My father and I have been debating which engine gives the most power for pulling up a skier. He says 4 stroke has better low end torque while 2 stroke has higher top end. I tell him he has it reversed. Thoughts?
2 stroke vs 4 stroke 115hp
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Similarly sized,a 2 stroke will have more hole shot than a 4 stroke.
You're correct.
You're correct.
Originally Posted By: outoforder
My father and I have been debating which engine gives the most power for pulling up a skier. He says 4 stroke has better low end torque while 2 stroke has higher top end. I tell him he has it reversed. Thoughts?
I have always heard 2 stroke has more torque and I believe it is at the lower end of the rpms. Not sure about the whole range of rpms though.
My father and I have been debating which engine gives the most power for pulling up a skier. He says 4 stroke has better low end torque while 2 stroke has higher top end. I tell him he has it reversed. Thoughts?
I have always heard 2 stroke has more torque and I believe it is at the lower end of the rpms. Not sure about the whole range of rpms though.
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4 strokes have more upper band power. That's what makes them so much fun. Ride a 2 stroke and 4 stroke dirt bike (of same cc) side by side and you'll see what I mean.
So my vote goes to your dad being correct.
So my vote goes to your dad being correct.
All you have to do is look at motorcycle racing to see a practical example of the differences which are more then just torque and horsepower.
No a 2 stroke has a higher Rev limit and makes most power at high revs. Both tq and hp. a 4 stroke makes its power at a much lower rpm. 2 strokes make more power with a smaller displacement than a 4.
Originally Posted By: abycat
No a 2 stroke has a higher Rev limit and makes most power at high revs. Both tq and hp. a 4 stroke makes its power at a much lower rpm. 2 strokes make more power with a smaller displacement than a 4.
agreed. A 4 makes a more linear power. Most 2 strokes rev high, and make more power per CC, however they generally make most of their power and Tq within a certain range of RPM. Generally at the higher end of the RPM range. Most two stroke dirt bikes are all or nothing in my experience.
No a 2 stroke has a higher Rev limit and makes most power at high revs. Both tq and hp. a 4 stroke makes its power at a much lower rpm. 2 strokes make more power with a smaller displacement than a 4.
agreed. A 4 makes a more linear power. Most 2 strokes rev high, and make more power per CC, however they generally make most of their power and Tq within a certain range of RPM. Generally at the higher end of the RPM range. Most two stroke dirt bikes are all or nothing in my experience.
Originally Posted By: donnyj08
Originally Posted By: abycat
No a 2 stroke has a higher Rev limit and makes most power at high revs. Both tq and hp. a 4 stroke makes its power at a much lower rpm. 2 strokes make more power with a smaller displacement than a 4.
agreed. A 4 makes a more linear power. Most 2 strokes rev high, and make more power per CC, however they generally make most of their power and Tq within a certain range of RPM. Generally at the higher end of the RPM range. Most two stroke dirt bikes are all or nothing in my experience.
exactly mine to. a boat motor 2 stroke will be less pronounced than say a 80cc motocross bike but still will hold true.
Originally Posted By: abycat
No a 2 stroke has a higher Rev limit and makes most power at high revs. Both tq and hp. a 4 stroke makes its power at a much lower rpm. 2 strokes make more power with a smaller displacement than a 4.
agreed. A 4 makes a more linear power. Most 2 strokes rev high, and make more power per CC, however they generally make most of their power and Tq within a certain range of RPM. Generally at the higher end of the RPM range. Most two stroke dirt bikes are all or nothing in my experience.
exactly mine to. a boat motor 2 stroke will be less pronounced than say a 80cc motocross bike but still will hold true.
A 2 stroke fires (makes power) on every stroke. A 4 stroke fires every other stroke. That's a 2 strokes biggest advantage.
2 strokes have a sizeable power to weight advantage also.
Comparing a high strung 2 stroke motorcross bike to a modern fuel injected 2 stroke outboard is ridiculous.
I prefer 4 stroke outboards,but in this pulling a skier scenario,a 2 stroke wins.
2 strokes have a sizeable power to weight advantage also.
Comparing a high strung 2 stroke motorcross bike to a modern fuel injected 2 stroke outboard is ridiculous.
I prefer 4 stroke outboards,but in this pulling a skier scenario,a 2 stroke wins.
Originally Posted By: Stewart Fan
A 2 stroke fires (makes power) on every stroke. A 4 stroke fires every other stroke. That's a 2 strokes biggest advantage.
2 strokes have a sizeable power to weight advantage also.
Comparing a high strung 2 stroke motorcross bike to a modern fuel injected 2 stroke outboard is ridiculous.
I prefer 4 stroke outboards,but in this pulling a skier scenario,a 2 stroke wins.
Yes, what he said. I've owned six outboards. Of the six, one was a Johnson J140 (re-badged Suzuki) four stroke. I'll take a two stroke any day. Hp is hp right? The difference is in the hp/tq curves. Check out this video and draw your own conclusions.
https://www.youtube.com/watch?v=Rfm64xkRU3o
A 2 stroke fires (makes power) on every stroke. A 4 stroke fires every other stroke. That's a 2 strokes biggest advantage.
2 strokes have a sizeable power to weight advantage also.
Comparing a high strung 2 stroke motorcross bike to a modern fuel injected 2 stroke outboard is ridiculous.
I prefer 4 stroke outboards,but in this pulling a skier scenario,a 2 stroke wins.
Yes, what he said. I've owned six outboards. Of the six, one was a Johnson J140 (re-badged Suzuki) four stroke. I'll take a two stroke any day. Hp is hp right? The difference is in the hp/tq curves. Check out this video and draw your own conclusions.
https://www.youtube.com/watch?v=Rfm64xkRU3o
Originally Posted By: outoforder
My father and I have been debating which engine gives the most power for pulling up a skier. He says 4 stroke has better low end torque while 2 stroke has higher top end. I tell him he has it reversed. Thoughts?
In outboards he certainly does.
IME here the newer 4 strokes are not nearly as strong out of the hole, especially with a skier.
My old merc 115 on a 17 foot Cobia Cutlass could easily pull up 4 skiers at once swinging the right prop.
My father and I have been debating which engine gives the most power for pulling up a skier. He says 4 stroke has better low end torque while 2 stroke has higher top end. I tell him he has it reversed. Thoughts?
In outboards he certainly does.
IME here the newer 4 strokes are not nearly as strong out of the hole, especially with a skier.
My old merc 115 on a 17 foot Cobia Cutlass could easily pull up 4 skiers at once swinging the right prop.
I'd agree that on outboards the 2 stroke has a better hole shot than a four stroke.
That being said, I don't waterski and I don't drag race my boat. I want a dependable fishing machine that is light on gas, and for that, I'll take the four stroke every day of the week.
That being said, I don't waterski and I don't drag race my boat. I want a dependable fishing machine that is light on gas, and for that, I'll take the four stroke every day of the week.
Originally Posted By: MNgopher
I'd agree that on outboards the 2 stroke has a better hole shot than a four stroke.
That being said, I don't waterski and I don't drag race my boat. I want a dependable fishing machine that is light on gas, and for that, I'll take the four stroke every day of the week.
Absolutely agreed. While I do not even own a fishing boat, the modern 4 stroker is a fantastic motor in an outboard. Some go a long time between maintenance as well, with simple oil changes very infrequently...
I'd agree that on outboards the 2 stroke has a better hole shot than a four stroke.
That being said, I don't waterski and I don't drag race my boat. I want a dependable fishing machine that is light on gas, and for that, I'll take the four stroke every day of the week.
Absolutely agreed. While I do not even own a fishing boat, the modern 4 stroker is a fantastic motor in an outboard. Some go a long time between maintenance as well, with simple oil changes very infrequently...
I'm surprised no one mentioned the three biggest deciding factors that would generally result in an increase in torque, which would thus mean greater holeshot:
Engine weight
Engine stroke
Overall engine displacement
Lighter weight is always an advantage, two strokes are generally lighter weight then 4 strokes.
Longer stroke generally = more torque. Torque is what you need to get a skiier up
"There's no replacement for displacement". You got more cubes, you generally will have the torque too. I've seen similar HP outboards vary by 10 cu/in or more!
Take for instance the Mercury Grand Marquis I drive. The outgoing Ford 5.0l that the 4.6l modular motor replaced had around 15 less hp then the 4.6 if I remember correctly. However, the 5.0 had an advantage of having a good amount more in torque then the 4.6. Horsepower in engines will not always tell you your torque, or twisting motion. If you want to get a skiier up, you need that twisting motion.
But in the real world, if all I cared about was getting skiiers up and I wanted to do it economically, I would just get the best deal on a 4 stroke and just prop it for the best hole shot (with less speed resulting, but that wouldnt matter in this situation).
I mean, if we are talking power to weight, can anything beat the stump pulling power of a Mercury inline 6 two stroke? Probably not
But can anything drink fuel faster then a tower of power? Probably not.
Engine weight
Engine stroke
Overall engine displacement
Lighter weight is always an advantage, two strokes are generally lighter weight then 4 strokes.
Longer stroke generally = more torque. Torque is what you need to get a skiier up
"There's no replacement for displacement". You got more cubes, you generally will have the torque too. I've seen similar HP outboards vary by 10 cu/in or more!
Take for instance the Mercury Grand Marquis I drive. The outgoing Ford 5.0l that the 4.6l modular motor replaced had around 15 less hp then the 4.6 if I remember correctly. However, the 5.0 had an advantage of having a good amount more in torque then the 4.6. Horsepower in engines will not always tell you your torque, or twisting motion. If you want to get a skiier up, you need that twisting motion.
But in the real world, if all I cared about was getting skiiers up and I wanted to do it economically, I would just get the best deal on a 4 stroke and just prop it for the best hole shot (with less speed resulting, but that wouldnt matter in this situation).
I mean, if we are talking power to weight, can anything beat the stump pulling power of a Mercury inline 6 two stroke? Probably not
But can anything drink fuel faster then a tower of power? Probably not.
Originally Posted By: aquariuscsm
4 strokes have more upper band power. That's what makes them so much fun. Ride a 2 stroke and 4 stroke dirt bike (of same cc) side by side and you'll see what I mean.
Not sure where you got your info but the truth is the exact opposite of what you wrote...... As in any situation, the state of tuning is the single biggest determinant, but for equal displacement, a two-stroke is both torquier and more powerful than a cammer. A four-stroke may have more low-end, though that is often an illusion of sorts, largely the by-product of its generally more linear powerband/torque curve.
Modern DI two-strokes (think E-TEC), especially if they have a variable exhaust port (common known as powervalve) have tackled virtually all of the two-stroke's traditional shortfalls (excessive fuel consumption and pollution, as well as peaky power delivery). FWIW, the E-TEC is the only outboard engine ever to win the EPA's Environmental Excellence Award.....
4 strokes have more upper band power. That's what makes them so much fun. Ride a 2 stroke and 4 stroke dirt bike (of same cc) side by side and you'll see what I mean.
Not sure where you got your info but the truth is the exact opposite of what you wrote...... As in any situation, the state of tuning is the single biggest determinant, but for equal displacement, a two-stroke is both torquier and more powerful than a cammer. A four-stroke may have more low-end, though that is often an illusion of sorts, largely the by-product of its generally more linear powerband/torque curve.
Modern DI two-strokes (think E-TEC), especially if they have a variable exhaust port (common known as powervalve) have tackled virtually all of the two-stroke's traditional shortfalls (excessive fuel consumption and pollution, as well as peaky power delivery). FWIW, the E-TEC is the only outboard engine ever to win the EPA's Environmental Excellence Award.....
As an ex outboard Jr engineer for a major manufacturer, it's clear that 2 strokes have a power advantage. Especially well tuned and well designed 2 strokes.
The advantages 4 stroke engines have is related to development and not basic configuration.
It's not unusual for well prepped 2 stroke engines to have better power to weight by a factor of 2. But, that requires the application of modern methods. Even supercharged 4 strokes have trouble competing by power to weight.
The advantages 4 stroke engines have is related to development and not basic configuration.
It's not unusual for well prepped 2 stroke engines to have better power to weight by a factor of 2. But, that requires the application of modern methods. Even supercharged 4 strokes have trouble competing by power to weight.
Assuming they have the reliability aspect dealt with (a two-stroke will always be inherently "closer to the edge" due to the fact that its piston gets heated on every stroke as opposed to every second one on a cammer) the modern DI two-stroke is superior in every way (more fuel efficient due to reduced internal friction and pumping losses; lighter; more powerful; requires less maintenance - no valves or cam chains to adjust; clean operation - at least equal to a four-stroke, with much lower CO emissions, especially at low (ie. trolling) speeds).... it surprises me that people still opt for four-strokes.... goes to show the power of urban legends/misinformation (eg. v-twins are inherently torquier, or I4's are peaky..... and the list goes on)
Originally Posted By: Mik
FWIW, the E-TEC is the only outboard engine ever to win the EPA's Environmental Excellence Award.....
And the new ones have 500 hour service intervals! They even color match them to your tastes.
pretty hard not to like them...
FWIW, the E-TEC is the only outboard engine ever to win the EPA's Environmental Excellence Award.....
And the new ones have 500 hour service intervals! They even color match them to your tastes.
pretty hard not to like them...
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