timborx8

Kind of new to the whole turbo modifying thing but if i remove the cats, won't the turbo boost too much? do i have to modify the fuel mapping of the greddy e-manage or should i use a BOV recirculating type?

Fanman

Already running into bad backfire issues with the hi-flow cat. Would assume it would be that much worse without a cat. Tried to lean it out on de-accel (through Greddy Support tool software), but still backfired. Finally just pulled the hi-flow cat & put the regular cat back on. BOV has nothing to do with the cat. Also be aware you will get the CEL, even on the non turbo straight pipe most of the time.

rkostolni

So the back firing can't be tuned out? I would expect this with a straight pipe, but I wouldn't think it would be such a problem with a high flow cat.

Fanman

We tried. It was a bit better (about 30%) but it still popped a bit randomly. I really want this to be an everyday driver so I took it off. If you can take it, keep it on. To me the minor hp gain wasn't worth it.

Greddyturbo1

Hey Fanman, I have the Rotary Performance High Flow cat and I do not have any back firing, We have tweaked the tuning and currently tweaking the E0-1.. I'am running about 8.7psi boost, but am also running 100 octane...

Fanman

I try to preface my statements with "some/most" Greddy turboed cars are backfiring. I guess you would be in the not backfiring category. I'm not sure if the 100 octane gas has anything to do with it, or maybe you car just runs leaner naturally. We have pretty much leaned it out as far as we safely can & while it improved the backfiring issue it still did it randomly, so rather than gain a few hp & live with the popping, I just pulled it & put the stock cat backon.