30 replies to this topic

[DVtriple6]

Does anybody have the slightest idea what they may be? I've wondered for a long time and since they are playing CIA on eachother I've never had a real answer. Think it can be as high as 1500nm2?

[murpia]

Peak engine torque is likely to be in the range 250Nm to 300Nm depending on a host of other factors.

Regards, Ian

[DVtriple6]

Uh..? Yopu sure about that? Isn't that like nimble streetcar range? as in somewhere along 200-400 hp?

Doesnt sports cars like the SLR have nearly a 1000nm of torque? Or did I miss something

[murpia]

I think you missed something...

700bhp at 19,000rpm = 262Nm

A basic automotive engineering textbook should help.

Regards, Ian

[DVtriple6]

Oh I was asking about max torque but yeah, thanks.

[PirateTaco]

simple answer:
well since current reg F1 engines are only 2.4 litres and since you can only get a maximum of 100Lbft per litre from a NA engine the maximum possible is 240Lbft.

[murpia]

Yes, 240lb-ft = 325Nm sounds about right for peak torque.

Regards, Ian

[J. Edlund]

Current F1 engines produce about 750 hp at about 18,500 rpm. That means a torque output of about 280 Nm. This correspond to a bmep of about 14.6 bar. Maximum torque is probably around 15,000 rpm and I would assume it's done with a bmep of about 0.8 bar or so more. That would translate into a maximum torque of close to 300 Nm or 125 Nm/liter of displacement.

[DOHC]

So that would be about 650 hp @15,000 rpm, increasing to 750 hp @18,500 rpm? How wide is the typical power band?

[Scotracer]

Originally posted by DOHC
So that would be about 650 hp @15,000 rpm, increasing to 750 hp @18,500 rpm? How wide is the typical power band?

When Martin Brundle drove the Super Aguri SA01 (or 2, I forget) he was surprised by how linear the engine was; with a lot more mid-range power than he had expected. So perhaps they aren't as peaky as we suspect?

[DVtriple6]

Originally posted by Scotracer


When Martin Brundle drove the Super Aguri SA01 (or 2, I forget) he was surprised by how linear the engine was; with a lot more mid-range power than he had expected. So perhaps they aren't as peaky as we suspect?

Well apparently most F1 engines have an output explosion on the high rev band but there may be some exceptions such as the Super Aguri perhaps. While mid-range power is nice for things like endurance races I think F1 cars are better off with this "explosion" of power, am I right? After all they have 7 speed gearboxes, well most of them anyway. Not too sure about the slowest low budget teams though..

As for torque, somewhere around 300nm2 (that's newtons per square metre right?) seems pretty low, doesn't the LMP1 class have around 1200nm2? With around 700+hp? Those are the diesels yeah, but still. Surely the F1 cars must pack a punch on the torque side? Or did I get my measure screwed up or something?

[Goran Malmberg]

Originally posted by DVtriple6

As for torque, somewhere around 300nm2 (that's newtons per square metre right?) seems pretty low, doesn't the LMP1 class have around 1200nm2? With around 700+hp? Those are the diesels yeah, but still. Surely the F1 cars must pack a punch on the torque side? Or did I get my measure screwed up or something?

On a naturally aspirated engine Tq is very much proportional to cui. And it is Hp numbers that tells acceleration capacity. Hp is work.
As the engine works at high rpm, gearing it down still gives rear wheel big Tq numbers.
Goran

[zac510]

LMP1 are turbo diesels, too. Different kettle of fish!

[murpia]

Originally posted by DVtriple6
As for torque, somewhere around 300nm2 (that's newtons per square metre right?) seems pretty low, doesn't the LMP1 class have around 1200nm2? With around 700+hp? Those are the diesels yeah, but still. Surely the F1 cars must pack a punch on the torque side? Or did I get my measure screwed up or something?

The SI unit of torque is Nm. Newtons per square metre (N/m^2) is the SI unit of pressure, the Pascal.

There's no reason to expect an F1 engine to have more torque than an LMP1 diesel. The F1 engine is revving over 3 times faster than the LMP1 diesel.

Or did you not realise Power = Torque multiplied by Rotational speed?

In SI units that's Watts = Nm * radians/second

See post 4...

Regards, Ian

[marchof73]

I was always fascinated ,during he 3 litre V10 era to see them pulling away from certain corners at 9,000 revs,and going up to 20,000.11,000 rev band,quite incredible torque and flexibility
Ian

[phantom II]

Depends what you run it on. http://alternativefu...urces/a/gge.htm

Originally posted by DOHC
So that would be about 650 hp @15,000 rpm, increasing to 750 hp @18,500 rpm? How wide is the typical power band?

[Scotracer]

Originally posted by DVtriple6

Well apparently most F1 engines have an output explosion on the high rev band but there may be some exceptions such as the Super Aguri perhaps. While mid-range power is nice for things like endurance races I think F1 cars are better off with this "explosion" of power, am I right? After all they have 7 speed gearboxes, well most of them anyway. Not too sure about the slowest low budget teams though..

As for torque, somewhere around 300nm2 (that's newtons per square metre right?) seems pretty low, doesn't the LMP1 class have around 1200nm2? With around 700+hp? Those are the diesels yeah, but still. Surely the F1 cars must pack a punch on the torque side? Or did I get my measure screwed up or something?

Apparently not.

And they are around 320Nm Torque. Torque on an engine that isn't Turbo or supercharged is very much dependent on engine size. As F1 engines are only 2.4 litre...they don't make much torque. Diesel LMP1s on the other hand are 5.5 Litre and twin-turbo charged...much, much more torque.

Also, remember power = torque (lb.ft)xrpm/5252. Diesel LMP1s rev to around 4,500rpm whereas F1 rev to 19,000rpm.

Peugeot 908 HDI FAP:

1200Nm = 885lb.ft @ 4000rpm

Power = 885lb.ftx4000rpm/5252 = 674BHP @ 4000rpm

Guessing that peak power is at 4,500rpm, we can theorise that power is about 700BHP.

F1 car:

300Nm = 221lb.ft @ 15,500rpm

Power 221ft.lbx15,500rpm/5252 = 652BHP @ 15,500rpm

Guessing peak power at 18,500rpm and it is 750BHP...that would suggest that 96% of peak torque is sustained at this rpm...now that's a wide/flat torque curve.

[OfficeLinebacker]

Do they tune the diesels for more top end for LeMans?

With the chicanes installed the Mulsanne isn't the factor it would be left whole.

[murpia]

Originally posted by OfficeLinebacker
Do they tune the diesels for more top end for LeMans?

With the chicanes installed the Mulsanne isn't the factor it would be left whole.

Probably fuel economy dominates the engine tuning and gear ratio choice, maybe even the drag level.

This year it appeared Peugeot upped the boost for qualifying compared to Audi. So, we can speculate that in race trim neither car runs at max ACO permitted boost pressure, and therefore not at the reputed 700bhp+.

I think the Audi's were running longer between pitstops this year than Peugeot, but I have no concrete stats. Is anyone able to confirm this?

Regards, Ian

[Ben]

First Audi home #2 32 stops, total time stopped 31m56s
First Pugeot home (same lap remember) #7 36 stops, total time stopped 41m40s

Ben

[MikeTekRacing]

quite hard to compare though...we don't know how many driver changes they made, or if there was an extra stop for tyres, or some other car trouble/time spent in pits for fixing small issues
however, we can most safely argue the audi was more fuel efficient. by how much i guess it's a little difficult to know

[Ben]

#7 first stop, fuel only at 15:34
#2 first stop, fuel only at 15:38

Looks like it was a lap per stint better on fuel.

Ben

[Ross Stonefeld]

As is the case at Le Mans, the car that did the least amount of time in the pits won. I think Peugeot lost some time in a few problem stops in addition to the simple fact they made more of them.

[DOHC]

Originally posted by Ross Stonefeld
As is the case at Le Mans, the car that did the least amount of time in the pits won. I think Peugeot lost some time in a few problem stops in addition to the simple fact they made more of them.

Not sure if I'm qualified to comment on this, but to me this seems to be the correct analysis.

[Engineguy]

It was said that each of the Peugeots was backed into the garage a few times just to blast out the radiators thoroughly, accounting for a big chunk of pit time difference vs. Audi. A result of smaller radiators chosen for aero reasons, aggrevated by the stickiness of wet track crud.

[zac510]

Originally posted by Ross Stonefeld
As is the case at Le Mans, the car that did the least amount of time in the pits won. I think Peugeot lost some time in a few problem stops in addition to the simple fact they made more of them.

There was a quote in the Audi press release that their car could do 12 and the Peugeot only 11.

[pingu666]

the audi's mostly did a lap longer stints, and i think the mulsane straight isnt the fastest point anymore , its the straight after the mulsanne that goes to indyanapolis...
207.5 vs 215 at the speedtraps if i remmber correctly

[marchof73]

Originally posted by Engineguy
It was said that each of the Peugeots was backed into the garage a few times just to blast out the radiators thoroughly, accounting for a big chunk of pit time difference vs. Audi. A result of smaller radiators chosen for aero reasons, aggrevated by the stickiness of wet track crud.

Peugot were certainly dragging the cars into their garages during the overnight period.The loss was about 1 minute per car-significant
Ian

[Scotracer]

I found this in an old thread (in the archive) :

Pressure ref kh Temp Humidity
998.32 mbar 1.0111 20 ‹C 49%
RPM Torque (m.kg) Torque (N.m) kW HP (met)
8500 22.53 221.02 196.73 267.48
9000 24.09 236.32 222.73 302.83
9500 25.12 246.43 245.16 333.32
10000 25.90 254.08 266.07 361.76
10500 26.80 262.91 289.08 393.04
11000 28.75 282.04 324.88 441.72
11500 32.43 318.14 383.13 520.91
12000 32.90 322.75 405.58 551.43
12500 33.24 326.08 426.84 580.35
13000 34.17 335.21 456.34 620.45
13500 34.70 340.41 481.24 654.30
14000 35.00 343.35 503.38 684.40
14500 35.10 344.33 522.84 710.87
15000 35.36 346.88 544.88 740.83
15500 35.35 346.78 562.88 765.31
16000 34.96 342.96 574.63 781.28
16500 34.32 336.68 581.74 790.95
17000 33.75 331.09 589.41 801.38
17250 33.23 325.99 588.87 800.64

This is for the Ferrari F2000. As it is a 3.0 V10 but still N/A one can assume the current V8s would be 80% of this, so:

346.88Nm x0.8 = 277.50Nm @ 15,000rpm for V8

277.50Nm = 204.67lb.ft @ 15,000rpm = 584.54BHP @ 15,000rpm

This would correlate with 720BHP @ 18,500rpm if peak torque is sustained. Since the general consensus is that the current engines make over 720BHP one would assume the torque is higher than it was back in 2000 (which is possible with more efficient combustion chamber/valvetrain designs).

There we go...

[J. Edlund]

Originally posted by DVtriple6

Well apparently most F1 engines have an output explosion on the high rev band but there may be some exceptions such as the Super Aguri perhaps. While mid-range power is nice for things like endurance races I think F1 cars are better off with this "explosion" of power, am I right? After all they have 7 speed gearboxes, well most of them anyway. Not too sure about the slowest low budget teams though..

As for torque, somewhere around 300nm2 (that's newtons per square metre right?) seems pretty low, doesn't the LMP1 class have around 1200nm2? With around 700+hp? Those are the diesels yeah, but still. Surely the F1 cars must pack a punch on the torque side? Or did I get my measure screwed up or something?

Based on earlier engines, 90% of max torque is reached at 12,000 rpm or so, giving a nice powerband between 12,000 and 19,000 rpm for full throttle acceleration.

During the end of the V10 era a F1 car had enough power to overcome the grip at speeds below about 150 km/h. This meant that acceleration was grip limited to this speed. So, from this point of view engine power at the lowest engine speeds was not that important, even though these speeds were used. Today F1 cars are a little less powerful, so for low speed acceleration the importance of engine power has increased.

Generally a suitable powercurve is found through simulation. You want the powercurve that result in the fastest lap times with the car you have.

The diesels that are used on Le Mans have a displacement of 5.5 liters. In addition to that they are turbocharged. Don't remember the exact boost pressue, but I seem to recall that it's 2 bar absolute or so. That makes the engine comparable to a naturally aspiranted engine with a displacement of about 11 litres. If we use 1200 Nm and the 11 litre figure to calculate a bmep, we find that these engines produce a "naturally aspiranted engine corrected" bmep of about 13.7 bar; sightly less than a F1 engine although its different design. This confirm something we already knew; piston engines, powered by either diesel or gasoline produce a similar maximum bmep figure (or torque per displacement) when corrected for boost pressure.

Originally posted by Scotracer
This would correlate with 720BHP @ 18,500rpm if peak torque is sustained. Since the general consensus is that the current engines make over 720BHP one would assume the torque is higher than it was back in 2000 (which is possible with more efficient combustion chamber/valvetrain designs).

The main reasons for the increased power is most likely increased volumetric efficiency (larger bore, larger valves and other improvements) and reduced frictional losses.

[Scotracer]

Originally posted by J. Edlund


Based on earlier engines, 90% of max torque is reached at 12,000 rpm or so, giving a nice powerband between 12,000 and 19,000 rpm for full throttle acceleration.

During the end of the V10 era a F1 car had enough power to overcome the grip at speeds below about 150 km/h. This meant that acceleration was grip limited to this speed. So, from this point of view engine power at the lowest engine speeds was not that important, even though these speeds were used. Today F1 cars are a little less powerful, so for low speed acceleration the importance of engine power has increased.

Generally a suitable powercurve is found through simulation. You want the powercurve that result in the fastest lap times with the car you have.

The diesels that are used on Le Mans have a displacement of 5.5 liters. In addition to that they are turbocharged. Don't remember the exact boost pressue, but I seem to recall that it's 2 bar absolute or so. That makes the engine comparable to a naturally aspiranted engine with a displacement of about 11 litres. If we use 1200 Nm and the 11 litre figure to calculate a bmep, we find that these engines produce a "naturally aspiranted engine corrected" bmep of about 13.7 bar; sightly less than a F1 engine although its different design. This confirm something we already knew; piston engines, powered by either diesel or gasoline produce a similar maximum bmep figure (or torque per displacement) when corrected for boost pressure.



The main reasons for the increased power is most likely increased volumetric efficiency (larger bore, larger valves and other improvements) and reduced frictional losses.

Yes. I had been plugging in numbers for general diesels trying to work out why they produce so much torque and it should have been obvious in the first place -- force induction. I would really like some dyno results for a current V8...what have they got to lose? The engines are frozen anyway!