Originally Posted by
Z28ricer
That manifold sure seems to be flanged for an external wastegate, looks like for a tial 38mm, according to the information tial has available. If he wants he can go as low as 3.62 psi.
Who doesnt know what they are doing now ?
Even still, it'll be interesting to see whether you can divert enough exhaust through a 38mm hole to keep the turbo down to 5-6psi. If you can't, that's the definition of boost creep. The shitty part about boost creep is that it happens higher in the rev range, where peak power is made and injector duty is at it's max already.
Just a point of info: A similar setup, 3071 50t with .63ar exh setup on a FR manifold, had a hard time keeping boost under 10psi with a 40mm gate.
I'm not dicating that you're going to have boost creep issues. But, if 6psi = 250whp = 99% duty cycle = 12.0AFR, then creeping to 9psi is going to put your AFR's up around 15 and it'll be a race to see which goes first: gasket or pistons.