Good compression test

[TrAb]

Hey guys what are good compression numbers for a turbo buick? I am going to be checking my compression when i get home tonight and wanted to know what to look for. I know i did a cold test a while back when the car was down and it didnt have very high numbers, cant remember exactly what they were. Also should i just let the car warm up, then hook up the guage and bump the engine over a couple times or is there anything else i should do? Thanks

 

[azbob]

Warm engine, pull plugs, disconnect power to ecm to stop fuel flow,open throttle body wide and lock, test away.

 

[disco stu]

What bob said. I believe cranking comp on a stock engine was about 135 for me. As long as the numbers are consistant with each other.

 

[KL Mallender]

Look for consistant pressures from all cylinders, actual cranking pressures will be affected by many variables, "Factory stock" engines typically pushed 140-150 psi, retarded cam timing/longer duration/wide center aftermarket camshafts can lower numbers drastically. #125 psi should be considered minimum for good street manners, any lower and problems of slow power production arise but allow more "Boost" psi at same ignition points/octane levels. Good luck.

Kevin.

 

[TrAb]

Just test all of them execpt that damn one on the passanger back left. I cannot get to it and its to hot to play around in there for long. Anyways all the rest read the same numbers. Around 135+...

 

[TrAb]

So im guessing my compression is good, but i still feel like the car should be faster. Maybe i have been spoiled by my other cars :redface: , but i think it feels like a high 14 low 15 second car right now. What else could i look into. I was thinking valve springs but i was told that those do not make a much difference until in the higher RPM's and its doing fine there.

 

[TurboBuRick]

More power can be had by upping boost-timing. You just need to make sure you have propper fueling. (pressure & octane)

What boost-timing-fuel are you running now?

 

[TrAb]

Boost is around 16lbs, timing i have no clue , fuel is 93 octane..

How would i adjust the timing???

 

[bmackinnon]

Boost is around 16lbs, timing i have no clue , fuel is 93 octane..

How would i adjust the timing???

Thru the TT chip.... but watch out for knock... what are the wot scan tool numbers looking like? O2? KR? AF? TPS? You DO have a scan tool, right???

 

[TrAb]

Thru the TT chip.... but watch out for knock... what are the wot scan tool numbers looking like? O2? KR? AF? TPS? You DO have a scan tool, right???

Yes i have a scan tool but im not to great with it. I think the 02's are around 750 or so at WOT, other then that i have only been watching for timing retard and when some popped up i just bumped the FP regulator a couple notches and it went away. Thats all i have done so far.