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Compression Ratio Calculation

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Old Mar 23, 2009 | 06:26 PM
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Default Compression Ratio Calculation

Does anyone have a formula to calculate static compression ratios for assembled engines? I figure X= bottom end compression and Y= top end compression, so X + Y = Total static compression????? or is it X(Y)/2?

I'm asking because in the next year or so I'll be starting my FI build, and I'm in the planning phase now and I want to make sure my numbers are right. The Lunati 395 Stroker Kit seems to be the direction I'm going in. The kit is offered in 3 different compressions :

8.7:1
10.4:1
12.2:1

In my mind, the 10.4:1 would be the wiser choice to use with say and LS head with these specs:

Combustion Chamber: 72cc
Intake Runner: 227cc
Exhaust Runner: 70cc
Intake Valve: 2.055"
Exhaust Valve: 1.57"
(Patriot Performance LQ9 Stage II)

Which advertise a drop from 10.1:1 to 9.0:1 on a stock LS1. So if X(Y)= Z, am I looking at a 9.5:1 compression?

I don't mean to seem like a bother, but I love this FI section, it's physics class all over again!!!!!!!!!
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Old Mar 23, 2009 | 10:59 PM
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any body?
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