i have a 99 si that i put a gsr in im new to the whole import scene i have quite a few bolt ons just had it tuned im only at 158 horsepower my best run is only a 15.1 and i did compression test today my compression ran between 100 and 110 on the cylinders does anyone know what the test numbers should be and what the problem could possibly be? please help!

 

Well, you are loosing a lot of compression. That motor has either bad rings, bad headgasket, or a bad head. You should be around 180-220psi.

 

dont get offended but did you do the test right (cranked it over enough), if so put a few squirts of oil in each cylinder, if the compression goes up then you need new rings, if the compression stayes the same check for compression leaks elsewhere, ex. valve seals

 

i did put a few squirts of oil in each cylinder and the compression did go up it jumped to between 130 and 160 i guess it just looks like i got screwed by the performance shop i bought it from they said they did a compression check on it and it appears they lied

 

The engine certainly wouldn't be putting down 158 whp if you were only pulling 100-120 psi per cylinder. Hell, I even doubt that it would run.

Obviously, the compression test was done wrong. Was the engine warm or cold? Where you cranking with the throttle plate all the way open? Was fuel injection disabled? How many times did you crank it?

 

i have never done a compression test before so i guess i did it wrong, the guy that told me how to do it just told me to unplug distributor and then start the test

 

hold throttle plate wide open disable injectors (just unplug them), unplug the distrib. and crank it like 6 turns, let us know how that turns out

 

i will thanks for the help guys

 

make sure the engine is up to operating temp, remove the ecu fuse, remove all plugs, hold the throttle wide open, and crank it at least 5 times.

btw, 158whp isnt bad. what mods do you have?

 

i redid the test i got 245 250 245 and 250, i have peak performance header, aem intake, peak performance intake manifold, walbro fuel pump, accel 310 cc injectors, bdl fuel rail, greddy exhaust, high flow cat, excedy stage 1 clutch, i just had it tuned and my dad seems to think it was a bad tune, im still running rich i just put new plugs in it the other day and they are already fouled up