Chip a 160k miles with 120 psi compression?
 

Alright so the title pretty much sums it up. Should I chip (I posted on that ST thread, but Im leaning more towards GIAC), a 99 1.8 with 160,xxx and 120psi compression (all the cylinders were within 1-2 psi of one another), turbo is still stock (not a big deal if it blows), clutch has been replaced previously.

I say yes.

Alright good good what is everyone elses vote. I don't consume any oil either btw.

Chip. Do it. Go with GIAC, REVO, or Unitronic. I've heard that the ST chip was hit and miss for 1.8T's but pretty reliable for 2.8's.

That is a very low compression seeing that a good stock 1.8t motor will have a reading around 185psi. I would try doing another compression test with another gauge just to make sure those readings are right.

120psi readings give you a 8:1 CR.

Yeah I was waiting for someone to say that would be a problem... If i remember right i did try my neighbors too and it said about the same, but its been a while now maybe I should try a different one. I always heard what was most serious was for the numbers to vary alot from one another, but being low cant be so good either.

Yeah I just looked up compression and stuff, 120 sounds really low, but I dont get whats causing it to be so low, the engine runs great, and I dont consume oil or anything like that... And the fact they are so low and even is weird too I couldnt find anyone with a similar case like that online..

Well adjusted altitude will effect the readings, higher altitude will have a lower reading.

Even numbers from all 4 just means they are dropping at the same right. You might want to do a leak down test, that will really tell you if you need to do some work on the car before you start doing mods.

Well I dont live in the mountains or anything... Im having trouble figuring out how the leakdown test works, how do I know if the cylinder Im testing is at TDC, the writeups ive seen say you need to do that. And, lets say the leakdown test isnt too bad, then what would that mean, a low compression test and an ok leakdown, or am I expecting the leakdown to be fairly bad since I did poorly on the compression test?

Well all the valves in that cylinder just have to be fully closed when doing the test and they will in fact be closed when the piston is all the way up.