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Author Topic:   E-TEC Mid-range Gap

jimh posted 12-24-2005 11:11 AM ET (US)
Because of rising prices, fuel economy has become a prime consideration in engine choice. There are two competing engine technologies on the market: two-stroke direct injection and four-stroke port injection. We look for information where we can compare the fuel consumption of these two technologies.
Although not a perfect comparison, the 150-HP outboard has been tested on very similar boats and the results published on-line. Using a 17-foot aluminum fishing boat, we can compare the Evinrude E-TEC 150 to the Yahama F-150. Here are the data sources:
Yamaha F-150
Evinrude E-TEC 150
The data are not perfect. There are three uncontrolled variables. First, different propeller are used on the two engines. This very likely has affected the results, as every propeller has its own characteristic efficiency at moving the boat. Second, the boats were not quite identical in weight, however they are believed to be quite similar. Third, the air temperature was a rather cool 63° during the test of the four-stroke motor, while the two-stroke was tested at 80°. This may also have influenced the fuel efficiency of the motors.
Studying the results with special attention to fuel consumption, there appears to be a noticeable mid-range fuel consumption gap between these two engines. To more clearly show this, we plot the relationship between fuel consumption and boat speed.

Some comments about the graph itself are in order. First, this is a very accurate plotting of the data. I mention this because there is a very unfortunate tendency these days in graphical presentations to accept very sloppy plots of the data as produced by a certainly spreadsheet application whose graphing output is particularly awful when it comes to making cartesian coordinate plots. The curves that result on those inaccurate plots have a tendency to obscure data or promote a false interpretation because of the inaccurate shapes of the curves. Next, I think the notion of plotting the boat speed as a function of the fuel burn rate has some interesting characteristics. Typically one sees plots of other performance data, usually boat speed as a function of engine speed. However, ultimately what makes the boat go forward is the combustion of some gasoline or other fuel. In this plot we look at the rate which the boat goes forward as a function of the rate at which it burns fuel. Well, enough on the graph per se, let us look at the data.
This plot clearly shows there is a noticeable difference in the curve in the mid-range speed region of about 15 to 35-MPH. This is what I call the E-TEC Mid-range Gap. This warrants some further study. I would like to locate additional head-to-head tests between E-TEC motors and four-stroke motors to compare them in this way. Suggestions for other sources of test data are welcome. Also, it would be quite interesting to add the supercharged Verado four-stroke to this analysis. The principal obstacle is finding comparative test data.

derf posted 12-24-2005 12:14 PM ET (US)
Because of the nature of the different systems, 2- vs 4-stroke, a different prop would probably be necessary to achieve similar results.
That little jump at the end by the Etec is interesting. How do the MPH/RPM ranges and ideal WOT RPM numbers compare? Gearing and prop pitch would be ways to compensate for differing characteristics of the 2- vs 4-stroke systems.
You could analyze this to death. The best test would be to get two like hulls and mount an Etec on one and a 4-stroke on the other. Then, by trial and error, find out which prop performs best on each rig. Then compare each with it's own ideal prop. I think it will be a toss-up with the Etec being better suited to certain apps/RPM ranges and the 4-stroke having different advantages. I think it will be as usual, a compromise.
I'm glad that someone has embraced the viability of high tech 2-strokes. With marketing, government regs, and hype driving most corporations, I'm surprised that everyone didn't just abandon 2-strokes. I think 2-stokes are better suited to outboard applications than 4-stokes because of they are simpler, have fewer moving parts, and proven.
Now, diesel outboards should get the same high tech attention that 4-strokes and 2-strokes have gotten lately. That would be interesting, indeed.
jimh posted 12-24-2005 02:08 PM ET (US)
I am leaving engine speed entirely out of this comparison. As far as I see, the engine speed is not important at all. This is a look at how efficiently the system converts fuel to boat movement. That is the definition of miles per gallon. Instead of just looking at a single number as saying this is the miles-per-gallon, here we can see how the two different engines compare at different rates of consumption.
jimh posted 12-24-2005 02:14 PM ET (US)
I found a comparison between the E-TEC and another four-stroke, this time a VERADO. The source of the data is:
http://www.e-tecinfonet.org/sitebuildercontent/sitebuilderfiles/pe309a. pdf
but this report acknowledges BASS & WALLEYE BOAT magazine as the testers.
This is quite an interesting comparison. Here we see a huge gap in the performance, and solidly in favor of the E-TEC. There is a very small mid-range cruise speed segment where the VERADO is more efficient, but once the boat speed gets above 40-MPH, there is a significant advantage to the E-TEC. Again, this test data is from a Bass Boat, so perhaps not of interest to all Boston Whaler owners, as we seldom run at those speeds.

It would be interesting to see these two motors compared on a hull where the speed potential was more like a Boston Whaler, that is, down in the 30 to 40-MPH range. However, you can make the assumption that in order to push a bigger hull to those slower speeds, the engines would be burning fuel at similar rates. Thus this comparison may have some validity.
JayR posted 12-24-2005 02:29 PM ET (US)
Now if we could only convince LHG to go ahead and get that Verado for his Ribbed Outrage. With my soon to be E-TEC powered Ribbed Outrage we could put these questions to rest.
Good timing on presenting this data Jim. Larry is on vacation, isn't he??? Hahaha.
jimh posted 12-24-2005 02:54 PM ET (US)
Here is the fuel burn data from the recent 200-HP shoot-out in BASS & WALLEYE BOAT magazine. The source data for this is currently not available on-line. This plot shows another significant gap between the E-TEC and other two-stroke engines in terms of fuel consumption. This data has the most dramatic difference, which sparked a great deal of discussion.
Again, this test was on a high-speed bass boat.For a lengthy thread which focuses on these test results, see:
200-HP Two-Stroke DFI Magazine Test
http://continuouswave.com/ubb/Forum4/HTML/004039.html
jimh posted 12-24-2005 02:58 PM ET (US)
So far the results look something like a game of scissors-paper-rock. There are situations where the E-TEC is the winner and situations where it is the loser. Compared to the VERADO it is more efficient fuel burner, but compared to the OptiMax or HPDI it is less efficient. Compared to a naturally-aspirated four-stroke it is a close match, except for a small mid-range gap.
Peter James Morgan posted 12-26-2005 02:57 PM ET (US)
Propellers and engine set-up, particularly height and set-back, play such a huge part in the performance of any given outboard, that IMHO the only fair comparison would be to test with identical height and set-back on identical hulls, side by side, with propellers from the same family from the same manufacturer -- probably Mercury, as Merc's props are generally acknowledged as being superior.
Even better would be to test the motors on a dyno. That way all variables other than the powerhead could be eliminated!
Despite all this, let's not forget that what is important is not just the fuel consumption, but the overall cost of running a boat. Repairs and maintenance costs are more than likely much more important than actual fuel consumption.
And let's not forget that we go boating to have fun. An outboard must be enjoyable to use!
Peter posted 12-26-2005 03:19 PM ET (US)
PJM, you beat me to it as I was going to make the same comments. The Evinrude E-TEC 150 is mounted in the 3rd hole up whereas the Yamaha F150 is mounted in the 2nd hole up. Thus the Evinrude is mounted higher than the Yamaha. Higher mounting will improve speed at WOT (note the Evinrude was about 4 MPH faster) but probably at the cost of low end traction because less propeller is in the water.
I ran the same 14 1/2 x 20 Raker propeller on my 18 Outrage. I tried it two holes up and one hole up. There was a noticible difference in mid-range traction and WOT speed between the two mounting heights. I opted to stick with running the motor at the lower height to increase the mid-range traction at the expense of the WOT speed.
Without eliminating all of the variables that there are in these two tests, its hard to conclude that there is actually a gap in mid-range fuel consumption by the powerheads for a given mid-range HP output or that we are seeing mid-range performance differences caused by the different rigging (height, props, loading, particular boat running characteristics). Dyno testing would certainly help reveal powerhead fuel consumption per output differences, if any, but even those can be a off.
Tollyfamily posted 12-27-2005 12:44 PM ET (US)
Anyone else notice the high fuel burn for the Verado on that link? It seems most new outboards burn 8-9% of their hp per hour at full throttle and the Merc is 27.2 gph for the 250. I drag race and the blower cars have to run a much richer mixture to avoid detonation and it looks like the supercharged outboard is doing the same thing.
Dan

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Author	Topic: E-TEC Mid-range Gap
jimh	posted 12-24-2005 11:11 AM ET (US) Because of rising prices, fuel economy has become a prime consideration in engine choice. There are two competing engine technologies on the market: two-stroke direct injection and four-stroke port injection. We look for information where we can compare the fuel consumption of these two technologies. Although not a perfect comparison, the 150-HP outboard has been tested on very similar boats and the results published on-line. Using a 17-foot aluminum fishing boat, we can compare the Evinrude E-TEC 150 to the Yahama F-150. Here are the data sources: Yamaha F-150 Evinrude E-TEC 150 The data are not perfect. There are three uncontrolled variables. First, different propeller are used on the two engines. This very likely has affected the results, as every propeller has its own characteristic efficiency at moving the boat. Second, the boats were not quite identical in weight, however they are believed to be quite similar. Third, the air temperature was a rather cool 63° during the test of the four-stroke motor, while the two-stroke was tested at 80°. This may also have influenced the fuel efficiency of the motors. Studying the results with special attention to fuel consumption, there appears to be a noticeable mid-range fuel consumption gap between these two engines. To more clearly show this, we plot the relationship between fuel consumption and boat speed. Some comments about the graph itself are in order. First, this is a very accurate plotting of the data. I mention this because there is a very unfortunate tendency these days in graphical presentations to accept very sloppy plots of the data as produced by a certainly spreadsheet application whose graphing output is particularly awful when it comes to making cartesian coordinate plots. The curves that result on those inaccurate plots have a tendency to obscure data or promote a false interpretation because of the inaccurate shapes of the curves. Next, I think the notion of plotting the boat speed as a function of the fuel burn rate has some interesting characteristics. Typically one sees plots of other performance data, usually boat speed as a function of engine speed. However, ultimately what makes the boat go forward is the combustion of some gasoline or other fuel. In this plot we look at the rate which the boat goes forward as a function of the rate at which it burns fuel. Well, enough on the graph per se, let us look at the data. This plot clearly shows there is a noticeable difference in the curve in the mid-range speed region of about 15 to 35-MPH. This is what I call the E-TEC Mid-range Gap. This warrants some further study. I would like to locate additional head-to-head tests between E-TEC motors and four-stroke motors to compare them in this way. Suggestions for other sources of test data are welcome. Also, it would be quite interesting to add the supercharged Verado four-stroke to this analysis. The principal obstacle is finding comparative test data.
derf	posted 12-24-2005 12:14 PM ET (US) Because of the nature of the different systems, 2- vs 4-stroke, a different prop would probably be necessary to achieve similar results. That little jump at the end by the Etec is interesting. How do the MPH/RPM ranges and ideal WOT RPM numbers compare? Gearing and prop pitch would be ways to compensate for differing characteristics of the 2- vs 4-stroke systems. You could analyze this to death. The best test would be to get two like hulls and mount an Etec on one and a 4-stroke on the other. Then, by trial and error, find out which prop performs best on each rig. Then compare each with it's own ideal prop. I think it will be a toss-up with the Etec being better suited to certain apps/RPM ranges and the 4-stroke having different advantages. I think it will be as usual, a compromise. I'm glad that someone has embraced the viability of high tech 2-strokes. With marketing, government regs, and hype driving most corporations, I'm surprised that everyone didn't just abandon 2-strokes. I think 2-stokes are better suited to outboard applications than 4-stokes because of they are simpler, have fewer moving parts, and proven. Now, diesel outboards should get the same high tech attention that 4-strokes and 2-strokes have gotten lately. That would be interesting, indeed.
jimh	posted 12-24-2005 02:08 PM ET (US) I am leaving engine speed entirely out of this comparison. As far as I see, the engine speed is not important at all. This is a look at how efficiently the system converts fuel to boat movement. That is the definition of miles per gallon. Instead of just looking at a single number as saying this is the miles-per-gallon, here we can see how the two different engines compare at different rates of consumption.
jimh	posted 12-24-2005 02:14 PM ET (US) I found a comparison between the E-TEC and another four-stroke, this time a VERADO. The source of the data is: http://www.e-tecinfonet.org/sitebuildercontent/sitebuilderfiles/pe309a. pdf but this report acknowledges BASS & WALLEYE BOAT magazine as the testers. This is quite an interesting comparison. Here we see a huge gap in the performance, and solidly in favor of the E-TEC. There is a very small mid-range cruise speed segment where the VERADO is more efficient, but once the boat speed gets above 40-MPH, there is a significant advantage to the E-TEC. Again, this test data is from a Bass Boat, so perhaps not of interest to all Boston Whaler owners, as we seldom run at those speeds. It would be interesting to see these two motors compared on a hull where the speed potential was more like a Boston Whaler, that is, down in the 30 to 40-MPH range. However, you can make the assumption that in order to push a bigger hull to those slower speeds, the engines would be burning fuel at similar rates. Thus this comparison may have some validity.
JayR	posted 12-24-2005 02:29 PM ET (US) Now if we could only convince LHG to go ahead and get that Verado for his Ribbed Outrage. With my soon to be E-TEC powered Ribbed Outrage we could put these questions to rest. Good timing on presenting this data Jim. Larry is on vacation, isn't he??? Hahaha.
jimh	posted 12-24-2005 02:54 PM ET (US) Here is the fuel burn data from the recent 200-HP shoot-out in BASS & WALLEYE BOAT magazine. The source data for this is currently not available on-line. This plot shows another significant gap between the E-TEC and other two-stroke engines in terms of fuel consumption. This data has the most dramatic difference, which sparked a great deal of discussion. Again, this test was on a high-speed bass boat.For a lengthy thread which focuses on these test results, see: 200-HP Two-Stroke DFI Magazine Test http://continuouswave.com/ubb/Forum4/HTML/004039.html
jimh	posted 12-24-2005 02:58 PM ET (US) So far the results look something like a game of scissors-paper-rock. There are situations where the E-TEC is the winner and situations where it is the loser. Compared to the VERADO it is more efficient fuel burner, but compared to the OptiMax or HPDI it is less efficient. Compared to a naturally-aspirated four-stroke it is a close match, except for a small mid-range gap.
Peter James Morgan	posted 12-26-2005 02:57 PM ET (US) Propellers and engine set-up, particularly height and set-back, play such a huge part in the performance of any given outboard, that IMHO the only fair comparison would be to test with identical height and set-back on identical hulls, side by side, with propellers from the same family from the same manufacturer -- probably Mercury, as Merc's props are generally acknowledged as being superior. Even better would be to test the motors on a dyno. That way all variables other than the powerhead could be eliminated! Despite all this, let's not forget that what is important is not just the fuel consumption, but the overall cost of running a boat. Repairs and maintenance costs are more than likely much more important than actual fuel consumption. And let's not forget that we go boating to have fun. An outboard must be enjoyable to use!
Peter	posted 12-26-2005 03:19 PM ET (US) PJM, you beat me to it as I was going to make the same comments. The Evinrude E-TEC 150 is mounted in the 3rd hole up whereas the Yamaha F150 is mounted in the 2nd hole up. Thus the Evinrude is mounted higher than the Yamaha. Higher mounting will improve speed at WOT (note the Evinrude was about 4 MPH faster) but probably at the cost of low end traction because less propeller is in the water. I ran the same 14 1/2 x 20 Raker propeller on my 18 Outrage. I tried it two holes up and one hole up. There was a noticible difference in mid-range traction and WOT speed between the two mounting heights. I opted to stick with running the motor at the lower height to increase the mid-range traction at the expense of the WOT speed. Without eliminating all of the variables that there are in these two tests, its hard to conclude that there is actually a gap in mid-range fuel consumption by the powerheads for a given mid-range HP output or that we are seeing mid-range performance differences caused by the different rigging (height, props, loading, particular boat running characteristics). Dyno testing would certainly help reveal powerhead fuel consumption per output differences, if any, but even those can be a off.
Tollyfamily	posted 12-27-2005 12:44 PM ET (US) Anyone else notice the high fuel burn for the Verado on that link? It seems most new outboards burn 8-9% of their hp per hour at full throttle and the Merc is 27.2 gph for the 250. I drag race and the blower cars have to run a much richer mixture to avoid detonation and it looks like the supercharged outboard is doing the same thing. Dan