F1 engine torque

[williamssam]

Correct me if i'm wrong but i believe current F1 torque figures are believed to be around 260 lb-ft at maybe 16,000 rpm. In a 3000cc road car engine this is a resonable torque figure, but i find it surprising it's not higher for an F1 engine. I know they're tuned for high rpm to provide as much power as possible but surely the fact they can achive high levels of volumetric efficiency, have large valve areas because of the high bore/stroke ratio and have compression ratios of at least 14:1 would allow them to achieve much higher torque figures. Can anyone shed any light on this topic because I can't figure out the physical reasons for the apparent torque figures.

[riff_raff]

williamssam,

260 lb-ft @ 16,000 rpm is 792 hp, or a bmep rate of 214 psi. Very good for a 3.0L N/A engine. F1 engines are tuned for maximum hp, because hp is what determines how fast the car goes around the track, not torque. The 3.0L road car engine you mention, making 260 lb-ft torque @ 5000 rpm, is only producing 247 hp. See the difference?

Torque is defined as an engines ability to do work. Horsepower is defined as how fast that work gets done.

[RH1300S]

williamssam,

260 lb-ft @ 16,000 rpm is 792 hp, or a bmep rate of 214 psi. Very good for a 3.0L N/A engine. F1 engines are tuned for maximum hp, because hp is what determines how fast the car goes around the track, not torque. The 3.0L road car engine you mention, making 260 lb-ft torque @ 5000 rpm, is only producing 247 hp. See the difference?

Torque is defined as an engines ability to do work. Horsepower is defined as how fast that work gets done.

"Torque wins motor races" - discuss

Hopefully we will get some interesting, rational comment on this

BTW - does anyone know if that is the peak torque figure?

[williamssam]

260 lb-ft @ 16,000 rpm is 792 hp, or a bmep rate of 214 psi. Very good for a 3.0L N/A engine. F1 engines are tuned for maximum hp, because hp is what determines how fast the car goes around the track, not torque. The 3.0L road car engine you mention, making 260 lb-ft torque @ 5000 rpm, is only producing 247 hp. See the difference?

But for a 3.0L engine producing 247 hp at 5000 rpm this also equates to a BMEP of 214 psi. I would have thought that a highly tuned engine, regardless of whether it's been tuned for rpm, would be able to produce a higher BMEP figure. This is obviously not the case, but i can't get my head around the fact that the torque figures aren't any higher. Perhaps it's because at engine speeds of 16,000 rpm the FMEP is much higher than at 5000 rpm.

[ReubenG]

I think you were almost there with your last comment about Friction Mean Effective Pressure (FMEP). The Brake Mean Effective Pressure (BMEP) is arrived at by measuring engine outputs at the flywheel (or clutch). The actual MEP in the cylinder is the sum of BMEP & FMEP. Frictional losses increase incredibly quickly with speed - I am not sure whether it is proportional to (speed)^2 or (Speed)^3. Either way, the losses in an F1 at peak rpm are orders of magnitude higher than in road engines at 5500 rpm.

[williamssam]

Thanks ReubenG. That must mean that, although BMEP is the same for any 3 litre engine producing the same amount of torque, an F1 has a higher FMEP and therefore a higher IMEP, i.e the F1 engine produces more potential energy but a lower proportion is turned into useable energy because of the frictional losses.

[DarkSnape]

williamssam,

260 lb-ft @ 16,000 rpm is 792 hp, or a bmep rate of 214 psi. Very good for a 3.0L N/A engine. F1 engines are tuned for maximum hp, because hp is what determines how fast the car goes around the track, not torque. The 3.0L road car engine you mention, making 260 lb-ft torque @ 5000 rpm, is only producing 247 hp. See the difference?

Torque is defined as an engines ability to do work. Horsepower is defined as how fast that work gets done.

sry but P(hp)x 7023,5 = (revs x torque) well for 16.000 revs and 260Nm torque = 592,29 HP maybe that u want to say

[Figlio_del_Diavolo]

Try to think of it in terms of moment arms generated around the centerline of crankshaft. With a shorter stroke the moments are not as high. This is the whole source of mechanical ouput of the engine.

Ferrari Formula 1 Tipo 049 3.0L V10 Crankshaft- Stroke=41.4 mm(~1.63"):

Chevrolet NASCAR 358ci V8 Crankshaft - Stroke=3.480"(~88.392mm):


Based on the two different cranks it should be easy to see why it is difficult to get high torque in engines with relatively small strokes from a moment point-of-view.

[zac510]

sry but P(hp)x 7023,5 = (revs x torque) well for 16.000 revs and 260Nm torque = 592,29 HP maybe that u want to say

I think you will find that revs x torque only works for hp x lb/ft and with kw/nm. It will not with for nm and hp as that is a cross of imperial and metric.

[Reca]

Try to think of it in terms of moment arms generated around the centerline of crankshaft. With a shorter stroke the moments are not as high. This is the whole source of mechanical ouput of the engine.
[...]
Based on the two different cranks it should be easy to see why it is difficult to get high torque in engines with relatively small strokes from a moment point-of-view.

As a start these two engines have a VERY different displacement, you didn’t catch it because you used two different units, but that F1 engine is a 3000 cc (183 ci) while that NASCAR engine is a 5900 cc (358 ci), close to twice the displacement. Since max torque you can generate from an engine, for a given technological level, is roughly linearly proportional to displacement, it’s evident that the latter, even if not particularly sophisticated, will have higher peak torque, it’s twice as big.

If now you look at a given displacement, you’ll find that the amount of torque generated by an engine isn’t directly influenced by the bore/stroke ratio because even if the stroke is shorter, hence the moment arm is shorter, the force (pressure x area) is larger due to the larger bore and the two effects compensate each other.
Then obviously the short stroke engine will have peak torque at higher rpm but will also have an higher rpm red line, so you just have to let it rev higher, but that doesn’t means it lacks torque, it simply has it at higher rpm. Use the suitable gearbox ratios and you’ll find it all.

There’s actually a possible influence of the bore/stroke ratio on the amount of maximum torque at the crank but it’s an indirect one and only exists while arriving to extreme designs like in F1 where the large bore and the high CR have an effect on the combusting chamber shape hence on the BMEP (that is basically a measure of torque per unit displacement). Anyway that’s a secondary issue non related with the pure kinematics of piston and con rods.

Strangely enough, that myth about long stroke=more torque is something I found only few years ago when I started surfing on the web and mainly coming from US people, I wouldn’t exclude that the imperial units you use (making no clear distinction between torque and work, contrarily to SI units where we use Nm and J respectively) could be one of the cause of the misunderstanding.
Another cause could be US people love for big displacement engines and the fact that consequently that myth is repeated every now and then on car magazines round there bragging about US cars. I wouldn’t also exclude a role is played by the general lack of familiarity with manual gearbox hence with the choice of the right gear ratio for the right situation.

I think you will find that revs x torque only works for hp x lb/ft and with kw/nm. It will not with for nm and hp as that is a cross of imperial and metric.

Just to make it more clear :
Power = revs x torque is the physics law.
If you use the SI units, the ones you should really use for physics calculation if you don’t want to make a multi-million $ mistake (ask NASA...), the ones that will make you really understand what you are doing while applying physics law, then you need torque in Nm and revs in rad/s, you’ll have power in Watt.
If you want to use different units, then you’ll need to adopt conversion factors and these have the tendency to lead to a quantity of mistakes.

For example if you use torque in lb-ft and revs in rpm, you have to divide the result of torque x revs by roughly 5252 to have power in hp (1 hp = 745.7 kW, 1 PS = 1 CV = 735.5 kW) and that gives, as riff_raff said, 792 hp for torque = 260 lbft and rpm = 16000.

Converted in SI units, 260 lb-ft * (0.4536 [lb/kg] * 0.3048 [ft/m] * 9.81 [m/s^2] = 352 Nm. That multiplied for 16000 rpm * 2 * pi / 60= 1675 rad/s gives a power = 590 kW = 792 hp.

[Figlio_del_Diavolo]

As a start these two engines have a VERY different displacement, you didn’t catch it because you used two different units, but that F1 engine is a 3000 cc (183 ci) while that NASCAR engine is a 5900 cc (358 ci), close to twice the displacement. Since max torque you can generate from an engine, for a given technological level, is roughly linearly proportional to displacement, it’s evident that the latter, even if not particularly sophisticated, will have higher peak torque, it’s twice as big.

If now you look at a given displacement, you’ll find that the amount of torque generated by an engine isn’t directly influenced by the bore/stroke ratio because even if the stroke is shorter, hence the moment arm is shorter, the force (pressure x area) is larger due to the larger bore and the two effects compensate each other.
Then obviously the short stroke engine will have peak torque at higher rpm but will also have an higher rpm red line, so you just have to let it rev higher, but that doesn’t means it lacks torque, it simply has it at higher rpm. Use the suitable gearbox ratios and you’ll find it all.

There’s actually a possible influence of the bore/stroke ratio on the amount of maximum torque at the crank but it’s an indirect one and only exists while arriving to extreme designs like in F1 where the large bore and the high CR have an effect on the combusting chamber shape hence on the BMEP (that is basically a measure of torque per unit displacement). Anyway that’s a secondary issue non related with the pure kinematics of piston and con rods.

Strangely enough, that myth about long stroke=more torque is something I found only few years ago when I started surfing on the web and mainly coming from US people, I wouldn’t exclude that the imperial units you use (making no clear distinction between torque and work, contrarily to SI units where we use Nm and J respectively) could be one of the cause of the misunderstanding.
Another cause could be US people love for big displacement engines and the fact that consequently that myth is repeated every now and then on car magazines round there bragging about US cars. I wouldn’t also exclude a role is played by the general lack of familiarity with manual gearbox hence with the choice of the right gear ratio for the right situation.

I know all about different systems of measurement. I was trying to use a simple explanation from a purely physical point of view without taking into account a thermodynamic cycle analysis or anything like that because I felt it would be a waste of my time. There is no need for the "haha stupid American" bs that I feel you ran on about trying to act all high and mighty. You speak like manual transmissions are nonexistant in the States. You also seem like you think I have no clue what something like brake mean effective pressure is, when, in fact, the situation is quite the opposite. Don't take an attempt at a simple explanation, which I admit was pretty half-assed, as a sign of ignorance or stupidity. I am not on here to wax lyrical about combustion analysis and so on and so forth to impress people.

[Frenchblock]

""For example if you use torque in lb-ft and revs in rpm, you have to divide the result of torque x revs by roughly 5252 to have power in hp (1 hp = 745.7 kW, 1 PS = 1 CV = 735.5 kW) and that gives, as riff_raff said, 792 hp for torque = 260 lbft and rpm = 16000. ""

It's my first post, but as ingeneer i can't leave someone saying this!


So 1hp = 746kW ? not 746 Watts?

So, as the torque in Lbs per foot? isn't it in Newtons per meter? for mechanics basis?


todays no ones use imperial mesures to design engines, every ingeneer use SI mesure and all use Newtons and not Lbs!

Hope if you are englishman that you know who was Isaac?

and that you'll leave Lbs to calculations of potatoes!
bye

[m3_lover]

The lbs is mostly because the U.S.A since they use the imperial system, like there gauges are all in MPH while in Canada we use the Metric and everything is in KPH, stuff like. I was actually amazed that in Europe you guys use BHP/ton as a measurement while in North America 0-60 is the main measurement pretty astonishing in fact. You crazy european bastards lol

[ginsu]

Strangely enough, that myth about long stroke=more torque is something I found only few years ago when I started surfing on the web and mainly coming from US people, I wouldn’t exclude that the imperial units you use (making no clear distinction between torque and work, contrarily to SI units where we use Nm and J respectively) could be one of the cause of the misunderstanding.

I don't know how this can confuse you. It's simple trigonometry. A longer stroke can only be accomplished by increasing the moment arm (i.e. crank throw). The same pressure on the same piston area on a longer moment arm increases the torque produced by the engine. Remember, the engine outputs torque, not work.

[DarkSnape]

i read that in the firist press conference of Australia . i think it`s interesting to know

Despite all the changes to the technical regulations this year, specifically with engines, it appears as if the Renault still has a marked advantage off the line at the start of a race. Firstly do you agree with that and secondly if so why do you think that is?
Mark Webber: I definitely agree. I think they are phenomenal off the line. There is a combination of a few things which in terms of the torque of the engine which is helping them, where the weight is in the car and also the electronics and how obviously the clutch and that stuff is working. In all that stuff, they have had the best situation and have had so for a few years even with the V10 and there were a lot of good V10s out there at the end, so that makes the torque one a bit less of an argument but I think the V8 enjoys some good torque. Fernando and Giancarlo also eat a lot of carrots to look at the lights, but apart from that, that’s the lot. They are the parameters that have the biggest effect. Tyres, too, obviously.
Juan Pablo: About the same, really, yes, gear ratio and it all depends how much torque you have. If you look at an on-board camera from them in Bahrain you can hear there are corners where they have like no revs and it still pulled out of the corners where … it is just a characteristic of the engines and so on.