How do you increase Torque?

[Slicks]

All else being equal, the second car would have the same acceleration at twice the road speed. If you measured the acceleration at the same road speed the second car would have twice the acceleration. So at any road speed the second car will be faster.

There is no second car, its the same car.. read.

[Slicks]

Wrong, You obviously are mislead or not very intelligent because you are blatantly disregarding the fact that the kinetic energy required is equal to half the mass of the object times the square of the objects velocity. that means that if you double the speed, you need to add 4 times the energy. Power is energy per unit time so to continue a given rate of acceleration at twice the speed you would need to make 4 times the power. Since you only doubled power you would cut the acceleration in half even though your torque remained constant. I hope everyone else here can see this obvious flaw.

Acceleration follows the power curve exactly.


wrong the second car would accelerate at half the rate of the first one at twice the speed. Otherwise you are correct with twice the power it would accelerate faster at any given speed than the first car.

LMFAO!
This is something you can actually try yourself. Get in a a non-turbo car (preferably a V6 or V8 truck, for the powerband) and put it in 1st gear. Mash on the gas when your at the RPM where the engine makes its peak torque. Feel that kick in the pants? Now bring the RPMs up there the engine makes it peak power, and mash the gas. You will notice that the car jumps much harder at its peak torque, because TORQUE moves the car. I said preferably a truck because of its torque curve, generally they make a lot of low end torque, and not much high end torque, the results will be more noticable. Yoru car literally follows the torque curve when it accelerates. My car pulls no harder at 3000RPMs than it does at 5000RPMs, because its making the same amount of TORQUE at those RPMS, you dont feel hp.

[henk4]

Yes indeed I can:

The only reliable graphs I could find compare '97 passats 1.8T against 1.9TDI and I can tell you that the TDI would pull harder in through the gears because it makes 10-15hp more up to 4000rpm. This means that it will pull noticably harder for 2000-2500rpm then change gears at 4500rpm. The petrol engine is behind until 4000rpm where it starts making more power.

That is no proof, as the diesel will also have notably more torque in that rev range.

[Alastor]

There is no second car, its the same car.. read.

That doesn't change anything.

If you have two cars (yes, separate cars):

• Car A - 228 Hp, 300 lb-ft, 4000 RPM
• Car B - 114 Hp, 300, lb-ft, 2000 RPM

Both cars are otherwise identical and have an infinitely variable transmission so that the engine operates at only the engine speed specified above.

Which car can go from 0-60 MPH faster?

[henk4]

That doesn't change anything.

If you have two cars (yes, separate cars):

• Car A - 228 Hp, 300 lb-ft, 4000 RPM
• Car B - 114 Hp, 300, lb-ft, 2000 RPM

Both cars are otherwise identical and have an infinitely variable transmission so that the engine operates at only the engine speed specified above.

Which car can go from 0-60 MPH faster?

maybe you should also stated that the weight is the same

[Alastor]

maybe you should also stated that the weight is the same

Note the comment:

Both cars are otherwise identical

[Slicks]

That doesn't change anything.

If you have two cars (yes, separate cars):

• Car A - 228 Hp, 300 lb-ft, 4000 RPM
• Car B - 114 Hp, 300, lb-ft, 2000 RPM

Both cars are otherwise identical and have an infinitely variable transmission so that the engine operates at only the engine speed specified above.

Which car can go from 0-60 MPH faster?

Because of GEARING, the car with higher RPMs will be making more TORQUE to the wheels.
Take the SAME car in the SAME gear, with those specs and it will not be accelerating any HARDER (altough traveling at a different speed) because your acceleration follows the torque curve exactly.

[hightower99]

LMFAO!
This is something you can actually try yourself. Get in a a non-turbo car (preferably a V6 or V8 truck, for the powerband) and put it in 1st gear. Mash on the gas when your at the RPM where the engine makes its peak torque. Feel that kick in the pants? Now bring the RPMs up there the engine makes it peak power, and mash the gas. You will notice that the car jumps much harder at its peak torque, because TORQUE moves the car. I said preferably a truck because of its torque curve, generally they make a lot of low end torque, and not much high end torque, the results will be more noticable. Yoru car literally follows the torque curve when it accelerates. My car pulls no harder at 3000RPMs than it does at 5000RPMs, because its making the same amount of TORQUE at those RPMS, you dont feel hp.

You obviously have never tried that with objective measurement (because your ass is biased) This isn't even close to true in the real world. Go ahead try it with some sort of measuring instrument and tell me the results.

You are incorrectly assuming that the energy needed for a given rate of acceleration is independant of velocity. You are totally wrong there, the faster you go the more energy you need to put into the car just to maintain a constant rate of acceleration.

Next you cannot "feel" torque, what you feel is inertial effects from the acceleration of the car which is caused by power. Torque is instantaneous it doesn't have a time or motion componant. When you add the necessary time componant guess what you get... Yup power!

Tell you what, if torque is what moves things then you should be able to tell me the theoretical minimum torque needed to accelerate a car that weighs 1000kg from 0m/s to 20m/s in 3 seconds. If you can give me an answer I will bow out. Since power is what decides acceleration i CAN tell you exactly what the minimum power needed will be to do this.

That is no proof, as the diesel will also have notably more torque in that rev range.

look closer I said the petrol kills it later in the rev range where it makes less torque than the diesel but manages to out accelerate it.

Because of GEARING, the car with higher RPMs will be making more TORQUE to the wheels.
Take the SAME car in the SAME gear, with those specs and it will not be accelerating any HARDER (altough traveling at a different speed) because your acceleration follows the torque curve exactly.

You are an idiot! get it through your thick skull that acceleration is highly velocity dependant.

it takes alot more energy to accelerate from 100-120 km/h then it does to accelerate from 0-50km/h... please understand this.

I can explain with math and real world examples why and how power does everything. You are using highly subjective and limited experiances to argue your point.

Please somebody who believes that torque is what accelerates you please post an acceleration graph on top of a torque curve graph that matches perfectly.

BTW: I know that was an impossible request...

Also note that torque is changed by gear ratios. Power is not.
This alone should convince most people.

[henk4]

look closer I said the petrol kills it later in the rev range where it makes less torque than the diesel but manages to out accelerate it.

yes, but in that situation the diesel will already have shifted a gear up....(to find more torque again).

[hightower99]

yes, but in that situation the diesel will already have shifted a gear up....(to find more torque again).

Which would support my arguement because then the diesel will be making alot more torque then the petrol but the petrol will still be accelerating harder.

[henk4]

Which would support my arguement because then the diesel will be making alot more torque then the petrol but the petrol will still be accelerating harder.

no, the diesel will be accelerating harder.

[Alastor]

Because of GEARING, the car with higher RPMs will be making more TORQUE to the wheels.

Both cars are given an “infinite” number of gears, so there really isn’t a gearing advantage for either one.

Take the SAME car in the SAME gear, with those specs and it will not be accelerating any HARDER (altough traveling at a different speed) because your acceleration follows the torque curve exactly.

So are you saying it is fair to measure acceleration of two cars at different road speeds?

Is a 4-speed transmission better than a 6-speed transmission, no. Why use more gears if it doesn’t change peak acceleration in a specific gear? Because more gears allows the engine to operate near the peak power output across a larger range or road speeds.

You are thinking in terms of torque and engine speed, which is fine for just an engine. But when you put the engine in a car with a transmission, and you want the best performance (maximizing acceleration) you have to think in terms of wheel torque and wheel speed.

[hightower99]

no, the diesel will be accelerating harder.

What makes you think that? it would be in a higher gear and it would have dropped down in the rev range to where it makes roughly 60hp...

The petrol would be in a lower gear and would be producing 130hp. Both would be traveling at roughly the same speed (if you do the math the petrol is in front by a few km/h).

The petrol is accelerating harder period.

The diesel is making more torque period.

The theory that torque determines your rate of acceleration is therefore proven wrong.

Don't believe me?
get acceleration graphs that prove me wrong.

[drakkie]

The diesel is making more torque period.

Sigh.... You proved yourself wrong your own post ! That must be a first Let me scan these kind of graphs for you after work. I'll also include a lengthy technical explanation.

Take it, you are wrong. My classmates and me had a good gniffle about your posts !

I will also give my brain a quick wake-up call and tell you the amount of Nm that is needed for the 1000 kg car...

[hightower99]

Sigh.... You proved yourself wrong your own post ! That must be a first Let me scan these kind of graphs for you after work. I'll also include a lengthy technical explanation.

Take it, you are wrong. My classmates and me had a good gniffle about your posts !

I will also give my brain a quick wake-up call and tell you the amount of Nm that is needed for the 1000 kg car...

I wait with great anticipation...

by the way I do have the dyno charts that show the diesel making more torque than the petrol in the situation described.