2008 Le Mans 24 Hours preselections

[henk4]

Originally Posted by Kitdy

Ok, so does that mean Pratt and Whitney will still run a GT1

they will run jet engines...

[Kitdy]

Originally Posted by henk4

they will run jet engines...

Well that was a monumental error.

[Kitdy]

Ok, I know this will maybe be torn down as stupid or faulty or ridiculous or worse but I intend this post to give a rough estimate of how things in LMP1 are in terms of diesel/gas engines. Bear with me please, it is a little unorthadox and not thought out with an auto engineer's mind.

So it all started when I started reading the rules for the ACO LMP1 class. I saw the limits per engine in volume. 6L for naturally aspirated gas engines, 4L for supercharged/turbocharged gas engines, and 5.5L for the supercharged/turbocharged diesel engines. I have selected the vital stats of each of these engines, including hp + lb.ft. of torque for a reason I'll get into later. I then used the hp/L of these engines to determine what roughly, their hp would be if the two smaller gas engines were expanded to full size in the regulations.

For example:

696 hp at 6L ---> this stat represents the 5.5 L engine had the same hp/L and was expanded to 6L.

As I first started to mull over these figures, I began thinking about the difference from the big low-down torque of diesels in comparison with the more peaky gasoline engines and they way their power curves would look, then I began to think of a possibly better way to determine the performance of an engine - the area under the horsepower curve, with units of hp X rpm. This would seem to describe the overall performance of the engine better than peak hp would, am I correct? Am I way off in this manner? Anyways, as a rough estimate for this hp X rpm unit (as I cannot calculate the hp X rpm because I do not have a dyno computer and the numbers for these cars) figure I instead added hp and torque of the engines to see what had better figures, unsurprisingly, the diesels had both more torque and more hp and thus were far and above ahead of the gasoline contenders. Basically, LMP1 as it stands is not fair, as the diesels have far more torque and hp and a better power curve. The rules need to change to make it fair again as the smaller teams cannot afford to run diesel engines.

Even though the peak theoretical hp I predicted for the two diesel cars is similar to the hp of the diesels, as they have flatter, beefier power curves, they have more power available at lower revs, and thus, more speed. Compare the hp + lb.ft. of the two diesels to the two gasoline engines, the difference between the two averages is about 400 hp + lb.-ft., relating th t back to hp X rpm, that is a large amount discrepancy between the gas and diesel engines.

Finally, calculating the hp + lb.-ft. for the Lola B06/10 AER if hp/L and hp/lb.ft. remains relatively constant and the size of the engine is increased to 5.5 L (the same size as the diesel), you have roughly 1700 hp + lb.-ft, now it has tilted on the side of gas engines. The happy medium therefor lies at somewhere about the 4.6-5.0L range for turbo gas engines and if the diesel engine size remains at 5.5L.

The four contenders:

Audi R10 TDI
5.5L Turbo Diesel V12
650 hp
811 ft.-lb.
118 hp/L
650 hp at 5.5L
1461 hp + lb.-ft.


Lola B06/10 AER
3.6L Turbo V8
600 hp
516 ft.lb.
167 hp/L
668 hp at 4L
1116 hp + lb.-ft.

Pescarolo 01
5.5L Naturally Aspirated V10
640 hp
485 ft.-lb.
116 hp/L
696 hp at 6L
1125 hp + lb.-ft.


Peugeot 908 HDi
5.5L Turbo Diesel V12
700 hp
885 ft.-lb.
127 hp/L
700 hp at 5.5L
1585 hp + lb.-ft.