Has anyone run 20-24psi on a GT35/40? Nocab says 430@15.5psi, RPM Performance says 430@10psi(dyno) all these guys with 35/40, and no one has the balls/setup to turn it up to a modest 22psi, what gives???? Carl

it does take balls..... and race gas.... and somebody that knows how to tune for 20 psi without needing a new engine https://www.nopistons.com/forums/pub...DIR#>/wink.png

I'm the one who made 430 to the wheels at 15 psi. Its not that I don't have the balls to turn the boost up, but I keep getting setback. First it was a wastegate problem, that would cause me to overboost. Then a line to the profec b got severed and cause more overboosting. Finally got it boosting solid and was able to make 430hp. Was running good for a while, the it got colder and the car got rich as hell and slower. Need to tune the temp correction maps. I had an appointment to dyno tune again the 7th this month, but broke the differential the night before. Was planning to try 20 psi. Right now I'm waiting on a replacement to arrive. Should be here next week. Car still has to go to body shop, and the weather is getting ugly. I'm moving in January so I might just wait till then to tune and dyno again. I'm pretty confident that this turbo can make 500hp to the wheels. I'm 70 hp away and got alot more boost to play with.

Just stirring the pot really. I am ready to order a GT35/40 from RPM, just trying to get a read on the real power potential of this turbo. My goal as anyone with a computer now knows is 550rwhp, in a turbo usable for road race. RPM recommended the 35/40, Precision recommended a straight GT40 .77 inducer,.82 exducer, don't know ar(available January). Horsepower in a box suggested the alternative of a to4 with a 1.32ar, and a T66 compressor in a .70 cover(they prefer the GT, but state it is not currently available). HP in a box also stated that they felt a GT40 was too large. Another turbo I was considering before the GT was a T66 1.00ar Q trim. Calling all cars, WHO IS MAKING THE POWER???

For road racing? Don't go overboard on th exhaust side. Divided p trim a/r 1.00 housing should be suffecient.

500rwhp with a ported motor looks pretty easy with the GT35/40. I've got a few kinks to work out and will get a dyno sheet up for those non-believers.



I have serious problems keeping the car going in a straight line when I punch it from 80Mph in 3rd @ 17psi. This is not high-rev, clutch drop @ 80Mph, this is drop to 3rd, stabablize the car, then punch it...as soon as the boost builts the rear end breaks loose even on 50F days with the sun out. I'm running what I consider pretty good tires, Toyo Proxy T1-S's, 255x35x18, about 8k miles on them. 400rwhp doesn't cause this. 450rwhp comes close under non-ideal conditions (would you agree Ihor?). I'm betting I'm putting down > 450 with my current conservative AFR & timing tune (the Blitz Powermeter being confirmed accurate with a dyno on my old engine also shows this).



I realize though, nothing will speak louder than a dyno sheet...I'm working on it!



K

good work. can't wait to see some 500+ numbers https://www.nopistons.com/forums/pub...#>/biggrin.png

What do you mean by "comes close under non-ideal conditions"?

With your setup, almost 450rwhp... you should come close to breaking loose the rear end in 3rd as you built boost...



I'm not talking breaking loose on the 2-3 shift...I'm talking, cruising along in 3rd and punching it, as soon as the boost comes online, my backend is all over the place... https://www.nopistons.com/forums/pub...#>/biggrin.png



k

Your using 255 width tires? Jesus! I can break traction with 275 Nitto's in 3rd gear...so I can only imagine what your doing! https://www.nopistons.com/forums/pub...IR#>/boink.gif