donp

The conditons vary so much.

What was ambient temp? Barometric pressure? Elevation? Was the cooling fan in front of your car big enough to be effective? Was the dyno in calibration? What kind of fuel?

You can't assume your car was making 340 when you did the runs and just blindly use a correction factor to back into 340hp. Maybe conditions that day were such that you were making less than advertised. At that point, all your numbers are fubar.

Orangeblood

The driveline loss is not linear for all cars. But most tuners use 1.29 for the B6.

JDBlueAudiS4

AWE has dynoed 4 B6 S4's which all got within 1hp of each other. they havent done nearly enough to get a real number yet. Also unless someone pulls there engine and does an engine dyno and chasis dyno we will never really know. Its all just guesstimates. Hence why we really need to look at gains over base not a bogus conversion factor.

skidmark

or wasn't broken in completely when you dynoed first time

JDBlueAudiS4

the car had its first oil change prior to the first run.