low compression pistons??
02-09-2007, 01:18 PM
#51
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ok so do i raise or lower compression here guys ???? usin stock pistons and the dealer is prob goin to resleeve and drop a new piston in..... so that will get the block back to normal.... as for the head wise, if i can raise compression ill mill the head and get a set of cams for him........lowerin the compression then ill use a thicker gasket cause there isnt much ya can do....
02-09-2007, 02:08 PM
#53
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my buddy isnt twinchargin anythin lol ok so raisin comp. will work then..... sweet..... whats a safe milling thousanths on the head, how much "meat" is there should i say, i milled my head .060 and the max was .070, raised my compression from 9.4 to 10.4/1...... but thats a ford....
04-05-2007, 11:24 AM
#54
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sorry to bring the thread back from the dead. I am in the market with new pistons which ratio would be optimal being that i have a ported sc with a 2.6 on it and possible 2.5 down the road..... keep in mind I have the 2.2L cometic headgasket
04-05-2007, 02:08 PM
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Also, I'd go with the Diamond Pistons and increase compression to 10.0:1 if your gonna stick with the stock blower.
04-05-2007, 02:20 PM
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If you got the 2.2 Gasket, that will probably lower your comp by about .5. So if you want 10:1, buy the 10.5:1 pistons. That should be perfect if you plan to keep the eaton. No reason to go that low with just the eaton.
04-05-2007, 03:18 PM
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ignorant.. no.. upping compression is ignorant just to gain a few hps when there are much BETTER and SAFER ways.. there is a reason you see FI cars in the 8 - 9 range and not 10+... and if a person is going to the extent of re-pistoning.. i dont see them staying with a stock FI setup 
04-05-2007, 03:49 PM
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ignorant.. no.. upping compression is ignorant just to gain a few hps when there are much BETTER and SAFER ways.. there is a reason you see FI cars in the 8 - 9 range and not 10+... and if a person is going to the extent of re-pistoning.. i dont see them staying with a stock FI setup
04-05-2007, 03:59 PM
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Really? I wouldn't go telling GM then. They for some reason think that making 1400hp on an 2.1L ecotec boosting 35psi is fine with 10.8:1 compression pistons. It's funny even GM tells you to up compression when using the stock eaton to 10.0:1 on the LSJ engine. But hey I guess you know more than GM so thats cool.
but to each his own...
04-05-2007, 04:18 PM
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your taking advice from people that dont really give to ***** about their cars because they have the ability to pay and play.. they go for wins.. want to be #1... i go for give me just as much power and be safe.. sorry but im not backed by a billions dollar company that can blow **** up left and right all day long and not affect the bottom line
but to each his own...
but to each his own...
They haven't rebuilt that engine design, which is being run in tons of drag cars in over 400 runs.
Forget it...
Hey I heard some guy put a BOV on his cobalt you should check it out.
04-05-2007, 05:09 PM
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04-05-2007, 05:12 PM
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Yes, but only if you have the capability to (bigger or more efficient supercharger or turbocharger). You reach a point where the stock supercharger takes more parasitic power to spin it than the power it creates, and this can be accomplished with stock compression ratio. Imma hafta agree with Alpha and say if you stick with the M62, keep or slightly increase compression ratio.
04-05-2007, 05:20 PM
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Yes, but only if you have the capability to (bigger or more efficient supercharger or turbocharger). You reach a point where the stock supercharger takes more parasitic power to spin it than the power it creates, and this can be accomplished with stock compression ratio. Imma hafta agree with Alpha and say if you stick with the M62, keep or slightly increase compression ratio.
04-05-2007, 05:27 PM
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I really wouldn't worry about it. I got bored one day and used one of those online horsepower compression ratio calculators (its accuracy is a good of a guess as mine) to see what it thinks the differences are in compression ratio X power. If I remember right, bumping it up a whole point only equated to about a 3% increase in power, so lowering it by half a point can't do too much harm I wouldn't think.
If you want an awesome mod, send your cams to Crower for a regrind. Someone here has a thread on it, 150 bucks and 2 week turn around time.
If you want an awesome mod, send your cams to Crower for a regrind. Someone here has a thread on it, 150 bucks and 2 week turn around time.
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