Compression #'s on a rebuild, good or bad

[a1320eclipse]

The head was completely gone through about 3500 ago. about 1500 miles ago i re-ringed and honed the bottom end because i was stupid and didnt listen for detonation while running 15psi, hence pistons 3 and 4 took a crap. before the build, my compression numbers were 145-150-145-90. So ive got about 1600 or so miles on it and just tested it again and my numbers are as follows: 150-150-145-155. i was reading through here and most guys on a rebuild were gettin numbers up in the 165-170 range, should i expect those kinds of readings or will they come up more with a little more time. the head is of a 93 gs-t, so i dont know if the head off the 7 bolt will yield the same compression numbers. any insight would be helpful. the car runs very well. actualy, with a boost controller, filter, and open dp, it ran a 13.28@102.

 

[alex]

For a 1g, the compression with a fresh new rebuild should be 164 PSI according to the manual. You should never have anything greater than a 14-16 PSI difference.

 

[gurmanator]

if anything your numbers will go down but thoes are good numbers.

 

[keymaster]

Why do you say the numbers will go down??? As the rings seat the compression should go UP. That is, unless you don't break it in properly and they never seated correctly, in which case you'll never get full compression without re-ringing and re-honing the cylinders.

 

[DSMedEG]

geez what i wouldnt do for 150's across the board, shoot driving around with 110's is fun.

 

[fanatic26]

T i was stupid and didnt listen for detonation while running 15psi, hence pistons 3 and 4 took a crap.

With compression as low as these motors have, how could you blow the motor with a stock turbo at 15 psi? There is enough injector to handle it and the knock sensor should have told the ECM to pull timing when needed. Is there something more i need to know about these motors before I modify mine?

 

[a1320eclipse]

nope, it was my bad, i accidentaly turned up the boost controller to 24psi on accident on a tired bottom end, so the ring lands on 3 and 4 went south. im back on 15 psi with a fresh rebuild on the bottom end and it runs very strong. if you maintain these cars they can be reliable.