I was thinking about getting a stage 1 BNR upgrade but my s4 is mostly stock, full 2 1/2 inch straight exh,hks power suction intake(pretty much a mushroom shaped filter), emissions removed,blitz bov,and a old school hks FCD(not installed) how bad or if any the consequences of going to a stage 1 Turbo will be? any help would be greatly apprecited.

 

A hybrid turbo on stock fuel is a bad idea. Stock boost levels should be fine, but any more than that will blow the engine.

 

Talk to Brian at BNR for suggestions on fuel/ECU upgrades to run with the Stage 1.

 

Thanks alot ill give him a call.

 

what is the possible max output on a stock turbo with supporting fuel mods?

 

im pretty sure that over 12 psi would blow your engine

 

Maybe the following will give you a useful datapoint.

My S5 Turbo with stock turbocharger (highly ported wastegate), HKS intake, RB REV-II turbo-back exhaust system, and FCD dynoed at 222 WHP/205 ft-lbs torque at 7 psi. No other engine mods.

I recently installed a BNR Stage 1 turbocharger (mildly ported wastegate), Supra TT fuel pump, RC 750cc secondary's and an Rtek 1.7 chipped ECU. These were the mods suggested by Brian. I'm hoping to dyno around 270-280 WHP at 10-12 psi boost with these mods.