Forced Induction Superchargers | Turbochargers | Intercoolers

ideal compresion?

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Old 12-30-2002, 08:59 PM
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Default ideal compresion?

i am going to be geting some forged pistons soon and am wondering if i should drop the compresion some? and if so how much.

stock is 9.4-1, i can only run 6-7psi now before detonation sets in. the blower has the capasity to run 10+psi on my current set up so if i droped the compresion i would be able to up the boost.

i have no intercooler and may hit it with some nitrous in the future if that makes any diference. 92 octane also.
Old 12-30-2002, 09:57 PM
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Default Re: ideal compresion?

after doing a search i see 9-1 is a common ratio so now my question is since i have a blower that makes instant boost at low rpm's would that change the acepted 9-1 ratio at all?

i am told lightings run 8.5-1, i will probably stick with the 9-1 unless someone on here thinks it should be less.
Old 12-31-2002, 04:03 PM
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Default Re: ideal compresion?

i chose 9.0:1 on my street/track car.
with the lower CR the more boost you can run, but loose throttle response and streetabilty, i think 9:1 is just right for a turbo car on the street, not to laggy but able to run some good boost.

for notes Y2K hawk (harlan) has his 700rwhp beast at 8.5:1 CR
and Cablebandit (Jerry) had his 580 rwhp beast at 8.9-8.7:1
Old 01-04-2003, 07:32 PM
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Default Re: ideal compresion?

I think 9:1 would be a fine choice. I think thats a good choice. Once you drop compression, you will lose a little boost. Meaning it will take a smaller pulley to maintain the same amount of boost you are currently running. Instead of seeing 6-7, you will probably see 5-6 with the existing pulley.

BTW - I like your idea of entering PE earlier.
Old 01-04-2003, 07:40 PM
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Default Re: ideal compresion?

Your case sounds more like tuning.. I know of several blower guys with 10.1:1 compression running 9#'s with no problems..
Old 01-04-2003, 07:42 PM
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Default Re: ideal compresion?

no intercooler may have something to do with it also but yes it needs to be tuned with a wideband



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