Compression ratio question

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Apr 25, 2014 | 01:15 AM

lsxnoobneedhelp

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Compression ratio question

LIKE MY NAME SAYS
The engine builder told me the compression ration will be 11:2:1 with the parts I'm using, but when I put in the info into a compression calculator, it comes out wrong

Its a lq9 bored to a 408 (4.03" bore/4.00" stroke)
-3cc wiseco flattop pistons
68cc ls3 aftermarket heads
.051" head gasket
and a lq9s deck clearance is 9.24

When I put all this into a compression calculator, it came out to be 1.42:1

Apr 25, 2014 | 01:40 AM

Werewolf SS

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Your builder is correct. Your combination would be a 11.2 : 1 .The calculator you used is either messed up or a value was incorrectly entered. I have the same setup except my pistons are -1.8cc and my headgasket is .041 and that gives me a 11.6 : 1 ratio.

Apr 25, 2014 | 01:42 AM

98TransAmWs-6

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You are doing something wrong then. I did the calculation and it comes out to 11.23:1.

Apr 25, 2014 | 02:06 AM

lsxnoobneedhelp

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What calculator are yall using

Apr 25, 2014 | 02:16 AM

Werewolf SS

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just type in compression calculator on google. Most use the first one but any of them should be fine. Deck height is only used to figure out if your piston is going to stick out of the hole any. No calculator will you actually put 9.24 for deck height. I think that might be what has messed you up.