I'm tuned for 25psi spikes, but I really wouldn't be comfortable with more than that (my gauge only goes to 25, too). I just can't see risking a headgasket and possibly water pump when better studs don't cost that much.

 

This summer I ran my car basically at 100% WGDC on a gm bleeder, e70, 30+ psi(my JDM 3 bar doesnt see much past 28 or so). I did this because my car had some surging under high load and this actually "cured" it. Car pulled great but I can say there's not much to gain up there; however, like I said it solved my surging issues, seemed like the turbo really liked running that fast(counter-intuitive really). I am completely stock block IX, I recently tuned my car to run on 91 this winter at a conservative 21-22 psi.

So as far as headstud problems, its most likely over cautious behavior to replace them, but you really can't blame people for being over-cautious with expensive engines.

 

No, you are not trapped in a time warp...I thought I'd bring this old thread back to life.

Seems I've been seeing more reports recently about EVO engines bitting the dust on E85. Is that all or mostly from simply poor tuning?

So, what is considered a safe boost level limit for both engine and turbo?

And, more importantly, what are you guys with dynos seeing as the top of the efficiency range for the stock IX turbo on E85? Where does the incremental gain in HP per pound of boost added begin to diminish significantly?

Thanks,
Jim

 

poor timing.

for a evo9 turbo id say like 31psi for its max? since its about a twin scroll 16g.

pm johnbradley for the dyno question.