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What would my compression be?

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Old 09-12-2013, 08:05 PM
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Default What would my compression be?

What would my compression be. Ive got a stock lq4 going with 220 tfs heads with 65cc and was looking at .40 head gasket. I know its 9.4 stock. Tried using online calculators but i just don't have all the correct info to make them work.
Old 09-12-2013, 08:32 PM
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There's a sticky on this somewhere but those chambers and gaskets seem to
have a total of about 10-11 cc less volume which makes me guess that you
are right about 10.65-10.70
Old 09-13-2013, 01:15 PM
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Originally Posted by A.R. Shale Targa
There's a sticky on this somewhere but those chambers and gaskets seem to
have a total of about 10-11 cc less volume which makes me guess that you
are right about 10.65-10.70
Id be happy with that cuz i really dont want to mill these heads rate now.
Old 09-13-2013, 01:22 PM
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Originally Posted by A.R. Shale Targa
There's a sticky on this somewhere but those chambers and gaskets seem to
have a total of about 10-11 cc less volume which makes me guess that you
are right about 10.65-10.70
Originally Posted by 68BBChevelle
Id be happy with that cuz i really dont want to mill these heads rate now.
Compression is free horsepower, so milling will net you a little more HP. If you have the PTV clearance, I'd do it in a heartbeat. I'm running Cometic .040's currently on my setup, with TSP LS6 2.5's that are stock chambered 64cc, so my CR is ~ 10.8-10.9. Looking back I wish I'd have milled my heads to 62cc chambers for a little more HP and torque.
Old 09-13-2013, 02:33 PM
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Originally Posted by 427zm
Compression is free horsepower, so milling will net you a little more HP. If you have the PTV clearance, I'd do it in a heartbeat. I'm running Cometic .040's currently on my setup, with TSP LS6 2.5's that are stock chambered 64cc, so my CR is ~ 10.8-10.9. Looking back I wish I'd have milled my heads to 62cc chambers for a little more HP and torque.
I know im leaving power on the table by not milling my heads. I just want meat left in case i have a boom in the future ill still have something there to play with instead of buying a new head. How much power am i really leaving out there?
Old 09-13-2013, 02:49 PM
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Originally Posted by 68BBChevelle
What would my compression be. Ive got a stock lq4 going with 220 tfs heads with 65cc and was looking at .40 head gasket. I know its 9.4 stock. Tried using online calculators but i just don't have all the correct info to make them work.
Bore: 4"
Stroke: 3.622"
Headgasket: 4.085" x .040"
Piston Deck Height: ~.005"
Chamber CC: 65cc
Piston CC: +8cc

Swept: 745.99cc
Head Gasket: 2.1cc
Deck: -1.03cc
Chamber: 65cc
Piston: +8cc

CR: 11.07:1
Old 09-13-2013, 08:16 PM
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Originally Posted by KCS
Bore: 4"
Stroke: 3.622"
Headgasket: 4.085" x .040"
Piston Deck Height: ~.005"
Chamber CC: 65cc
Piston CC: +8cc

Swept: 745.99cc
Head Gasket: 2.1cc
Deck: -1.03cc
Chamber: 65cc
Piston: +8cc

CR: 11.07:1
Thank u sir thats what i was after.
Old 09-13-2013, 10:07 PM
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Originally Posted by KCS
Bore: 4"
Stroke: 3.622"
Headgasket: 4.085" x .040"
Piston Deck Height: ~.005"
Chamber CC: 65cc
Piston CC: +8cc

Swept: 745.99cc
Head Gasket: 2.1cc*******never seen this before
Deck: -1.03cc
Chamber: 65cc
Piston: +8cc

CR: 11.07:1
also most forget to factor approx 1cc of primary ring volume
Old 09-13-2013, 10:41 PM
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Originally Posted by A.R. Shale Targa
also most forget to factor approx 1cc of primary ring volume
I don't even bother.



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