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Discussion Starter #1
I've a 1997 v4 wrx none runner at the moment it's a work in progress I need to no what reading should each cylinder be is some any advice would be great guys thanks regards Nathan
 

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Black 2001 RS
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787 Posts
Depends on your compression ratio and elevation.

At sea level, atmospheric pressure is around 14.7 psi. If your engine is 10:1, I would expect compression readings around 147 psi.

If your engine is 8.5:1, I would expect 14.7*8.5 = 125 psi

At higher elevations, air pressure is lower, so you would get lower compression readings.

Denver is around 12 psi air pressure, so my RS at 10:1 would read around 120 psi.
 

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'96 OBS
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I'll just add that generally the important thing is that all 4 cylinders are relatively close in compression.
 

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2001 Impreza 2.5RS+T 2001 Legacy GT
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10% from the highest to lowest.

For the record, my motor which is a 257 bottom, 257 HG, and 251 heads are said to be around 8.5:1. I'm at sea level and I just recorded between 125 and 135 on my motor.
 
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