How much HP from maxed out S4
 

Hello,

Just wanted to know if anyone has a proven S4 with high HP numbers??? What are the weak points in the S4 when the HP #'s start to rise??? Can they achieve the 400 HP like the S5??? Also what kind of fuel was used to achieve the HP???

Thanks for any info...

No problem at all making 400HP on an S4 block. The rear iron is a bit weaker, true, but as long as the engine is tuned properly it won't be a big deal. For that matter, the tune is always the most important regardless of which engine series you are building.

You're going to want to be running 91 or 93 octane for all high HP turbo rotary builds.

WOW!!!

Thanks for the info Aaron, I had no idea that was possible with a S4. So how about 250 HP with stock porting and stock internals??? I'm pretty sure that can only be achieved with a forced induction system or a ridiculously perfect tuned N/A.

Not really going to happen on a stock ported NA. 200HP is about the limit there when the tune is perfect.

250HP is easily achieved by about 10 PSI on the factory turbo and a good tune.