low compression numbers?

[GSX JOE]

well took my bro's 92 gsx to get a compression test done and i was kinda surprised by the numbers. The car runs strong and boosts very nicely. Well the numbers were 105,105,105, & 115. Now if the numbers were that low wouldnt there be some kind of symptoms? Like smoke, running poorly etc.? Plus all 4 were within 14psi.

Im wondering if the shop didnt do the test correctly? Maybe didnt warm up the car or something else stupid. It was a real hole in the wall place. Well im gonna do my own comp. test and leakdown this week and see what i get but i was just curious if anyone had any thoughts, thanks

 

[DSM91]

Make sure the throttle is wide open (flooring the gas pedal) and make sure the engine is up to operating temperatures.

 

[ASZRAEL1266]

When did mine i got 150 150 151 150. I know this is going to sound dumb but what is a leak down test? Is it a boost leak test done a diffrent way or somthing?

 

[92redman]

The minimum compression is 120psi. You may or might not see any symptoms depending on why the compression is that low. Or like DSM91 said, the throttle might not have been open all of the way. The leak down is done by bringing the cylinder to top dead center and feeding compressed air into the cylinder. The equipment gives a % of pressure leaking and you also can listen to hear if the air is escaping passed the valves.

 

[GSX JOE]

thanks everyone for there imput, i did my own test tonight and got 110,110,110, and 115. Still a little low, still bothers me that the car runs so good but has this low of compression. Well i guess i will be doing the leak down test soon.