But I was just in one and it hung at peak torque at full throttle.
All the theories won't change that.
All the theories won't change that.
Low end torque is low end horsepower
- Thread starter Stelth
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And I test drove a new Altima and it went straight to 6 grand and stayed there at full throttle.
My Murano V-6 did the exact same thing.
My Murano V-6 did the exact same thing.
A Formula 1 engine produces about as much torque as a typical V6 engine currently used in North American cars. Now, to get the most horse power, would you like to row your gears to keep the engine in its 16,000 to 20,000 RPM power band all the time? I think this answers the question.
For a daily driver, you want a good amount of low-end torque. For a race track car? Does it really matter as long as it has good horse power?
For a daily driver, you want a good amount of low-end torque. For a race track car? Does it really matter as long as it has good horse power?
Originally Posted By: mechtech2
But I was just in one and it hung at peak torque at full throttle.
All the theories won't change that.
Year, make and model?
I have posted vids of numerous CVT models and not a single one has maintained peak torque RPM at WOT, all have went straight to peak HP. I've never driven one that went to torque peak at WOT either.
But I was just in one and it hung at peak torque at full throttle.
All the theories won't change that.
Year, make and model?
I have posted vids of numerous CVT models and not a single one has maintained peak torque RPM at WOT, all have went straight to peak HP. I've never driven one that went to torque peak at WOT either.
OK, I have a question, or rather a belief, to suggest.
We've agreed (I think) that a 350 hp Cummins that makes 1400 ft. lbs. of torque at 1200 rpm is more practical for moving heavy objects that are at rest than a Formula 1 engine that makes 204 ft. lbs. at 19000 rpm.
However, the F1 engine in question is also making 740 hp at that rpm level, and the Cummins is making about 320 hp at its torque peak. Therefore, if you gear the F1 engine so that you're getting that 19000 rpm at the flywheel, but 1200 rpm at the output shaft, you will now have 3238 ft. lbs. of torque available (assuming no power losses in the transmission, which is admittedly inaccurate), and will be able to pull much more weight than with the Cummins.
N'est-ce pas?
We've agreed (I think) that a 350 hp Cummins that makes 1400 ft. lbs. of torque at 1200 rpm is more practical for moving heavy objects that are at rest than a Formula 1 engine that makes 204 ft. lbs. at 19000 rpm.
However, the F1 engine in question is also making 740 hp at that rpm level, and the Cummins is making about 320 hp at its torque peak. Therefore, if you gear the F1 engine so that you're getting that 19000 rpm at the flywheel, but 1200 rpm at the output shaft, you will now have 3238 ft. lbs. of torque available (assuming no power losses in the transmission, which is admittedly inaccurate), and will be able to pull much more weight than with the Cummins.
N'est-ce pas?
Originally Posted By: Archimedes
Give me a lever long enough and a fulcrum on which to place it, and I shall move the world
Yes, you are right...the F1 engine can be geared down to provide more than enough tractive effort, and in fact provide twice the torque of the cummins (due to having twice the power available) at a given output speed of the chosen reduction box.
The converse is that no matter how much torque the Cummins puts out for it's 350hp, it can never be geared to punch the F1 car through the air at 200MPH
Give me a lever long enough and a fulcrum on which to place it, and I shall move the world
Yes, you are right...the F1 engine can be geared down to provide more than enough tractive effort, and in fact provide twice the torque of the cummins (due to having twice the power available) at a given output speed of the chosen reduction box.
The converse is that no matter how much torque the Cummins puts out for it's 350hp, it can never be geared to punch the F1 car through the air at 200MPH
Originally Posted By: Shannow
Originally Posted By: Archimedes
Give me a lever long enough and a fulcrum on which to place it, and I shall move the world
Yes, you are right...the F1 engine can be geared down to provide more than enough tractive effort, and in fact provide twice the torque of the cummins (due to having twice the power available) at a given output speed of the chosen reduction box.
The converse is that no matter how much torque the Cummins puts out for it's 350hp, it can never be geared to punch the F1 car through the air at 200MPH
Shannow, in this thread and others, I've appreciated your reasoned and level-headed responses.
Originally Posted By: Archimedes
Give me a lever long enough and a fulcrum on which to place it, and I shall move the world
Yes, you are right...the F1 engine can be geared down to provide more than enough tractive effort, and in fact provide twice the torque of the cummins (due to having twice the power available) at a given output speed of the chosen reduction box.
The converse is that no matter how much torque the Cummins puts out for it's 350hp, it can never be geared to punch the F1 car through the air at 200MPH
Shannow, in this thread and others, I've appreciated your reasoned and level-headed responses.
HD Truck transmissions with 25:1 first gears exist. Its a specialized application though. Another way to get there is an auxiliary reduction transmission.
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Its possible, highway tractors run in the range of 3.7:1 rear gears, rear ends of up to 7 exist without even being deep reduction models, so you get half of it there. An auxiliary can double that there so you are up to 4x. A super deep transmission as per above gives you double the first gear, you are up to 8x more gearing than a truck. That 200 ft lbs the F1 is making is now like 1600 ft lbs. Thats number is typical for a modern 13L diesel.
Originally Posted By: Ben99GT
Originally Posted By: mechtech2
But I was just in one and it hung at peak torque at full throttle.
All the theories won't change that.
Year, make and model?
I have posted vids of numerous CVT models and not a single one has maintained peak torque RPM at WOT, all have went straight to peak HP. I've never driven one that went to torque peak at WOT either.
Got real quiet after that one.
Originally Posted By: mechtech2
But I was just in one and it hung at peak torque at full throttle.
All the theories won't change that.
Year, make and model?
I have posted vids of numerous CVT models and not a single one has maintained peak torque RPM at WOT, all have went straight to peak HP. I've never driven one that went to torque peak at WOT either.
Got real quiet after that one.
Originally Posted By: Ben99GT
For example:
Subaru 2.5 - 170 HP @ 5600 rpm, 170 LB-FT @ 4000 rpm
I watched all three videos and what I don't understand is after the rpms get up around 5 or 6 thousand they go up very, very slowly. Are you just cruising at that rpm and not have the pedal matted? My Ranger pickup 4 banger the rpms go up very fast at the upper rpm levels. If your video is with the pedal to the metal, then you need to shift earlier, for some reason power seems to be dying off at the upper rpms.
For example:
Subaru 2.5 - 170 HP @ 5600 rpm, 170 LB-FT @ 4000 rpm
I watched all three videos and what I don't understand is after the rpms get up around 5 or 6 thousand they go up very, very slowly. Are you just cruising at that rpm and not have the pedal matted? My Ranger pickup 4 banger the rpms go up very fast at the upper rpm levels. If your video is with the pedal to the metal, then you need to shift earlier, for some reason power seems to be dying off at the upper rpms.
Back in the day, I'm talking 1920's and 30's when this started all cars were naturally manual and people like today hated to shift. So it was the sign of a quality high end car if it could pull away in top gear at 5mph. This was part of a road test in the day like 0-60 is today.
This is why you get massive 7L Bentley's and Packard's with all kinds of torque because you could drop them in top gear and never have to shift ever since 40-50 mph was about as fast as you could go.
In Europe it was a sign of luxury because you were taxed on displacement, so only the wealthy could afford large displacement cars, and as a result could "waft" around in proper luxury.
This carried forward today is why the Rolls Royce 6.75L V8 is so fantastic, that engine puts out all kinds of torque down low. Or the Mercedes twin turbo V12 which pulls like a freight train from right off idle.
This is why you get massive 7L Bentley's and Packard's with all kinds of torque because you could drop them in top gear and never have to shift ever since 40-50 mph was about as fast as you could go.
In Europe it was a sign of luxury because you were taxed on displacement, so only the wealthy could afford large displacement cars, and as a result could "waft" around in proper luxury.
This carried forward today is why the Rolls Royce 6.75L V8 is so fantastic, that engine puts out all kinds of torque down low. Or the Mercedes twin turbo V12 which pulls like a freight train from right off idle.
Originally Posted By: TallPaul
Originally Posted By: Ben99GT
For example:
Subaru 2.5 - 170 HP @ 5600 rpm, 170 LB-FT @ 4000 rpm
I watched all three videos and what I don't understand is after the rpms get up around 5 or 6 thousand they go up very, very slowly. Are you just cruising at that rpm and not have the pedal matted? My Ranger pickup 4 banger the rpms go up very fast at the upper rpm levels. If your video is with the pedal to the metal, then you need to shift earlier, for some reason power seems to be dying off at the upper rpms.
It's because it's a CVT. Once it hits the desired engine speed, the gear ratio varies with acceleration instead of the engine speed.
Originally Posted By: Ben99GT
For example:
Subaru 2.5 - 170 HP @ 5600 rpm, 170 LB-FT @ 4000 rpm
I watched all three videos and what I don't understand is after the rpms get up around 5 or 6 thousand they go up very, very slowly. Are you just cruising at that rpm and not have the pedal matted? My Ranger pickup 4 banger the rpms go up very fast at the upper rpm levels. If your video is with the pedal to the metal, then you need to shift earlier, for some reason power seems to be dying off at the upper rpms.
It's because it's a CVT. Once it hits the desired engine speed, the gear ratio varies with acceleration instead of the engine speed.
Originally Posted By: rationull
It's because it's a CVT. Once it hits the desired engine speed, the gear ratio varies with acceleration instead of the engine speed.
Ah thank you. I obviously know absolutely nothing about these new fangled contraptions. It would be pretty weird to drive that thing. Take some getting used to.
It's because it's a CVT. Once it hits the desired engine speed, the gear ratio varies with acceleration instead of the engine speed.
Ah thank you. I obviously know absolutely nothing about these new fangled contraptions. It would be pretty weird to drive that thing. Take some getting used to.
and NO one looked up what James Watt says about horsepower?
Originally Posted By: Stelth
Not sure why this never really clicked in my mind, probably because of all the weird theories and superstitions I've heard over the years about torque and horsepower, but the recent thread about flat torque curves did it.
I've heard so many people say so many different things: "OK, when you're starting from a dead stop, that's when you need torque." Or, "For towing, you really need an engine with lots of torque." IOW, for some things you need horsepower, for other things you need torque. Well, please pardon me if I say, "Horsefeathers."
When we talk about engines, torque IS horsepower, because of the formula torque x rpm /5252 = hp. Engine torque is calculated at a particular rpm which means it's not static torque.
I believe the current 6.7L Dodge/Cummins diesel makes 350 horsepower at 3013 rpm. It makes 800 ft. lbs. of torque at 1600 rpm. That's a lot of low end torque, but it's also 243 horsepower. 243 horsepower at 1600 is also a LOT of low end horsepower.
I remember years ago seeing a rating plate on a Cummins diesel in an over-the-road tractor. It said the engine made 350 hp at 2000 rpm and 1400 ft. lbs. at 1200 rpm. That's about 320 hp at 1200 rpm.
So whether you say you want low-end torque, or low-end horsepower, or low-end grunt or whatever, it's all the same thing.
HP is torque x rpm
More torque = more hp.
or
More rpm = more hp.
which is why small japanese engines are high revving engines. They are low in torque, yet have good horsepower.
Simple.
Not sure why this never really clicked in my mind, probably because of all the weird theories and superstitions I've heard over the years about torque and horsepower, but the recent thread about flat torque curves did it.
I've heard so many people say so many different things: "OK, when you're starting from a dead stop, that's when you need torque." Or, "For towing, you really need an engine with lots of torque." IOW, for some things you need horsepower, for other things you need torque. Well, please pardon me if I say, "Horsefeathers."
When we talk about engines, torque IS horsepower, because of the formula torque x rpm /5252 = hp. Engine torque is calculated at a particular rpm which means it's not static torque.
I believe the current 6.7L Dodge/Cummins diesel makes 350 horsepower at 3013 rpm. It makes 800 ft. lbs. of torque at 1600 rpm. That's a lot of low end torque, but it's also 243 horsepower. 243 horsepower at 1600 is also a LOT of low end horsepower.
I remember years ago seeing a rating plate on a Cummins diesel in an over-the-road tractor. It said the engine made 350 hp at 2000 rpm and 1400 ft. lbs. at 1200 rpm. That's about 320 hp at 1200 rpm.
So whether you say you want low-end torque, or low-end horsepower, or low-end grunt or whatever, it's all the same thing.
HP is torque x rpm
More torque = more hp.
or
More rpm = more hp.
which is why small japanese engines are high revving engines. They are low in torque, yet have good horsepower.
Simple.
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