cylinder compression vs compression ratio
 

I did a compression check on my motor, it was 135 all across the board, hayne manual said 170 is normal and 110 is low, the stock piston have a cr of 9.0 with 70k mile on it.

My question is, can I calculate the correct cylinder compression with CR? is this formula correct? ===> 9.0 CR equal 9.0 x 14.7psi of atmosphere pressure that gives around 132psi?

The timing belt has not bein changed so the belt may off a tooth, which affects greatly on compression.

thanks alot.

Re: cylinder compression vs compression ratio
 

no...

Re: cylinder compression vs compression ratio
 

You need to factor in closing valves (basicly decreases displacement), volume below the HG, the volume the HG uses, the chamber size, and the volume 'added' by your compression tool. You probably also didn't open the throttle body, as leaving it closed makes a big difference.

Compression testers are really meant to compair one cylinder to another, not your numbers to a book number. They should all be w/in 5% of each other.

Re: cylinder compression vs compression ratio
 

throttle was wot when i did the test, i changed timing belt yesterday the cam was off a tooth, fixed it and redid the compression, is still same. however theres almost no variation betwen cylinders.

Re: cylinder compression vs compression ratio
 

the gauge is wrong VS you're fucked = you're fucked.