I just recently tuned the ride and pulled out 507whp/420tq @ 25psi on E85 (70% ethanol). Last April I had it tuned on E85 and it put down 520whp @ 26psi. With the cooler temps in the winter, I started to max out my injectors at 100% duty cycle in the upper RPMs and began leaning out. I upgraded to a Walbro 400 and retuned the car. I was a little disappointed by the numbers and think that it may be due to the lower ethanol % that is at the pump right now, but I think that even if it was true 85% ethanol that I would not have seen that much of a gain.

It seems that I have maxed out this turbo. At 22psi we got 491whp, and bumping it up to 25psi only saw 507whp. I wanted to know if anyone has upgraded this turbo and what kind of gains have been seen. I was thinking of switching to a T4 exhaust housing to alleviate some of the back flow. I have also seen shops upgrade this turbo with a billet compressor wheel and basically turning it into a GT35. Would like to hear others experiences with this turbo. TIA.

 

Just sell it and go with a larger turbo. I would just buy a Gt3582r.