What is the percentage of loss from the crank to the wheels? Also is it the same on every car? My buddy says his Porsche 996 is underated and actually puts down the advertised power to the wheels.
Thanks

 

There are plenty of cars that are underrated from the factory (and quite a few RX8s that are overrated j/k). Drivetrain loss differs between models for sure. As far as how it differs between two of the same model/year, there are too many factors without actually knowing what each of the motors is putting out for power. Considering manufacturing tolerances, sensor error, break-in, fuel, etc it is more than reasonable to assume that two Evos that roll off the assembly line next to each other can be making different power...by how much? I don't know.

Calculating your drivetrain loss is pretty much an educated guess...you can take your stock reported horsepower and divide it by your stock dyno'd horsepower...but now you've got to be careful of dyno numbers, etc etc.


In short ( I know it wasn't short ) your friend may be right, or the dyno may be wrong. How's that for a definitive answer?

 

More on topic: I believe the SRT 4s were putting down their advertised HP to the wheels as well as the 03/04 Cobras.

As far as drivetrain loss, transmission components, differentials (number and type), and other factors will impact the difference in power.

 

SRT-4 was putting more hp down than advertised when they were first released.....I remember reading the article, I know if it wasnt a neon I might have considered buying one a couple years ago....but I just cant get past the neon thing, no matter how quick they are for 20k....

 

If the 996 is underrated, it's not by much. My father had one and it could not keep up with my Evo after I put a catback on it and tuned it with an AFC. Porsches are typically pretty close to their advertised power rating.

-Paul

 

From what I've read on this forum over the past few years, there seems to be ~25% power loss on the Evo (AWD). It seems as if the power loss on RWD cars is smaller in the 15% range...