OK, what's actually... torque?

ndee

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Jul 18, 2000
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For "WHAT" is torque? Doesn't torque also kinda depend on the tires? And is that true: torque = fast acceleration?

Thanks

ndee, who has NO idea about cars
 

WinkOsmosis

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Torque is the turning force of the engine. Pound feet is the number of pounds that would be exerted by a 1 foot lever attached to the crankshaft.
 

ndee

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OK, but that's actually the head-bangs-to-the-back-effect if you floor the car?
 

WinkOsmosis

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Originally posted by: ndee
OK, but that's actually the head-bangs-to-the-back-effect if you floor the car?
That is caused by change in acceleration, which is caused by rear wheel torque, not the engine torque. This is why a higher gear ratio differential means quicker acceleration.
 

ndee

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Jul 18, 2000
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Originally posted by: Jellomancer
Originally posted by: ndee
OK, but that's actually the head-bangs-to-the-back-effect if you floor the car?
That is caused by change in acceleration, which is caused by rear wheel torque, not the engine torque. This is why a higher gear ratio differential means quicker acceleration.

OK, that means such a truck with 500lb torque could tow........ damn, I don't get it..... but uhm, engine-torque and rear-wheel is in direct relation, right? Cuz then I would get it.

ndee, me is stoopid
 

ElFenix

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torque is rotational force. HP is merely a number calculated by torque*RPM/5250. torque is an instantaneous number, HP is work/time. what makes burnouts is torque, what pushes you into your seat is torque, snapping your head back when the light turns green is torque.
 

ndee

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Jul 18, 2000
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Originally posted by: ElFenix
torque is rotational force. HP is merely a number calculated by torque*RPM/5250. torque is an instantaneous number, HP is work/time. what makes burnouts is torque, what pushes you into your seat is torque, snapping your head back when the light turns green is torque.


Thaaaaaaanks, that was the explanation I was looking for :)
 

WinkOsmosis

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Sep 18, 2002
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Originally posted by: ndee
Originally posted by: Jellomancer
Originally posted by: ndee
OK, but that's actually the head-bangs-to-the-back-effect if you floor the car?
That is caused by change in acceleration, which is caused by rear wheel torque, not the engine torque. This is why a higher gear ratio differential means quicker acceleration.

OK, that means such a truck with 500lb torque could tow........ damn, I don't get it..... but uhm, engine-torque and rear-wheel is in direct relation, right? Cuz then I would get it.

ndee, me is stoopid
They are in direct relation, but rear wheel torque depends on the gearing too.
The only reason engines with high torque/low hp are viewed as "stump pulling" is because at 5252 rpm, their torque output is significantly lower than at lower revolutions, resulting in low power.
 

MinorityReport

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Jul 2, 2002
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Torque is Force x Distance

Units is Newton Meters ( do not use useless non metric crap)


Torque applies to any force/distance situation starting from a screwedriver twist to a soace shuttle launch.

For automobiles, TORQUE in layman terms is the measurement of the twisting or rotational force.

An engine crankshat pushes the pistons turning rotational KE into Torque. So a car uses its HORSEPOWER ( 1 HP = 746 Watts)to make Torque.

An engine will run evenly from somewhere around idle speed (about 800 revolutions per minute or rpm) to its "red line" which might be anywhere from 4000rpm for an older engine to 12000rpm for a Formula One engine. The power and torque will vary through this rev range.

Torque increases as revs increase from idle to a certain figure and then falls as the revs increase above this figure. Acceleration is proportional to the amount of force pushing the vehicle forward, so maximum acceleration in a given gear is attained when maximum torque is attained.

Power is force (~torque) multiplied by speed (~revs) so power increases with revs up to and past the point of maximum torque. However, at still higher revs the engine starts to be limited by the amount of air that it can draw in (4 valves per cylinder help) and torque then decreases more rapidly than the revs increase and therefore power also decreases.

Power is force multiplied by speed, and maximum acceleration is attained by having maximum propulsive force at the wheels. Use of a low gear-ratio multiplies the engine torque at the wheel (at the price of having the engine rotate more quickly). Maximum acceleration at a given speed is attained by having the engine operating at maximum power.



For example a CAT bulldozer with a 12 L V8 diesel pumps out 240 HP. A maxima V6 3 liter has 240 HP.
However, this CAT dozer will have 1500 Nm torque where as Maxima will have 100Nm.
Also this Torque from the CAT will be at sub 1000 RPM where as Maxima needs to be gassed to 2500 RPM for max torque.

So maxima will speed away into oblivion comapred to CAT. But when it comes to that twisting force called torque, the bulldozer will blow the car away because its blade needs to push horrendous amounts of heavy dirt and rock ahead of the vehicle, while the car just needs to push itself and a driver through the air.


Tyres do help in torque .. but marginal performance. No matter what you try it will be 2-7% gain max.
If you divide Torque by the radius of wheels, that is the ROAD GRIP ratio.




Question : At what RPM does an electric motor have max Torque ?

 

ndee

Lifer
Jul 18, 2000
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Originally posted by: MinorityReport
Torque is Force x Distance

Units is Newton Meters ( do not use useless non metric crap)


Torque applies to any force/distance situation starting from a screwedriver twist to a soace shuttle launch.

For automobiles, TORQUE in layman terms is the measurement of the twisting or rotational force.

An engine crankshat pushes the pistons turning rotational KE into Torque. So a car uses its HORSEPOWER ( 1 HP = 746 Watts)to make Torque.

There is no exact relatinship between Torque and HP .. in general and depends on engien to engine..fuel to fuel.

For example a CAT bulldozer with a 12 L V8 diesel pumps out 240 HP. A maxima V6 3 liter has 240 HP.
However, this CAT dozer will have 1500 Nm torque where as Maxima will have 100Nm.
Also this Torque from the CAT will be at sub 1000 RPM where as Maxima needs to be gassed to 2500 RPM for max torque.

So maxima will speed away into oblivion comapred to CAT. But when it comes to that twisting force called torque, the bulldozer will blow the car away because its blade needs to push horrendous amounts of heavy dirt and rock ahead of the vehicle, while the car just needs to push itself and a driver through the air.


Question : At what RPM does an electric motor have max Torque ?

OK, nice exapmle, thx :)

ndee, little less stoopid
 

ElFenix

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Originally posted by: MinorityReport


Question : At what RPM does an electric motor have max Torque ?

as close to 0 as you can get it, i think. do they even have a peak?