View Poll Results: HP -> Acceleration... not Torque!
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HP -> Acceleration... not Torque!
Registered User
Joined: Jan 2002
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From: Redford, MI
Originally posted by KnightRider
Actually, the slower you are moving the more torque you can have at the wheels because you can use a lower gear. Try gearing a car for max acceleration at 10mph and at 30mph and see what happens.
Actually, the slower you are moving the more torque you can have at the wheels because you can use a lower gear. Try gearing a car for max acceleration at 10mph and at 30mph and see what happens.
[QUOTE][B]
Zoran said that wheel torque is much more related to HP than torque and you said not if gearing is static. Not true, try to tell me how much torque the engine is producing if you are producing say 5000lb-ft at 500 wheel rpms. Whether the gearing is static or not I can tell you the HP at the engine.
Registered User
Joined: Jan 2002
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From: Redford, MI
Originally posted by KnightRider
Even if your gearing is static you still need to know what the gear ratio is to determine torque at the engine from torque at the wheels for a given speed. You know why? Because you need the gear ratio to determine engine rpms from the vehicle speed. So once again you end up with torque and rpm which is what... Horsepower!
Even if your gearing is static you still need to know what the gear ratio is to determine torque at the engine from torque at the wheels for a given speed. You know why? Because you need the gear ratio to determine engine rpms from the vehicle speed. So once again you end up with torque and rpm which is what... Horsepower!
Torque has nothing to do with speed. Torque accelerates the car, period. a=F/m, velocity is not involved. If you want to talk about speed then we can talk about horsepower. But I am talking about acceleration not speed.
Registered User
Joined: Apr 2001
Posts: 854
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From: Houston
[QUOTE]Originally posted by Destiny2002
[B]Here's a problem for you guys to solve:
You need to accelerate a 3000 lb car from 10 to 30 MPH in 2 seconds flat.
Either tell me:
(A) the average torque required from the engine,
or
[B]Here's a problem for you guys to solve:
You need to accelerate a 3000 lb car from 10 to 30 MPH in 2 seconds flat.
Either tell me:
(A) the average torque required from the engine,
or
Registered User
Joined: Jun 2003
Posts: 24
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From: Portland
Originally posted by wc_one
Last time I checked, you can't go lower than 1st gear.
Last time I checked, you can't go lower than 1st gear.
[QUOTE]
[B]
You can?
Registered User
Joined: Jan 2002
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From: Redford, MI
Originally posted by KnightRider
Yes torque at the wheels is what moves the car
Yes torque at the wheels is what moves the car
Woohoo we have a winner![QUOTE][B] but even torque at the wheels by itself tells you nothing about how fast a car will do a quarter mile for instance.
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Joined: Apr 2001
Posts: 854
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From: Houston
wc_one:
I think you understand the issues involved here, but your reasoning is flawed because, in a case of a car travelling at certain speed and going for maximum acceleration:
1. You are assuming that gearing is constant while in fact it is variable
2. You are assuming that velocity is variable while in fact it is constant
Fix those two and you'll see for yourself that the maximum acceleration for a car at any given speed happens if the car is at the peak horsepower.
I think you understand the issues involved here, but your reasoning is flawed because, in a case of a car travelling at certain speed and going for maximum acceleration:
1. You are assuming that gearing is constant while in fact it is variable
2. You are assuming that velocity is variable while in fact it is constant
Fix those two and you'll see for yourself that the maximum acceleration for a car at any given speed happens if the car is at the peak horsepower.