Torque Talk

[v10motorhead]

Most of us would be knowing a current F1 engine would be producing some 800 - 920bhp depending on whether its a Cosworth or a BMW... Does anyone have any data/figures as to how much Torque (Nm) a current engine would produce? Does anyone have any kW - Nm - Revs graphs? Just curious

[Reca]

Assume peak power is 900 hp @ 19000 rpm meaning 671 kW @ 1990 rad/s => torque at peak power is then 337 Nm. Torque at peak power is obviously a bit lower that max torque => peak torque is probably about 350 Nm (258 lb ft) or little more and would probably occur somewhere around 15500 rpm.

[v10motorhead]

Ah yes... Power = Torque x Angular Velocity!

My formulae need brushing up! Out of touch with engineering for about 2 yrs now.... Hv to put my head down now....

[NickT]

Just to put the figures into perspective, most modern performance diesel engines running in you Ford Focus or VW Golf or Peugeot 307 are producing some where in the region of 220 to 260 Nm ( 162.24 to 191.74 lb/ft)

I was reading the following link http://www.revsearch.com/dynamometer/comments.html which gave the following equation for deriving hp from any given torque and rpm

hp = [torque (lb-ft) * rpm] / 5252

Therefore: hp * 5252 = torque (lb-ft) * rpm

Therefore: torque (lb-ft) = (hp * 5252) / rpm

Using the figures above = (900 * 5252) / 19000
= 4726800 / 19000
= 248.78 lb ft

Assuming peak torque is produced around 17500 rpm with say 870 hp then peak torque would be
= (870* 5252) / 17500
= 4569240 / 17500
= 261.10 lb ft

Which is pretty close Reca's peak @ 15500 This would be faily indicative of a modern F1 engine. One of the defining charactoristics of a modern F1 engine is its broad power band and associated flat torque curve across the upper rpm range

Excellent stuff getting the old grey matter pumping again

Thanks guys

[Reca]

I doubt very much that an engine with 900 hp @ 19000 rpm could have 870 hp @ 17500. I would be very surprised if it was more than 835-840 hp @ 17500 actually because the rule of thumb is an average of about 40 hp per 1000 rpm past peak torque (higher @ peak torque, lower @ peak power, obviously). According to this first order approximation and assuming peak torque = 350 Nm the peak torque rpm should be about 15500. Considering the level of approximation I agree that it could be a bit higher, probably between 15500 and 16000, difficulty > 16000, surely not at 17500.

On the contrary, 260 Nm is very low for a performance diesel of about 2000 cc, 320-330 is the norm nowadays. But the fact that it’s just a bit lower that peak torque of a F1 engine is obviously meaningless because it’s torque at the wheels what counts and that’s torque times the gear ratio. That’s why to compare the power gives a better indication of the difference between two engines.

[CTsoldier]

350Nm,it looks like the F1 car's torque is not so high about its bhp.Some big and sport car have 600Nm.I want to know if the torque is higher the car can carry a heavier load ?For example can the F1 car pull a truck?

[ReubenG]

For a tyre driven vehicle, the maximum towing force a vehicle can achieve is equal to the weight of the vehicle times the tyre/road frictional coefficient - I'm deliberately ignoring aerodynamic downforce because this is only significant at higher speeds. The available towing force is related to the the engine torque, gear ratios and tyre radius.

[Mikey]

You should not be surprised that the torque is rather low for such an engine. Firstly in simple terms torque=force x distance;

In order to minimse the distance that the piston must travel and consequently enable it to rev to a higher limit, the stroke in such engines is very short, thus the torque is low - however, Power = force x revs and the revs are extremely high, so F1 engines generate loads of power, but not much torque.

As for the example of could an F1 car tow a heavy load - an earlier correspondant highlighted that it would be difficult to maintain traction due to the low weight of the F1 vehicle.

[Reca]

1. Torque is force x distance, where distance is the segment between point of application of the force and the pivot, and x is the vector product, it gives a vector from two vectors. Force is a vector, distance is a vector, torque is a vector. Distance here IS NOT the travelled distance. In SI units the unit of the modulus of torque is Newtonmeter.

2. Force * travelled distance, where * is the scalar product (it gives a scalar from two vectors), is work. Force is a vector, distance is a vector, work is a scalar.

3. Torque IS NOT work. For angular motion the work (scalar) is torque (vector) * angular rotation (vector). In SI unit the unit of work is N * m and it’s called Joule, J. Joule IS NOT Nm. Write it 1000 times : JOULE IS NOT NEWTONMETER. To have J from Nm you have to multiply Nm for the rotation, in SI the unit of rotation is the radian, a complete rotation is 2 * pi radians. If you are using a screwdriver you can apply hundreds or even thousands of Nm of torque but if the rusty screw doesn’t rotate you aren’t doing work.

4. Power (scalar) is work (scalar) divided by the time (scalar), so it’s torque * angular rotation divided by the time required for the rotation, hence, if we consider the angular rotation as a complete revolution you have power = torque * revolutions per second = torque * rotational speed.

5. Long stroke doesn’t equate to more torque because the piston has to travel more. Given the total displacement of the engine the maximum torque isn’t dependant by the bore/stroke ratio (if we put aside some secondary effects that have nothing to do with stroke length), the only theoretical difference between a short stroke and a long stroke engine of equal total displacement, will be the rpm of peak torque, with an higher bore/stroke ratio simply the engine will have the same peak torque at higher rpm (hence more power, that’s why race engine rev high). The maximum torque you can have from a NA engine is in the order of 120 Nm per liter, very difficultly more, so a F1 engine, being a 3 liter is in the ballpark of 360 Nm at peak torque. Any very standard and “calm” production engine of more than 4 liter can easily have an higher peak torque at the crankshaft than the best F1 engine. Still what counts is the torque at the wheels, and that’s torque at the crank times the gear ratio meaning power divided by the wheels rotational speed. And to find a production engines with more power than a F1 engine isn’t that easy.

[schumiGO]

I am sure that Toyota has 120Kg*M (1200 n*m)this year. I asked some man who realy khow this. But for formula 1 torqe is not a great aim!! HP Is AIM for all engine)

[riff_raff]

Saw the in-car video and telemetry from a Williams-BMW during a race this year. They were upshifting at 18,400 rpm and downshifting at about 14,500 rpm. Also, the car left the pits, from a standstill, at about 9000 rpm.

A useable power band of about 4000 rpm. Hmmm....my Chevy truck only has a useable power band of about 2500 rpm.

[CTsoldier]

Ok,THX.I understand the knowlage that you talk about torqe.

[Reca]

I am sure that Toyota has 120Kg*M (1200 n*m)this year. I asked some man who realy khow this.

If Toyota had 1200 Nm of peak torque at the crank it would have WAY more than the 960 hp the same man claims to be the peak power. For example if the peak torque was at just 10000 rpm it would mean 1700 hp... and it wouldn't even be the peak of power. Does it sound plausible to you ?

[Guest]

One of the things which needs to be factored into these equations is the gear ratio. If you have a 500Hp V8 such as a TVR it would produce approximately 592Nm @ a theoretical redline of 6000Rpm (i know they can rev faster but this is just for comparison)

An F1 car with 920Hp will provide approximately 345Nm @ 19000 Rpm.

If both cars were geared to redline in top gear at 200Mph the F1 gear ratio would be 3.167 times larger than the road car.

So with the F1 car having a 42% defecit in engine output torque it would achieve a 184.5% increase in torque at the rear wheels.

This of course does not take into account gearbox and diff efficiencies.

Talking with little engine experience it would seem correct to me that the small components and highly refined F1 engines would produce lower torque figures than diesels or big V6 and V8 engines.

Larger engine torques could become a killer in F1 engines because weight critical components such as crankshafts would have to maintain integrity at increased torque causing increased weight. I suppose F1 designers have concentrated their efforts on the advantages of speed as opposed to torque.

[Alic01]

Sorry that last post was me, forgot to sign in!!