d16y8turbo

I tested my compression on my 97 d16y8 with 158xxx miles. I got 155, 150, 150, 150

these are within the range that I have heard is ok for my engine i just wanted to double check. Are these readings okay for boost?

phresh_5

Yeah those #'s sounds fine. It really isn't about how high they are, its about how much difference there is between the numbers. By looking at yours, I'd say your engines fine. A 15-20psi difference between cylinders is when you need to worry.

d16tuner

Lots of questions on this same topic.

Why is it that 20 psi is too much? I had a difference of 20psi between #1 and #4. #2 and #3 were equal (and in the middle between the other two). The compression goes from 175-195 which isn't low at all. I'm guessing the 150psi above is due to worn rings, right? What would cause the compression to rise 10psi in one chamber on my car? Carbon? Is 175, 185, 185, 195 not safe to boost?

d16y8turbo

I was under the impression that 150 was a decent, if not good reading?

-Aidan

d16tuner

I'm not saying it isn't ok to boost. I'm just saying it is lower then the stock compression *should* be. I'm certainly no compression expert - hence the questions.

TinyTurbo

as long as all your compression numbers are the same or close. I think the service limits are like almost 20. Check your service manual the compression is in their. Also are you holding it a wide open throttle when testing that is what you are suppose to do,it can increase it be 15 to 20 psi. D16tuner i would say your compression is high because of carbon.

racinskittle

compression of about 135-137 accross is TOO LOW.

Compression of 180 accross is NOMINAL.

Your results will vary with each compression test. Your numbers are fine still.

I can't remember the range but D16y8, you're numbers a definately close enough.