Or more torque at lower RPM.... depends entirely on the application I guess.
And as a silly example......
BMW M5 - 500 bhp
Scania R500 - 500 bhp
One pulls much much harder than the other but its no where near as fast!
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bhp question..
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Or more torque at lower RPM.... depends entirely on the application I guess.
And as a silly example......
BMW M5 - 500 bhp
Scania R500 - 500 bhp
One pulls much much harder than the other but its no where near as fast!
Soldato
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If we we're doing it properly we would take the integral of the portion of each cars power curve in the rpm range used during the acceleration. But its so much easier to quote peaks.
its the same car, same engine, same gear but is it more accelerative at 2krpm or 6krpm
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Pushing the car down the road requires a force. When force acts on an object and displaces the object work is done. In the 6k example more work is done per second than the 2k.
Rate of work = power
Hence:
This higher rate of work = higher acceleration
Rate of work = power
Hence:
Spuderoony said:
This higher rate of work = higher acceleration
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becuase its work done that does the uhm.... work. power figures are just ways of measuring that in ways that either 1, make more sense to the guy down the pub. 2, make a better sales pitch.
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...at the instant at which the engine is producing 200lbft, isn't it producing more acceleration than the instant at which it's producing 100lbft???
thats what i thought. 200lbft twist is a stronger twist than 100lbft
Yes but you are getting either 2K strong twists or 6K weaker twists.
1 Strong push per second moves you 2 foot across the floor, 3 weak pushes per second move you 3 foot across the floor. The 3 weaker pushes accelerate you faster and provide more power.
1 Strong push per second moves you 2 foot across the floor, 3 weak pushes per second move you 3 foot across the floor. The 3 weaker pushes accelerate you faster and provide more power.
No, because the rate at which that torque is being applied to the road is 50% less.
Edit: ^^ What Dureth said just with less explanation
its not an impact gun, it turns in one continuous motion
with low torque, high rpm (high bhp) you can make a quick car (imagine a little honda vtec) because the lower gearing.
higher revs allow for lower gear, getting more torque to the road. the honda is quick because the gearing is lower not because its doing 9000 small pushes....
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I suppose in simple terms,
In a minute, the engine will either do 2000 revolutions at 100 ft/lbs or 6000 revolutions at 200ft/lbs.
This will also explain why low down torque is good for towing, no matter how many weak pulls you do, you might not move, while a few big pulls would be better to move the object.
In a minute, the engine will either do 2000 revolutions at 100 ft/lbs or 6000 revolutions at 200ft/lbs.
This will also explain why low down torque is good for towing, no matter how many weak pulls you do, you might not move, while a few big pulls would be better to move the object.
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I still think 200lbft will accelerate you faster than 100lbft.
How about a propellor engine? At 2000RPM it provides 200lbft. At 6000RPM it provides 100lbft and is certainly doing it at three times the rate. But is the plane accelerating any faster?
How about a propellor engine? At 2000RPM it provides 200lbft. At 6000RPM it provides 100lbft and is certainly doing it at three times the rate. But is the plane accelerating any faster?
Yes, actuallyNo.
If this car, due to gearing, had a resultant 300 lb-ft at 6000 RPM, then reducing to 2000 RPM, doubling the input torque, would have the effect of doubling the output torque. But, of course, you'd not be going 20 MPH at 6000 RPM, you'd be going 7 MPH at 2000 RPM.
The rate of acceleration IS faster when producing 200 lb-ft than when producing 100 lb-ft if the gearing is the same. However, the speed at which you will be travelling at 2000 RPM is one third than at 6000 RPM. If you rev to 6000 RPM, apply a gearing to reduce your speed back down to the same as at 2000 RPM, then you triple your resultant torque and you will then accelerate faster at 6000 RPM.
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