fyi, wiseco does not make a 9.0:1 piston
11-16-2007, 03:56 PM
#81
Tour de Franzia
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Hustler-read. http://www.musclemustangfastfords.co...tio/index.html
Using the 4% rule. Assuming you make 250whp with 9.0:1 ratio pistons.
9.0-8.6=0.4 This is the change in compression
.4 X 4%= .016 This is how much power will change.
1-.016= .984 This is your new power factor.
250whp X .984= 246whp with 8.6:1 compression. That's a 4WHP difference, which would be almost undetectable.
Using the 4% rule. Assuming you make 250whp with 9.0:1 ratio pistons.
9.0-8.6=0.4 This is the change in compression
.4 X 4%= .016 This is how much power will change.
1-.016= .984 This is your new power factor.
250whp X .984= 246whp with 8.6:1 compression. That's a 4WHP difference, which would be almost undetectable.
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11-16-2007, 04:02 PM
#83
And they will be linear. If you increase power X%, your spool RPM will drop X%. Do you understand these are related? That's the whole point of me doing that math is to show you that 1.6% change in power or spool isn't gonna make a ****. Hence, you should have kept the pistons you had.
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11-16-2007, 04:12 PM
#88
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Maybe he should wait the 3 weeks get some nice custom 9.5:1's or 10:1's. Then his only trouble is the turbo he has may be a bit excessive. This may not effect spool but the car will be snappy off boost. You could also send out the head and get it ported. Between the two you would definitely have what you want.
+1 on the FM idea
+1 on the FM idea
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11-16-2007, 04:27 PM
#93
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Not directly comparable, but my stock motored 94 (8.8-1) running a standard FMII (GT25) made 15 psi by 3100 rpm. 12 psi by 2900. I dropped from 3400 by spending some time on the dyno. Car has no cat, and a 3" exhaust. Compression ratio is a minor detail. Open exhaust and a good tune are much more important and make a much bigger impact on how the turbo will spool.
Any turbo car will feel like a dog off boost. Its because on boost is so much more fun. I can tell you that I RARELY experienced lag in my car. And that was usually a result of me being in the wrong gear.
Any turbo car will feel like a dog off boost. Its because on boost is so much more fun. I can tell you that I RARELY experienced lag in my car. And that was usually a result of me being in the wrong gear.
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11-16-2007, 04:31 PM
#94
Boost Czar
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When I drove around with my wastegate wired open I thought the car was broke. I was actually scared to take it WOT cause it just wasn't right....even though I knew in my mind I just lost 250% of the power on purpose.
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