Forged 383 FI Piston questions
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Forged 383 FI Piston questions
Hey guys, I have a 99 LS1 I got that came out of a vette with only 28,000 miles. I cleaned it up painted about everything and was getting ready to put it into my V6 Firebird, when I got the itch to do FI. I am looking at a Vortech Supercharger by the end of next summer. But I don't wanna slap a supercharger on there and only be able to put a lil boost on it, I wanna put around 12psi. So I have since decided to go ahead and do a forged 383 to be able to handle this and be reliable in the future. But I need to know what pistons to get. I know for forced induction you want lower compression to be able to use pump gas safely, but how low? Plus my supercharger won't be on for another year almost. Will the car be slow as hell till then if I put dished pistons? Please let me know if there is anything else you would reccommend. And also keep in mind I am a college student and want to keep this as budget as I can.
So should I go dished or flat top? If so how many -cc's?
Here's some pics of the engine a few weeks ago, now its got the FRC and F-Body Oil Pan...
- Callies Compstar Forged Crankshaft 4.00"
- Callies Compstar H-Beam Connecting Rods 6.125"
- Diamond Pistons -15cc?
- Futural F7 Camshaft
- PRC LS6 Ported Heads (Not till around April)
- Patriot Gold Double Spring Kit
- TSP pushrods
So should I go dished or flat top? If so how many -cc's?
Here's some pics of the engine a few weeks ago, now its got the FRC and F-Body Oil Pan...
Last edited by pemberton; 09-29-2010 at 01:34 AM.
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There are only so many shelf pistons available.
Find out the head cc
Head gasket cc
piston deck height.
Check out one of the many CR calculators on the net.
Slow - depends on the cam and CR.
Find out the head cc
Head gasket cc
piston deck height.
Check out one of the many CR calculators on the net.
Slow - depends on the cam and CR.
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Thanks! Yeah I'm gonna go with some -8cc I believe. What headgasket are you guys running that will be good for a 600 hp supercharger? I'm trying to get some numbers for compression ratio....
Last edited by pemberton; 09-27-2010 at 03:16 PM.
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Yeah I was gonna go with a .045". Is there any pros and cons to using a thicker gasket than a thinner one. Besides compression ration I would think the thicker ones would hold better...
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Funny I came out with 9.525:1 with a 3.903" bore, 4" stroke, gasket diameter of 3.910 thickness of .045, head combustion chamber of 72cc, piston dome of -8cc, and clearance of .016. Used this calculator to get it:
http://www.csgnetwork.com/compcalc.html
http://www.csgnetwork.com/compcalc.html
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I'm building a 383 as well. I'm using CP forged bullet pistons with -18.2cc's, heads with 62cc chambers and a GM MLS gasket of .058" for a compression ratio of 9.6:1 (perfect ratio for a blown LS). I've thought long and hard about it and after exhaustive reading came up with this setup. I'm running a Magnacharger but it should work great with a Procharger or anything else. Oh, and the price is right. As a bonus, the guys at Campbell Performance are FIRST class.
Last edited by swift700; 09-27-2010 at 05:52 PM.
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Well with a 64cc combustion chamber and a -18cc that puts me at 9.34:1. I'd like to be around 9.5:1. Is there a head you guys would recommend with the larger cubes. SOMbitch touched on it with the 317 heads. But what heads will flow the best for a procharger? I just wanna flood the sombitch with air and gas!!! Then I'll be buying a new rear-end though.
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swift are you sure you calculated that compression ratio right? I got 9.28 using this:
http://www.csgnetwork.com/compcalc.html
Using a bore of 3.903", stroke of 4", gasket bore diameter 3.910...
http://www.csgnetwork.com/compcalc.html
Using a bore of 3.903", stroke of 4", gasket bore diameter 3.910...