Powerstation sometimes reads high, but sometimes is fine. I've been there 3 times, once a load of standard engines all hit above there quoted power figures, and all were approx 7% over so was easy to see how much it was over reading that day.
As for powerstations low atw figures, here's an explanation from one of the guys there. on why those figures you see are not true atw figures and hence show stupidly high tranny losses
It's a dyno wheel horse power figure, not a road wheel horse power figure.
If the car was on the road it would have one contact patch per corner, in the dyno it has two per corner so the drag is higher whilst in the dyo having it's tyres pinched between the two sets of rollers.
DynoDynamics rollers are much smaller and exhibit less drag and conversely show more wheel power.
Some dyno's do indeed have one roller and it's just a big drum, they are commonly know as Mustang dynos, and the car just accelerates a known mass (the roller) to get its figures. there are no eddy current devices used in that and no strain gauge.
Take it to the one we went to on the rr day only way to compare mate.
