hi

I did a compression test on my car today. I get 160 to 165 psi which still appears to be within spec but a little on the low side. I have read of other people getting over 200 psi! Is mine low? When I add oil to the cylinder, the compression goes up to 190. Worn rings I think!

 

Boosting 11.5 psi too much.............j/k

 

Did you do the test with the engine warm. This can drastically alter the readings from a cold engine and is far more accurate. If you did do it warm, I think you're right about the rings. If the compression rises during a wet test, either the rings or cylinder wall itself is worn.

 

Actually, I did it when it was cold. I don't like messing with it when it's hot! Yeah, I read the manual about doing it when warm but didn't think it would make a huge difference. I'll try it again when it is warm.

Thanks!

 

Did you do a compression test before you were boosted...?

 

I don't think I mentioned anything about turbo ... just asked if my compression was considered low

 

There's a chance that your guage reads low too. I've seen different guages read different things.

The important things (in my mind) are numbers in all six cylinders that are very close, and consistancy over a long range.

IE, if you got 160 before a mod and 160 after, then you have nothing to worry about. However, if by installing something (boost, nitrous, whatever) you go from 180 to 160, you've got problems.

 

I thought the same thing when I did a compression check on the old BMW I just bought. Cold, the readings were 150,135,145,125,120,120. Considering they are supposed to be between 142-154, these numbers scared me a little. I decided to do the check again after the car was warmed up. The numbers were now, 150,150,145,150,135,150. I'm much happier My guess is that you might see similar results.

 

HAve you a chance to do a retest yet?