Need some help on why car is falling on its face, dyno included.
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#10
So you think it might be too small of a turbo? The install shop said at 16 psi it was like 3 to 1 back pressure but didn't know why. Maybe the turbo b is too small causing all of this. Hmmm
#11
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I have a PT7675 that is probably the same size as your turbo on a 6.0. I have LS3 heads but I went from a 220/220 cam to a 224/230 cam and it seems to run a little worse up top, I suspect its back pressure related. I feel like a turbo this size would work better with a small cam like an LS6 but I could be wrong, all speculumation!
#12
I have a PT7675 that is probably the same size as your turbo on a 6.0. I have LS3 heads but I went from a 220/220 cam to a 224/230 cam and it seems to run a little worse up top, I suspect its back pressure related. I feel like a turbo this size would work better with a small cam like an LS6 but I could be wrong, all speculumation!
#13
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And look at Stock48s truck, at one point he had a BW S400 with the same size turbine I think on his 6.0 truck and he made a lot of power/went really fast at a lot of weight, so it might not be completely turbine related. He does run a smaller cam in his stuff to so that might be part of where I am getting my small cam theory for small turbines.
Strange the shop was surprised by 3:1 bp on a tiny turbine on a 383. That shouldn't surprise anyone really.
Confirm its really a 75mm turbine, but .96 kind of points to that.
And its not like its running particularly bad, just doesn't peak very high. We are pretty fickle these days about power....."why am I only making 630whp??" You'd never have heard that 10 years ago
Strange the shop was surprised by 3:1 bp on a tiny turbine on a 383. That shouldn't surprise anyone really.
Confirm its really a 75mm turbine, but .96 kind of points to that.
And its not like its running particularly bad, just doesn't peak very high. We are pretty fickle these days about power....."why am I only making 630whp??" You'd never have heard that 10 years ago
Last edited by Hank Peabody; 11-20-2014 at 10:07 PM. Reason: added the word "bad"
#20
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Look at dyno graphs for LS1 and 76gts on google and most graphs look like yours. Mine does too. Still runs great but doesn't peak very high on the dyno, nothing wrong with the setup unless you just want more.