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help with compression

Old Oct 15, 2006 | 10:55 PM
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Ok, I have a set of heads that are going on my car. they are milled to 60cc's. I run a G5x3 on a 112 and would like to get the most out of it. I would like to run pump gas in my car unless it gets really hot out. I am stuck on what sort of gasket I should use to optimize compression, quench, and detonation. any help is great! also what is the norm for max compression street motors?

Last edited by yak; Oct 16, 2006 at 07:46 PM.
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Old Oct 16, 2006 | 10:11 AM
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anyone, patrick G or predator z have any input?
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Old Oct 16, 2006 | 08:38 PM
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The tighter the quench, the better your motor will resist detonation. As long as you don't run into any piston to valve clearance issues, I'd recommend going with a Cometic .040" head gasket. It's what I run. No problems with 93 octane for me! 30 degrees of timing and a DCR of 8.73:1!
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Old Oct 16, 2006 | 08:46 PM
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patrick, I just ran a quick compression calculator and got 12.1 scr and 9.21 dcr does this seem right? I think you know more about my cam than I do.
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Old Oct 16, 2006 | 08:51 PM
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Originally Posted by Patrick G
The tighter the quench, the better your motor will resist detonation. As long as you don't run into any piston to valve clearance issues, I'd recommend going with a Cometic .040" head gasket. It's what I run. No problems with 93 octane for me! 30 degrees of timing and a DCR of 8.73:1!
So what is your quench spec and what are the limits for a street car or a weekend warrior? I have heard some say .035 for a street car is as tight as you should go, others say .030-I guess it depends on application. Sorry to jack the thread
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Old Oct 16, 2006 | 08:57 PM
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Originally Posted by Dave88z
So what is your quench spec and what are the limits for a street car or a weekend warrior? I have heard some say .035 for a street car is as tight as you should go, others say .030-I guess it depends on application. Sorry to jack the thread
well stock pistons come .007 out of the hole so with a .040 gasket i would have a quench of .033 right?
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Old Oct 21, 2006 | 05:31 PM
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Correct.
Are your piston flycut? you need valve reliefs to run that cam with 60cc head
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Old Oct 21, 2006 | 08:10 PM
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the pistons are not notched yet, but I am aware that I will need to flycut.
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Old Oct 22, 2006 | 03:35 AM
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Good, then you can run a nice tight set of Cometics .040
Shoot for 11.35 SCR, if your cam is a 112+4 you'll be in the 8.6 DCR territory and you would have optimized your combo.

I think 2 cc reliefs might do it (not sure though)
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