Cylinder compression for 8.5:1 CR?

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Apr 14, 2009 | 10:11 PM

xa007xa

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From: Chicago, IL

Cylinder compression for 8.5:1 CR?

What's the ideal range for 8.5:1 CR? I tested at 155-160 psi. Service manual says 150psi is minimum but thats for 10.5:1 CR.

Apr 15, 2009 | 11:18 PM

703xB

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Joined: Aug 2007

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From: Manassas, VA

For a 8.5:1 ratio, anywhere from 150-170psi should be fine. 155-160 sounds pretty well within spec to me.

May 13, 2009 | 11:43 PM

vettereddie

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Scikotics
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From: Patuxent River, MD

I would think this is just simple math.

10.5 * x = 150 psi
x = 14.28

So at 8.5, it would generate 122 psi.

BTW, atmospheric pressure is about 14.7 psi at sea level, that's probably why x is not 1.

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