Originally posted by MxRacer:
brothers car makes 540rwhp on a mustang dyno at 11psi while running out of fuel. take it to a different tuner, and it now makes 500rwhp on a dynojet at 15psi with plenty of fuel.
go figure. 
Easy, he added more fuel to be safe but the added fuel reduced heat of combustion and therefore reduced power. If it wasn't detonating before even though it was leaner, he could gain some of it back probably by leaning it back out. It isn't necessarily just the dyno though at 500+hp it could be run to run and dyno to dyno variation too.
Former owner of '99 CSVT - Silver #222/2760
356/334 wHP/TQ at 10psi on pump gas!
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'05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red
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