well, ive had my Z with my turbonetics kit on now for over 25k miles and i thought i would get a compresison/leak down test. To sum it real quick, 2 out of the 6 cyclinders had a 3% difference (2 had 7% and 4 had 10%). And all the leaks were pass the rings. just checking with you guys to compare numbers on your turbo Z's. thanks

 

My stock motor was 185-195 across the board IIRC...

 

I could run a chk out of curiousity but what ur running is fine and Alberto, if ur running 185-95 on compression ur doing Great, They should stay withing 10 or so % ideally

 

Are you talking about a leakdown percentage? If so, I would be concerned with anything near 10% or more leakdown. Most factory engines will leak down at less than 3% across the board.

 

sharif, you mean 10% between cylinder difference? some of my cyliners were at 3% and some hit 10%

 

With a basic compression check, you look for consistency between the cylinders, and hopefully you see less than 12-15psi variations between the holes.

But for a leakdown test, we dont compare...we look at the leakdown percentage individually. Anything more than 10% is concerning, as stock engines usually likedown at about 1-3%. They are very tight.

For instance..if you had 2%, 2%, 3%, 3%, 1%, 11%, this would indicate an issue with the last cylinder. The difference between cylinders, in this case, is irrelevant.

a 10% leakdown isnt the end of the world, it just means that cylinder is a little bit tired, and you might want to start saving up for an engine build.

 

10 % on compression not leakdown ---I really dont know what +- it should be ----U say 3 % Sharif ?

 

U were typing the same time I was ---Thanks, thats what I was asking