E-TEC 25-HP v. E-TEC 30-HP - Moderated Discussion Areas

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Author Topic:   E-TEC 25-HP v. E-TEC 30-HP

Utik posted 09-23-2011 07:09 AM ET (US)
I am in the market for a new motor. [What is] the difference between the power level of the 25-HP and 30-HP E-TEC? I have heard from several people that there is absolutely no difference in power between these motors. I am almost certain that this is true at the low end and mid range, but I am curious about the top end. Given the ten-percent leeway that manufacturers are allowed on power ratings, the 25 could be as much as 27.5-HP and the 30 could be as little as 27-HP. It is entirely possible that they make the same power and still meet the rating requirement. Top end is important to me, but I think the 30 is about $800 dollars more than the 25. I would be willing to spend this if I really thought I was getting something for the money. On the other hand, I absolutely hate the thought of paying $800 for a different decal on the motor cover.
I notice that Evinrude does not publish any performance reports on the 25 and 30 where the motors are run on the same boat. I don't usually go in for conspiracy theories, but I have to admit that this does make me a bit suspicious.
Anybody with any thoughts or experience with this? Do any of you who may have put a 25 or 30 E-TEC on a Whaler 13 have GPS speed measurements we can compare here?

contender posted 09-23-2011 09:57 AM ET (US)
If there is no difference then why does Evinrude market and make a 25 and a 30 hp engine? Your 30 hp will come in handy with any extra weight in the boat or if your kids want to ski or tow a tube. If the money is not the issue I would not think twice about it. I feel that a 30 hp is the best all round engine for a 13 whaler...good luck to you
Tohsgib posted 09-23-2011 11:08 AM ET (US)
2 things. If you get the 25 and it is not up to snuff you will regret not getting the 30. 2)resale will be much better. It is probably just a bit of ECM mapping. Problem might not be the 5hp, it is most likely prop choices.
Utik posted 09-23-2011 03:00 PM ET (US)
Tohsgib,I don't know what line of work you are in, but if if it's not mindreading, you might want to reconsider your carrier choice. :-)
The 2 things you list are exactly what I am thinking and probably enough to drive me into the 30.
I just wanted to see if I could find some way to get a direct comparison of the 2 motors on the same boat.
Tohsgib posted 09-23-2011 03:18 PM ET (US)
Couple people just repowered with the 30 over the 25, maybe they will chime in.
Tohsgib posted 09-24-2011 10:35 AM ET (US)
Maybe not!
jimh posted 09-25-2011 08:58 AM ET (US)

quote:
Given the ten-percent leeway that manufacturers are allowed on power ratings...
What is the basis for this assumption? There is a ten-percent manufacturing tolerance permitted. Any particular engine coming off the assembly line coulhd vary from the rated power by as much as ten-percent. There are constraints on the rated power, but only that the rated power is recommended to be within six-percent of the peak power that occurs in the recommended operating range. See
http://continuouswave.com/whaler/reference/ICOMIA28-83.html

jimh posted 09-25-2011 09:01 AM ET (US)
In engines which are otherwise identical except for horsepower rating, the higher rated horsepower engine often obtains the added horsepower by being able to accelerate the engine to higher engine speeds. Horsepower is often proportional to engine speed, so a higher engine speed produces more peak horsepower. You will not see much difference in the engines until you are in the upper portion of the engine speed range.
pcrussell50 posted 09-25-2011 08:39 PM ET (US)
Using higher rpm to make up the difference is the only thing that makes any sense if the two motors are otherwise identical.
We had a thread started a while back that asked specifically what could be done through the ECM (besides rpm), to cause different horsepower ratings in otherwise identical motors... it was inconclusive, to say the least. Some interesting ideas were kicked around though, like intentional misfirings, spaced in such a way as to be undetectable.
-Peter
Utik posted 10-05-2011 07:29 AM ET (US)
According to BRP, they both make their peak HP at the same RPM of 5,500. That is exactly what has me puzzled. It is also why I am interested in trying to find the relative performance on the same boat.
dgoodhue posted 10-05-2011 08:41 AM ET (US)
I haven't seen any top speed data for 25hp e-tec but the 13's with 30 e-tec have a higher top speed than is what is typical for 25 on 13' classic whaler and seems to fall online for an expected speed for 30hp.
Agntvbb posted 10-10-2011 05:25 PM ET (US)
I get just over 30mph with my Etec on a 13 with two adults kid and gear. I got about 35 with the 40. I don't know about the 25, you might not be able to get tilt/trim?
Agntvbb posted 10-11-2011 12:13 AM ET (US)
Checked the specs on the 25, power tilt is available. Weight is almost identical between 25 and 30 with the tilt trim, ~184 lbs. I guess from a performance perspective if you could get 5HP extra at the same weight, why not.
If you are going all the way stripped down, nothing but the thwarts, and tiller controls, rope start only, the 13 would rock with 25hp, but put a passenger in there and gear, the extra ooph will be welcome
I'm pretty sure, by myself in the boat I would get 31-33 mph, but experience wise, the difference between 40 and 30 hp is pretty indistinguishable.
The Etec is a joy to run, quiet, the fuel efficiency is remarkable, basically smoke and odor free, and the white model looks great on the boat. It's a great engine.
Utik posted 10-11-2011 02:46 PM ET (US)
I completely agree that if you get 5 extra HP at the same weight, it is a good thing. What I am trying to determine is, do you really get 5 extra HP or do you just get different decals.
Agntvbb posted 10-11-2011 11:27 PM ET (US)
The spec of plus or minus 10% can work for or against you. With the 30 you are buying 27-33 HP. With the 25 you are buying 22.5-27.5 HP. I would also bet that in this day and age of 6 sigma manufacturing the odds of you finding an engine that bumps up against the tail end of the bell curve of the spec on either end are exceedingly long. The vast majority of motors are probably dead on spec. Most modern quality control can deliver 99.999% of units within spec with 99.9% being within one standard deviation of the spec. The odds of you finding that one in a million motor that is close to the upper limit of a spec without exceeding it are extremely long.
You are over-thinking it, If you want a 30 HP, buy a 30 HP.
Peter posted 10-12-2011 07:41 AM ET (US)
I agree with the over thinking. If you think that Evinrude really just applies 30 HP stickers to the cowl and charges $800 for those stickers, then you should have the same concerns for the other makers who offer both a 25 and 30 HP model, namely Honda and Mercury. Their 25 and 30 HP motors are built on the same block just like the E-TEC 25 and 30s. Mercury does not provide performance reports for the 25 and 30 on the same boat. Honda provides NO performance reports at all for either motor. They are all conspiring together.
The difference between a 25 and 30 (any brand) on the 13 foot Whaler will come down to the propeller pitch. The 30 HP model should be able to twist a propeller with at least 1 inch greater pitch than the 25 HP model to the same recommended WOT RPM. I suspect that the two models will not be noticibly different from each other except in the last 500 RPM of the WOT operating range where the 30 HP model will be permitted to inject up to 0.5 GPH more fuel whereas the 25 HP will be "goverened".
If you run your 13 foot Whaler more than 30 percent of the the time at WOT, get the 30. If you don't, get the 25. I know that when I had my 13 foot Whaler many years ago, I ran it more than 30 percent of the time at WOT so I would get the 30.

Utik posted 10-12-2011 08:51 AM ET (US)
I agree with everything you are saying. Especially the part about me over thinking this. Isn't that what these internet forums are for? :-)
I am leaning heavily toward the 30. In fact I am virtually certain to get the 30 for reasons noted above. I just find it fun to kick this stuff around a bit.
You make the point about the power likely being the same at the low and midrange RPM points. I feel very strongly that you are right about that. I suspect as you do that any difference is at the top of the RPM band.
You mention the extra fuel use at the top end of the 30. That gave me an idea. I averaged the WOT fuel consumption of the 25 and 30 based on the data available in the BRP published performance reports. The results are interesting.
The average(mean) on the 25 hp was 2.63GPH
The average(mean) on the 30 hp was 2.82GPH
This is a differnce of .19GPH or 6.7% difference.
The average(median) on the 25 hp was 2.57GPH
The average(median) on the 30 hp was 2.65GPH
This is a differnce of .08GPH or 3% difference.
If the HP gain is linear to the fuel consumption increase, and we used the greater difference shown by the mean, the 30 would be producing only 6.7% more power than the 25 or 26.68 hp.
And you thought I was over thinking it before!
jimh posted 10-12-2011 08:59 AM ET (US)
Utik's analysis of the fuel flow data is very interesting. However, we should not expect that the higher horsepower engine would always consume more fuel than the lower horsepower engine. The fuel consumption of the two engines should be identical over most of the engine operating range, and the difference should occur only when the higher-rated engine begins to produce the added horsepower it is capable of making. Because of this, the averaged overall fuel flow data would not show a directly linear relationship, that is, the engine with 20-percent more horsepower should not show a 20-percent greater consumption of fuel. The higher-rated engine should consume 20-percent more fuel only when it is producing the extra horsepower.
Peter posted 10-12-2011 09:18 AM ET (US)
You are on the right track in thinking but there are so many uncontrolled variables that I think its impossible to get that precise. Also, the sample size really isn't big enough.
Utik posted 10-12-2011 09:56 AM ET (US)
jimh, the averages I did were all based on the fuel flow at full power. I just picked the maximum flow for each motor on each boat for my averages.
Peter, I suspect you are right that the sample is too small to get meaningful resuts. There were only 4 tests on the 25hp and 5 tests on the 30hp. With engines this small and such low fuel flow rates the variables and margin for error are probably too great to draw any conclusions.

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Author	Topic: E-TEC 25-HP v. E-TEC 30-HP
Utik	posted 09-23-2011 07:09 AM ET (US) I am in the market for a new motor. [What is] the difference between the power level of the 25-HP and 30-HP E-TEC? I have heard from several people that there is absolutely no difference in power between these motors. I am almost certain that this is true at the low end and mid range, but I am curious about the top end. Given the ten-percent leeway that manufacturers are allowed on power ratings, the 25 could be as much as 27.5-HP and the 30 could be as little as 27-HP. It is entirely possible that they make the same power and still meet the rating requirement. Top end is important to me, but I think the 30 is about $800 dollars more than the 25. I would be willing to spend this if I really thought I was getting something for the money. On the other hand, I absolutely hate the thought of paying $800 for a different decal on the motor cover. I notice that Evinrude does not publish any performance reports on the 25 and 30 where the motors are run on the same boat. I don't usually go in for conspiracy theories, but I have to admit that this does make me a bit suspicious. Anybody with any thoughts or experience with this? Do any of you who may have put a 25 or 30 E-TEC on a Whaler 13 have GPS speed measurements we can compare here?
contender	posted 09-23-2011 09:57 AM ET (US) If there is no difference then why does Evinrude market and make a 25 and a 30 hp engine? Your 30 hp will come in handy with any extra weight in the boat or if your kids want to ski or tow a tube. If the money is not the issue I would not think twice about it. I feel that a 30 hp is the best all round engine for a 13 whaler...good luck to you
Tohsgib	posted 09-23-2011 11:08 AM ET (US) 2 things. If you get the 25 and it is not up to snuff you will regret not getting the 30. 2)resale will be much better. It is probably just a bit of ECM mapping. Problem might not be the 5hp, it is most likely prop choices.
Utik	posted 09-23-2011 03:00 PM ET (US) Tohsgib,I don't know what line of work you are in, but if if it's not mindreading, you might want to reconsider your carrier choice. :-) The 2 things you list are exactly what I am thinking and probably enough to drive me into the 30. I just wanted to see if I could find some way to get a direct comparison of the 2 motors on the same boat.
Tohsgib	posted 09-23-2011 03:18 PM ET (US) Couple people just repowered with the 30 over the 25, maybe they will chime in.
Tohsgib	posted 09-24-2011 10:35 AM ET (US) Maybe not!
jimh	posted 09-25-2011 08:58 AM ET (US) quote: Given the ten-percent leeway that manufacturers are allowed on power ratings... What is the basis for this assumption? There is a ten-percent manufacturing tolerance permitted. Any particular engine coming off the assembly line coulhd vary from the rated power by as much as ten-percent. There are constraints on the rated power, but only that the rated power is recommended to be within six-percent of the peak power that occurs in the recommended operating range. See http://continuouswave.com/whaler/reference/ICOMIA28-83.html
jimh	posted 09-25-2011 09:01 AM ET (US) In engines which are otherwise identical except for horsepower rating, the higher rated horsepower engine often obtains the added horsepower by being able to accelerate the engine to higher engine speeds. Horsepower is often proportional to engine speed, so a higher engine speed produces more peak horsepower. You will not see much difference in the engines until you are in the upper portion of the engine speed range.
pcrussell50	posted 09-25-2011 08:39 PM ET (US) Using higher rpm to make up the difference is the only thing that makes any sense if the two motors are otherwise identical. We had a thread started a while back that asked specifically what could be done through the ECM (besides rpm), to cause different horsepower ratings in otherwise identical motors... it was inconclusive, to say the least. Some interesting ideas were kicked around though, like intentional misfirings, spaced in such a way as to be undetectable. -Peter
Utik	posted 10-05-2011 07:29 AM ET (US) According to BRP, they both make their peak HP at the same RPM of 5,500. That is exactly what has me puzzled. It is also why I am interested in trying to find the relative performance on the same boat.
dgoodhue	posted 10-05-2011 08:41 AM ET (US) I haven't seen any top speed data for 25hp e-tec but the 13's with 30 e-tec have a higher top speed than is what is typical for 25 on 13' classic whaler and seems to fall online for an expected speed for 30hp.
Agntvbb	posted 10-10-2011 05:25 PM ET (US) I get just over 30mph with my Etec on a 13 with two adults kid and gear. I got about 35 with the 40. I don't know about the 25, you might not be able to get tilt/trim?
Agntvbb	posted 10-11-2011 12:13 AM ET (US) Checked the specs on the 25, power tilt is available. Weight is almost identical between 25 and 30 with the tilt trim, ~184 lbs. I guess from a performance perspective if you could get 5HP extra at the same weight, why not. If you are going all the way stripped down, nothing but the thwarts, and tiller controls, rope start only, the 13 would rock with 25hp, but put a passenger in there and gear, the extra ooph will be welcome I'm pretty sure, by myself in the boat I would get 31-33 mph, but experience wise, the difference between 40 and 30 hp is pretty indistinguishable. The Etec is a joy to run, quiet, the fuel efficiency is remarkable, basically smoke and odor free, and the white model looks great on the boat. It's a great engine.
Utik	posted 10-11-2011 02:46 PM ET (US) I completely agree that if you get 5 extra HP at the same weight, it is a good thing. What I am trying to determine is, do you really get 5 extra HP or do you just get different decals.
Agntvbb	posted 10-11-2011 11:27 PM ET (US) The spec of plus or minus 10% can work for or against you. With the 30 you are buying 27-33 HP. With the 25 you are buying 22.5-27.5 HP. I would also bet that in this day and age of 6 sigma manufacturing the odds of you finding an engine that bumps up against the tail end of the bell curve of the spec on either end are exceedingly long. The vast majority of motors are probably dead on spec. Most modern quality control can deliver 99.999% of units within spec with 99.9% being within one standard deviation of the spec. The odds of you finding that one in a million motor that is close to the upper limit of a spec without exceeding it are extremely long. You are over-thinking it, If you want a 30 HP, buy a 30 HP.
Peter	posted 10-12-2011 07:41 AM ET (US) I agree with the over thinking. If you think that Evinrude really just applies 30 HP stickers to the cowl and charges $800 for those stickers, then you should have the same concerns for the other makers who offer both a 25 and 30 HP model, namely Honda and Mercury. Their 25 and 30 HP motors are built on the same block just like the E-TEC 25 and 30s. Mercury does not provide performance reports for the 25 and 30 on the same boat. Honda provides NO performance reports at all for either motor. They are all conspiring together. The difference between a 25 and 30 (any brand) on the 13 foot Whaler will come down to the propeller pitch. The 30 HP model should be able to twist a propeller with at least 1 inch greater pitch than the 25 HP model to the same recommended WOT RPM. I suspect that the two models will not be noticibly different from each other except in the last 500 RPM of the WOT operating range where the 30 HP model will be permitted to inject up to 0.5 GPH more fuel whereas the 25 HP will be "goverened". If you run your 13 foot Whaler more than 30 percent of the the time at WOT, get the 30. If you don't, get the 25. I know that when I had my 13 foot Whaler many years ago, I ran it more than 30 percent of the time at WOT so I would get the 30.
Utik	posted 10-12-2011 08:51 AM ET (US) I agree with everything you are saying. Especially the part about me over thinking this. Isn't that what these internet forums are for? :-) I am leaning heavily toward the 30. In fact I am virtually certain to get the 30 for reasons noted above. I just find it fun to kick this stuff around a bit. You make the point about the power likely being the same at the low and midrange RPM points. I feel very strongly that you are right about that. I suspect as you do that any difference is at the top of the RPM band. You mention the extra fuel use at the top end of the 30. That gave me an idea. I averaged the WOT fuel consumption of the 25 and 30 based on the data available in the BRP published performance reports. The results are interesting. The average(mean) on the 25 hp was 2.63GPH The average(mean) on the 30 hp was 2.82GPH This is a differnce of .19GPH or 6.7% difference. The average(median) on the 25 hp was 2.57GPH The average(median) on the 30 hp was 2.65GPH This is a differnce of .08GPH or 3% difference. If the HP gain is linear to the fuel consumption increase, and we used the greater difference shown by the mean, the 30 would be producing only 6.7% more power than the 25 or 26.68 hp. And you thought I was over thinking it before!
jimh	posted 10-12-2011 08:59 AM ET (US) Utik's analysis of the fuel flow data is very interesting. However, we should not expect that the higher horsepower engine would always consume more fuel than the lower horsepower engine. The fuel consumption of the two engines should be identical over most of the engine operating range, and the difference should occur only when the higher-rated engine begins to produce the added horsepower it is capable of making. Because of this, the averaged overall fuel flow data would not show a directly linear relationship, that is, the engine with 20-percent more horsepower should not show a 20-percent greater consumption of fuel. The higher-rated engine should consume 20-percent more fuel only when it is producing the extra horsepower.
Peter	posted 10-12-2011 09:18 AM ET (US) You are on the right track in thinking but there are so many uncontrolled variables that I think its impossible to get that precise. Also, the sample size really isn't big enough.
Utik	posted 10-12-2011 09:56 AM ET (US) jimh, the averages I did were all based on the fuel flow at full power. I just picked the maximum flow for each motor on each boat for my averages. Peter, I suspect you are right that the sample is too small to get meaningful resuts. There were only 4 tests on the 25hp and 5 tests on the 30hp. With engines this small and such low fuel flow rates the variables and margin for error are probably too great to draw any conclusions.