical load of injectors

For OptiMax = electrical load of injector + mechanical load of air compressor

jharrell's estimate of 1.5-HP in the E-TEC for added load is about half my estimate of the added air compressor load in an OptiMax. This seems reasonable. If we are going to have the energy to push fuel into the combustion chamber under pressure in both engines, it would be reasonable that the amount of energy might be the same. The E-TEC uses electrical energy to raise the pressure of the fuel as it is injecting it. The OptiMax uses an air compressor to raise the pressure and then an injects it electrically.

jharrell wants to make a comparison of injectors to injectors, and reap the reward. I suggest we compare injectors to injectors plus air compressor.

It is necessary in any analysis of energy to consider the energy in all forms.

According to jharrell's theory, an E-TEC requires seven times more electrical energy to run than an OptiMax. This theory conflicts with reality. It is well known that at low engine speeds an OptiMax cannot generate enough electrical energy to run itself. It must have an external source of electrical energy, the battery, to provide the electrical energy it needs to run. The E-TEC is profoundly different. It generates enough electrical energy to run itself without a battery, even a very low idle speeds.

posted 03-08-2014 04:13 PM ET (US)         

quote:

---

jharrell's estimate of 1.5-HP in the E-TEC for added load is about half my estimate of the added air compressor
load in an OptiMax.

---

Your estimate for the Optimax compressor is based on nothing other than it's displacement being similar to a 3HP outboard. This makes no sense to anyone who knows how air compressors work.

Based on the pressure and volume needed by the Optimax injectors the compressor should need less than 1/4 HP as I showed earlier. For it to require 3HP would mean it was only 8% efficient, which is a ridiculous suggestion.

Let say the Optimax compressor is only 50% efficient which is still ridiculous then we are looking at roughly 1/2 HP for the compressor. This plus the electrical load of the injectors of 15 watts or .02 HP is .52 HP or 1/3 the E-TEC parasitic load.

This is no surprise given the Optimax system runs at 90 psi while the E-TEC at 700 psi.

posted 03-08-2014 04:26 PM ET (US)         

quote:

---

It is well known that at low engine speeds an OptiMax cannot generate enough electrical energy to run itself. It must have an external source of electrical energy, the battery, to provide the electrical energy it needs to run.

---

posted 03-09-2014 08:59 AM ET (US)            

--demonstrate the power consumed in the supercharger of a Verado using a 250-HP engine as an example.

posted 03-09-2014 09:21 AM ET (US)            

--among a group of two-stroke-power-cycle engines, the E-TEC and OptiMax, the power produced per liter of displacement is very similar;

E-TEC = 67.6-HP/LITER average
OptiMax =69.4-HP/LITER average

--among a group of four-stroke-power-cycle engines, the Yamaha, Suzuki, Honda, the power produced per liter of displacement is similar:

Yamaha = 62-HP/LITER
Yamaha = 61.5-HP/LITER
Suzuki = 60.7-HP/LITER
Honda = 59.3-HP/LITER
Mercury = 53.7-HP/LITER

None of the above engines use a supercharger.

If consider the power produced per liter of displacement of engines with a supercharger, we see:

--among a group of four-stroke-powr-cycle engine, the Verado, the power produced per liter of displacement is significantly higher than either the two-stroke or four-stroke comparison groups:

--Mercury Verado = 101.3-HP/LITER

This comparison is even more striking when one considers that the Verado engines are otherwise identical to the non-Verado four-stroke-power-cycle engines previously mention.

It is clear that the supercharger is doing some work to increase the power output, and that it is powered from the engine itself. While the supercharger does allow the engine to make more power, in the process the supercharger must consume some power from the engine to run.

There is a dispute about the magnitude of the work done by the supercharger, which has become the main topic of this discussion. We have seen that adding a supercharger results in a very significant increase in power output: the output almost doubles. For example, we see in the 1.7-liter Mercury:

Non-supercharged FourStroke = 115-HP at best
Supercharger Verado = 200-HP at best
Increase = 85-HP or 74-percent.
or consider

Non-supercharged FourStroke = 75-HP at worst
Supercharger Verado = 150-HP at worst
Increase = 75-HP or 100-percent

We are told that a supercharger can create this increase in power output, but not consume any more power than is used by devices in other engines, and yet the Verado itself has many of those devices, such as an alternator.

The notion being suggested by those who insist the supercharger represents nothing out of the ordinary in terms of load on its engine is that the supercharger is some sort of miracle device. A supercharger can literally double the power output of an engine while consuming so little energy that no notice or accounting for it should even be considered.

I disagree. I believe the energy to run the supercharger should be accounted for. I am still waiting for someone to come forward and account for the energy used by the supercharger.

Up to this point, all the arguments just try to deflect attention onto other devices on other engines that might consume energy. None of these arguments has identified any device that consumes more than perhaps 0.5-percent of total power.

This argument fails because all the other engines create power per liter of displacement at a similar rate, and that rate is markedly different from the rate of the Verado.

There has been an attempt to draw an inference that because on some other engines there are devices that consume power from the engine in a very small fraction of total power, we must assume this also applies to the supercharger. But no such basis has been demonstrated.

posted 03-09-2014 09:34 AM ET (US)         

quote:

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The E-TEC is reported to and has been demonstrated to start and run without a battery attached. No such reports or demonstrations exist for the OptiMax.

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I believe many EFI outboards will not operate without a battery attached, this is not unique to the Optimax.

posted 03-09-2014 10:11 AM ET (US)         

quote:

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the notion being suggested by those who insist the supercharger represents nothing out of the ordinary in terms of load on its engine is that the supercharger is some sort of miracle device.

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I hope this is not in reference to something I said. I merely point out that for an 1.7L outboard engine to produce 200HP something must change, either an increase in displacement or a supercharger, both approaches increase parasitic load on the engine. You seem to be ignoring this fact.

I have shown that even a 200HP 2-stroke E-TEC with no supercharger or valve-train has higher loss than your theoretical 1.7L 200HP engine that is being used to calculate Verado supercharger loss.

You want the value for the Verado supercharger loss so bad, yet you seem to have no desire to figure out why the E-TEC has higher loss as well.

quote:

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Up to this point, all the arguments just try to deflect attention onto other devices on other engines that might consume energy. None of these arguments has identified any device that consumes more than perhaps 0.5-percent of total power.

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Need I remind you yet again you brought up Optimax injectors, perhaps you should have left them out of the discussion? I simply pointed out your bias as you never even thought to mention the E-TEC injectors yet they draw more power from the engine compared to the Optimax system.

posted 03-19-2014 02:19 PM ET (US)            

There seems to be more concern about why I am interested in the supercharger than there is in finding the answer to my question. While people can continue to reply to my questions with various forms of the reply, "Why are you asking this question," those replies do not lead toward any further knowledge about the power consumed by the supercharger as a percentage of the total power produced by the Verado.

The more people keep replying to my question with no answers, but instead want to change the topic, the more convinced I become that either

--these people do not know the answer, or

--if they do know the answer, they are extraordinarily reluctant to reveal the answer

If we assume the first case, they don't know the answer, then I don't see much point in their continuing participation.

If we assume the second case, they do know the answer, perhaps they would just give their answer. In that way, we could continue to discussion.

Some people have, almost from the instant I began this topic, spent more time on trying to ascribe some motivation to the inquiry than they have on the inquiry, its data, or to any analysis of the data. When I began my survey I had no idea that it would be a survey of a forbidden topic, and that the simple notion of gathering data on the topic would be seen as some sort of suspicious action that must be carefully examined for motive. Since I cannot read other people's minds, and since I really am not interested in learning their motives, I am not going to speculate about why this has happened.

I have just collected some information available directly from manufacturers and organized it, along with making a few simple calculations. If that causes anyone to become suspicious of me, it is unfortunate.

posted 03-19-2014 06:33 PM ET (US)            

Another article discusses E-tec manufacturing and includes a description of the engine test cells used to gather information required by the EPA.

Boating is not the words best magazine but often has some interesting articles.

posted 03-20-2014 06:17 PM ET (US)            

I'm not sure I spelled Rotax correctly. If I did it was luck as I know absolutely nothing about the engines. They are more a mystery to me than the Verados of which I am an owner. Calculating accurate supercharger energy consumption is almost impossible without data unavailable to me. I suspect the Verado supercharger energy consumption is a curve depending upon the work demanded of the engine and the ECU settings.

Butch