[Sunny]

Originally Posted by monster

If I can remember correctly the Ferrari 250 GTO has a 2.953L V12 engine which produces 300 bhp @7500rpm so that gives it a 101.6 bhp which is just over the 100 bhp/liter. Ofcourse the measurement equipment back then is not as accurate as the ones we have now.

Thanks didn't know that. Do you know what is the redline for that engine, I would guess it is above 8000. I actually found that there are other engines that make 100hp/l at < 8000 RPM like the RS4 engine which reaches the mark at 7800 RPM... but its redline is at 8250.

[Monster]

Actually I just checked the offical Ferrari website, the engine produce max hp at 7700rpm, so the redline is probably around 8000 rpm or above.

[vedjo01]

Considering piston speeds of road going cars,I think that 7500 rpm is reasonably high border to call engine excedding that limit to be high-reeving.I have seen somwhere that even E46 M3 engine piston speeds ar almost equal to F1 cars motor(Speed figure was 25m/sec,I think..),correct me if I´m wrong.That is quite an achievement IMO .

[Giannis]

I can rev up to 6500rpm with my Volvo (i have done it only twice though), so anything less than redline at 7500rpm is not high-reving. Period

[martinbo]

Originally Posted by vedjo01

Considering piston speeds of road going cars,I think that 7500 rpm is reasonably high border to call engine excedding that limit to be high-reeving.I have seen somwhere that even E46 M3 engine piston speeds ar almost equal to F1 cars motor(Speed figure was 25m/sec,I think..),correct me if I´m wrong.That is quite an achievement IMO .

It all depends on the engine stroke length. Here are some comparative internal pistons speeds: If you want more for a specific model just provide me with the model no, the stroke length and the max power rpm.

Note that these are not the maximum piston speed for the engines but a more relevant listing based on where the engine produces its maximum power. An RS4 for example, revs to 8250 rpm meaning that its piston speed reaches 25 ms-1

Model Stroke (mm) Stroke (Inch) Max power rpm Piston speed (km/h) Piston speed (m/sec)

C320 CDI: 88.3 3.48 4200 44.55 12.37
SL 500: 84 3.31 5600 56.50 15.69
CLS 55 AMG: 92 3.62 6100 67.31 18.70
330i (N52): 88 3.46 6600 69.60 19.33
M5: 75.2 2.96 7750 69.92 19.42
Corvette Z06: 101.6 4 6200 75.59 21.00
S6: 92.8 3.65 6800 75.65 21.01
63 AMG: 94.6 3.72 6800 77.10 21.42
S4: 92.8 3.65 7000 77.88 21.63
M3 CSL: 91 3.58 7900 86.20 23.95
RS4: 92.8 3.65 7800 86.78 24.10
S2000: 87 3.43 8300 86.77 24.10
F430 CS: 81 3.19 9000 87.51 24.31

[vedjo01]

Thx,martin,for info..I appreciate it..If are we on this subject now,I was wondering..Is it possible to make engine with higher piston speed(above 25m/sec) without lossing low and mid torque?If I´m correct,F1 engines produce their power soley or revs and have relative small stroke so useable torque is at high engine speeds .You have to uderstand that my knowlege in this area is pretty limited so basicly I would love to know little more about the subject at hand ..

[martinbo]

Ooo vedjo01, I can attempt to answer your interesting questions but I fear that I will soon be out of my depth on the technical front.

What I do understand is that achieving the optimum performance from an engine is a very fine balancing act.

It is possible to get engines to produce higher internal piston speeds simply by getting the engine to rev faster or increasing the length of the stroke or both. What is more difficult to understand is the effect of piston speed on forces acting internally on the mechanical components. Because momentum increases as speed increases, the forces acting on the mechanical components increase accordingly making them more susceptible to stress failure. So, if you're to increase the speed of the piston then one has to make the piston and associated components as light (and strong) as possible to withstand these forces, yet at the same time, also strong enough to cope with the force of combustion.

I don't think that by increasing piston speeds you will necessarily lose torque; torque is a product of displacement and not piston speed. Increasing piston speed will produce more power since this is a product of either:

- Stroke length
- RPM

I reckon, the main consideration when it comes to upping piston speed is the increased likelyhood of mechanical failure. Low range and mid-range torque is a different factor altogether.

Interestingly, here are some other piston speeds to put things into perspective:

1098 S 64.7 2.55 9750 21.05
GSX-R 1000 59 2.32 12000 23.57
F1 2400cc 39.75 1.565 19000 25.18

I don't know of an engine that has piston speeds much higher than 25.5 ms-1.

[vedjo01]

Thank you..I appreciate it..
It´s really fasciniting thing to read some tehnical stuff from a man like yourself..

[martinbo]

Originally Posted by vedjo01

Thank you..I appreciate it..
It´s really fasciniting thing to read some tehnical stuff from a man like yourself..

Thanks for the kind word vedjo01, sadly that's about the limit of my technical repetoire! For more accurate and detailed answers I'd suggest emailing the technical editor of well known motoring publications...

[NarutoRamen]

I'll go for the 7500 rpm as a start. Considering my honda's red line starts at 6500, it's just nor right to call a grocery getter a High-revving car. know what I mean? Also, with today's technology we should be able to hit 7500 without putting too much stress on the engine.

Of course that doesn't mean ride around your neighborhood in 1st gear at 7500rpm...that would be stupid.