Searching for the right size turbo
Searching for the right size turbo I'm strongly considering a sbc457turbo build for my ta. This will be on the street 90%of the time so don't want to get a turbo that takes long to spool (I'll probably set the rev limiter to 6000-6500tops for longevity issues). Also, the heads will be the c5r 265ccs with a 72c chamber and flow 365@.600. Would a 91mmturbo be overkill for a 457ci street setup? I'm going for 850rwhp on the pump.
Here is an air map to a 427 LSX based motor.. http://www.forcedinductions.com/consumption427.htm At 6500rpm and it says you need 106lbs minute to suport 20psi.
I did the math and at 25psi it would be 120lbs minute. That's just air requirements.
RPM/PR would be 2.7.
A T88 with a P/R of 2.7 and 120lbs would be at 72% efficency. It is on the downward swing of the efficency range.
My guess would be with the added cubes a 88 would not be big enough and that a 91 or bigger would be needed to keep the turbo in it's efficient range.
I did the math and at 25psi it would be 120lbs minute. That's just air requirements.
RPM/PR would be 2.7.
A T88 with a P/R of 2.7 and 120lbs would be at 72% efficency. It is on the downward swing of the efficency range.
My guess would be with the added cubes a 88 would not be big enough and that a 91 or bigger would be needed to keep the turbo in it's efficient range.
