6 replies to this topic

[Alex]

Alright, here's the question...

As you know specific torque is amount of torque per liter of capacity. I'm only looking at the naturaly aspirated racing engines.

Using the standard power/torque formula's, one can conclude the fact that is almost unbelievable.

aproximations...
BTCC - 320hp @ 8500, 280Nm @ ???
F1 - 800hp @ 17000, 350Nm @ ???

2.0 4 cylinder 8500 rpm limited engine from BTCC has got more specific torque the 3.0 V10 F1 engine!!!

I played quite a lot with those formula's and I still can't believe it! Those numbers I put are not accurate of course, but I couldn't have been more than a few percent wrong. In fact, of all types of NA engines in the world, those in 2.0l touring cars offer the most specific torque.

How is that possible I ask you if we all know that F1 engines are the most advanced.

Square pistons maybe, better compression ratio?

[This message has been edited by Alex (edited 03-16-2000).]

[IndyIan]

Alex,
I think the answer is that F1 engine designers have no interest in torque, they want horsepower. Therefore they sacrifice torque for horsepower with extremely over-square engines which require high rpms to make what little torque they can.

I think you can think of specific torque as an engines efficiency, not in terms of fuel, but by how much power it makes sucking in a certain volume of air. (I am not totally sure about this, hopefully some engineer will help us out)

Therefore the touring car engine designed to run at a lower rpm should have a higher specific torque because the internal frictions are much, much less than the F1 engine running at twice the rpm with twice as many cylinders.
It is probably amazing that the specific torques are as close as they are since the internal frictions of an F1 engine at full song are probably staggering from just the sheer speed of the gases rushing in and out and the speed of which the oil circulates.

I hope this helps.

[desmo]

MN, Are you sure they're not trying to create a flat HP curve? IndyIan's post is essentially correct. The biggest secret of the last 10 years in F1 as far as HP has been to compartmentalise the crankcase into 5 (in the case of a V-10) seperate chambers to eliminate pumping losses in the fore and aft direction.

[davo]

Alex

One valid way to look at the engine development is HP/LITRE/1000revs. If you like a breathing and mechanical efficiency measure.

Based on your figures

BTCC 18.8 BHP/L/krevs
F1 15.7 BHP/L/krevs

I think your figures may be out a little perhaps up 10HP for the BTCC and down 50-80HP for the F1 compared with best in class. This would actually bring them even closer.

Am I suprised that the BTCC "out performs" F1 - not really. Keeping engines efficient at revs is very difficult that F1 engines can breath as well as they do at such incredibly high revs is tribute to the design.

BTCC is no engineering back water.

[desmo]

Can anyone post an image of the Honda F1 V-12 cutaway published in R&T? I threw away my copy and would like to revisit it to check on a couple of things.

[Billy Gunn]

Alex, Davo,

You forgot the F3000 engines:-

520 bhp, 3 Liter, 9,000 limit (max power at 8,750 due to Monk limiter)

By my reckoning this equates to 19.8 Bhp/Lt/Krev

Monk'shavedirtyhabits

Billy G

[desmo]

F3000: Not to mention bmeps over 17 bar.