Engine HP and Torque rates

Above is a summary of the 200-300hp class, for those interested.

Note the list isn't definitive. Its a bit hard to parse all the model numbers and sometimes there is a bit of weirdness. For example as I mentioned, the drive-by-wire Suzukis have a marginally different output versus the standard mechanical control model (I listed the drive by wire). I also have no idea why the 250 suzuki has more torque than the 300 (I double checked to make sure it wasn't a trascription error)? Likewise, for some reason I couldn't find the 300hp supercharged Verado, just the V8 300, and didn't bother to pull out the Seapros. Also, there are some cases duplicate powerheads with seperate emissions certificates that have marginally different output - there are also a few high output models that I missed.

Anyway, one of the big takeaways (that I think we all know) is that the manufacturers only have a few powerheads that are tuned for several different hp applications. The stated hp generally hits the mark (a knock to the mythical 10% rule), but torque is the big variable. In the 225-300hp class, if you spring for the 300hp model you are getting 33% more power however in a lot of cases you aren't getting much more torque. For example the Mercury 300 V8 only gets 9% more torque than the 225 V8. Likewise, there are also some crossover models such as the Suzuki 250 (3.6L vs 4.0L), and the Mercury 225 (3.4L vs 4.6L) which aren't even remotely comparable to eachother in terms of torque.

I always think that if you can bump up into the next powerhead class, you are going to get a lot of bang for your buck, whereas the highest output models from a particular powerhead may not feel that much stronger (holeshot, ability to hold constant speed at cruise), and the difference would mainly show up at WOT.

Anyway, interesting stuff. Please feel free to post corrections or additional info.
 
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macro said:
Would the best motor be the one with the most torque at the lowest rpm? Warranty/weight/fuel burn/reliability aside?
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I'd say that all those things would be factors. But in order to appreciate how torque/rpm relate to eachother think about how you need to 'access' the power that the motor has available.

Think about the 3.4 & 4.6 Mercury 225. On identical hulls, with identical props, both motors are likely going to have almost identical top speed at WOT. However, if you have 6 people in those same boats and try to pull a big fat waterskier up out of the water, that is where you will appreciate the value of low rpm torque. Once the skier is up, its the same - but how you get there is the difference.

Torque is going to help holeshot, its going to help you stay on plane at low cruising speed (without constantly modulating the throttle), and its going to help you maintain a constant speed in variable seas when you are running into/climbing waves.

I'd also suspect that a high torque motor is going to be less sensitive to being prop'd perfectly under different loads. Think about this with a 9.9hp motor. If all the power is only available when you rev all the way out - what that means is that you have to get on plane first to access the power. Wrong prop, overweight, the motor is going to bog down and never even get into its power band. A high torque motor me be able to power through, and get up on plane, even if it does't have a low pitch prop.
 
Every engine has torque and h.p. curves. There is no substitute for torque. I rarely run up into the higher rpm range for full, rated h.p. so that possibility does me little good. If an engine can produce it's highest torque in the 3200 to 3800 rpm range , I could care less what the h.p. rating is. I look at the torque curve.,If additional torque allows the use of a larger diameter prop, that's even better. Of course, I'm not running a ski boat, either.
 
Here's a crazy one: I've got a 2019 Evinrude 135HO. I've always heard that the HO's were really popular because of the 10% rule (meaning that the stated hp was intentionally downplayed, and its actually closer to 150). The emissions certificate dispels that myth. It tests at bang on 100kw / 134hp - however, peak torque is 277.2n-m @ only 3250rpm! Remember the Suzuki 140hp model at 168 n-m... In terms of torque the 135 Evinrude is greater than even the Yamaha and Suzuki 200hp models.

This totally checks out with my experience of the motor. This thing could pull a stump out of the water, and under hard acceleration from a stand still, the engine is immediately in its power band and the prop spins so hard that you can feel it cavitating (but goes away once the speed settles out). While it really shines at about 0-30mph, the top end (above 4000rpm) is great - but nothing compared to the low end grunt. Would love to see a torque/hp curve, but you-get-what-you-get.

Same thing holds true with the 200-250HO models, they are punching up with torque well into the range of 300hp 4-strokes.

As a side note, if you want to search previous years - just change the year in the URL and it seems to work.
 
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Max123 said:
Here's a crazy one: I've got a 2019 Evinrude 135HO. I've always heard that the HO's were really popular because of the 10% rule (meaning that the stated hp was intentionally downplayed, and its actually closer to 150). The emissions certificate dispels that myth. It tests at bang on 100kw / 134hp - however, peak torque is 277.2n-m @ only 3250rpm! Remember the Suzuki 140hp model at 168 n-m... In terms of torque the 135 Evinrude is greater than even the Yamaha and Suzuki 200hp models.

This totally checks out with my experience of the motor. This thing could pull a stump out of the water, and under hard acceleration from a stand still, the engine is immediately in its power band and the prop spins so hard that you can feel it cavitating (but goes away once the speed settles out). While it really shines at about 0-30mph, the top end (above 4000rpm) is great - but nothing compared to the low end grunt. Would love to see a torque/hp curve, but you-get-what-you-get.

Same thing holds true with the 200-250HO models, they are punching up with torque well into the range of 300hp 4-strokes.

As a side note, if you want to search previous years - just change the year in the URL and it seems to work.
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Does this type of performance place a significant increase strain on the machine in a detrimental way or are they built to withstand it?
 
Skins88 said:
2012. Maybe I wasn't reading it right...
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The mercury data is not quite as clear as they use the actual technical model designation rather than the common description.

Here's what I found for 2012:

Model 1250V23KD (I think this is a 250 Verado).
Displacement 2598cc / 184kw (246.7hp) / peak torque 366n-m @ 4750rpm

Stacks up where you would expect. Not quite as much torque as the big displacement Mercury V8 250, but stronger than the naturally aspirated Suzuki 3.6 250. Supercharged engines are always going to punch above their weight/displacement, but it depends on how the supercharger is tuned/geared (either low end grunt or added top end, but typically not both)
 
MikePA said:
Does this type of performance place a significant increase strain on the machine in a detrimental way or are they built to withstand it?
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100%. Torque = 'twist' = more stress on your transom. My boat is rated for 200hp.
 
Gallivanter said:
I have a 200 Zuke 4 cylinder on my 22 footer, the fuel economy, holeshot torque, overall performance is fantastic, couldn’t be happier. 30 MPH at 4300 rpm, gets the family around nicely. Definitely not disappointed
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This is so interesting. We have twin 200 Suzuki's (fly-by-wires) on our boat and I always felt that the motors ran best right around 4000 RPM in perfect water.

You know that sound and the feel of the hull in the water when you just know that the boat, the motors, everything is in harmony.

Thanks for starting this thread.
 
Max123 said:
Here's a crazy one: I've got a 2019 Evinrude 135HO. I've always heard that the HO's were really popular because of the 10% rule (meaning that the stated hp was intentionally downplayed, and its actually closer to 150). The emissions certificate dispels that myth. It tests at bang on 100kw / 134hp - however, peak torque is 277.2n-m @ only 3250rpm! Remember the Suzuki 140hp model at 168 n-m... In terms of torque the 135 Evinrude is greater than even the Yamaha and Suzuki 200hp models.

This totally checks out with my experience of the motor. This thing could pull a stump out of the water, and under hard acceleration from a stand still, the engine is immediately in its power band and the prop spins so hard that you can feel it cavitating (but goes away once the speed settles out). While it really shines at about 0-30mph, the top end (above 4000rpm) is great - but nothing compared to the low end grunt. Would love to see a torque/hp curve, but you-get-what-you-get.

Same thing holds true with the 200-250HO models, they are punching up with torque well into the range of 300hp 4-strokes.

As a side note, if you want to search previous years - just change the year in the URL and it seems to work.
Click to expand...
Big a.. chainsaw with a prop at the end 😂😂
 
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