I went to Dynojet (model 248 C) last week and the outcome was 206 on the wheels and 233 on the Crank. Is that good? Why do i have 7 ps less than the factory figure in the crank?

 

How do you measure at crank?

 

206 @ the wheels is somewhat on the high end already. Dynojet also tells the hp at the crank? I didn't know that. If your car makes 206 at the wheels, that's good enough already. You're not really getting ripped off at the crank. HP at the wheels is all that matters. Then just calculate the 15% loss, and you're making about 242 at the crank. Not bad!!!!!!

 

Thanks yellafever!!

 

I Do not know godai but Dynojet can measure losses. But keep in mind that the mechanic told me that only wheel power is accurate.

 

It's not always 15% loss with a manual. For instance, on many BMW's and especially the Toyota MR2-S, drivetrain loss is around 9-11%. My Spyder, stock, dyno'd at 122.8hp Most others dyno in the 120-122 range. I would summize in the Spyder's case, it's the fact that it's mid-engined but I wouldn't speculate on the BMW's, which appear to have very well-engineered and efficient transmissions.

 

I just can't imagine how a dyno can calculate losses/crank power at the wheel.

 

the car will probably get more power to when you are moving because there is more air cooling down the engine. am i right?

MAtt