so im looking at dyno charts for stock 550i's vs 550's with performance parts... it looks like the dyno only show 285 hp at stock.. that to me seems like a GROSS overestimation on BMW's part or a terrible driver performing the dyno... right?




edit:

and now im retarded because i guess its 360 hp at the engine and 285 at the wheels? thats kind of dissappointing that im losing 75 hp in my transmission

 

Automatic or manual gear box?

You loose more with an automatic transmission then you will with a 6 speed.

 

This is a misconception many people have about manufacturers posting horse power on vehicles. Generally the HP given by companies is the HP of the engine block tested on it's own(Crank HP), when you do a Dyno it's the true horsepower at the wheel. One way to think of it is if you throw a baseball a far distance, when it first leaves your hand it's going to be going at max velocity and as it travels through the air it slowly slows down. The same goes with your vehicle, as the rpm moves from the transmission to axle and other numerous parts because of friction it will eventually start to slow down before it actually hits your wheels hence crank vs at the wheel.