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Lowering CR for turbo LQ9 with 317 heads

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Old 03-23-2017, 11:04 AM
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Default Lowering CR for turbo LQ9 with 317 heads
I would like to know if the 317 heads can be opened up to bring the CR down to 9-9.5:1 on an LQ9 for a turbo app.
Any ideas/comments appreciated !
Thanks
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Old 03-23-2017, 12:38 PM
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Simple answer is YES. What fuel are you going to be running?
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Old 03-23-2017, 01:18 PM
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Originally Posted by gnx7
Simple answer is YES. What fuel are you going to be running?
94 octane and meth, no E85 around here
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Old 03-23-2017, 01:42 PM
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Cometic makes a .060" head gasket which I'm thinking is .009" thicker than the factory LS2 or LS9 gaskets and should get it down to about 9.75:1
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Old 03-23-2017, 01:46 PM
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Originally Posted by A.R. Shale Targa
Cometic makes a .060" head gasket which I'm thinking is .009" thicker than the factory LS2 or LS9 gaskets and should get it down to about 9.75:1
I was thinking of a thicker HG too, but some say it's a bad idea...would run about 15-16 PSI boost...an LQ4 would be ideal, but.....
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Old 03-23-2017, 02:05 PM
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Originally Posted by richincanada
I was thinking of a thicker HG too, but some say it's a bad idea...would run about 15-16 PSI boost...an LQ4 would be ideal, but.....
NA engines are quench sensitive, boost and NOS engines (from my experience)
just don't give a crap how close the piston is to the head
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