Robby

Good points Danno... I've always assumed that lowering resistance by reducing rotational and frictional drivetrain parts, would increase power. When I say this, I mean that more of the engine's power would actually get to the ground- basically, removing weight from such parts would free up the power that the engine already has, thereby reducing it's losses.

This also brings up the G-Tech question. I have never used them for measuring HP, as I never really believed in them for that purpose. Everyone says they measure power @ the wheels, which is true, but... If you went from tires to slicks, then you would get through the 1/4 several 1/10's quicker. I assume the G-Tech would then show you a higher HP reading, as it calculates it's HP readings by moving X amount of weight a specific distance in a certain amount of time. But, in this case, you haven't actually added any power. Some say that, yes, it's still true, that you got more of the engine's power to the ground. But, on a chassis dyno, you don't have to worry, really, about the tires slipping on the huge rubber rollers, so it wouldn't show a difference b/t the slicks and the regular tires. Unless, one or the other were a good bit lighter, which would allow the engine to spin the rollers a little faster.

As for the question about Milledge- I'm not postive, but I'm pretty sure that he just has an engine dyno- I had forgotten about that when I had sent my last reply. I THINK he somtimes uses a friend's wheel dyno that is somwhat close by, and has compared the two that way. I'm not sure on this, but he did tell me a story about his dyno situation, and had mentioned the drivetrain loss in the same conversation. He also mentioned that he had compared 951's w/both MAF's, AND, ported and polished heads (not shaved), and that neither really helped TOO much, even on 400HP engines...

Anyway, sorry this was so long,
Later,
Robby

Danno

Yeah, I think this is true too, just difficult to measure. You have to distinguish FORCE (torque) from POWER, which is force per unit time. Dynos measure force by sensing acceleration of a known mass, or braking-force. Then it computes power based upon how much acceleration of the known mass/braking-force in a set amount of time. So with lighter parts, no more torque would register on the dyno (force), but HP will increase because you've got less engine-mass to accelerate. But the HP increase will be different depending upon the mass of the dyno's drums or its braking-force.

So I guess this is where the debate on lightweight parts started. Depending upon the dyno you use, it may show no HP gains, or varying amounts with various dynos. But high-speed rotational parts have so much more inertia than non-moving parts, that losing weight in the engine is probably the most beneficial. I think the ultimate test would be data-logged acceleration (with no tire slip, maybe 5mph+ roll-ons) and top-speed runs, then compare to stock car.