it will be hugely dependant on which dyno you use as to what correction needs to be applied to get a close estimate at the flywheel power imo.

there will always be people saying flywheel figures are rubbish I just ignore them and do as I please

surrey rolling road is a dyno dynamics dyno and known for being fairly accurate, certainly not generous anyway.


so here is the flywheel plot from my gtr at 1.4 - 1.6 bar of boost





now assumeing that 2wd correction was applied (which is the minimum it can add) then the wheel power for that run was about 710 WHP with 18% added for rwd losses that the dyno applies.


so we have a dyno dynamics dyno measureing 710 WHP from my car at 1.4 - 1.6 bar.
now heres a dynapack plot from my gtr on the exact same 1.4 - 1.6 bar tune



so dyno dynamics made 710 whp, dynapack made 812 whp.

so the dyno dynamics needs 130 hp adding to show correct flywheel power, dynapack needed 28 hp adding to show the correct 840 hp it has at the flywheel.

there we have the same tune run on dynos operated correctly with no fudgeing involved and the wheel/hub figures varied by 102 hp !


the tiny gains your talking about with the flywheel being lightened can easily disappear and more through dyno variation, if you didn't get it dynoed before the mods I don't think you will be able to make a good comparison now imo.

and your aircon will make no difference, yes you've shaved a little weight but when the aircon isn't active the clutch isn't engaged so the pulley spins freely, an air con pulley with no air con engaged wouldn't even sap 1 hp imo.