Compression Test

[SDEWY5]

I did a compression test on my car today, i got 125psi across all cylinders..is this ok? shit or good? i just cranked it over off the sarter motor...

Any feedback will be appreciated! thanks

[foznice]

I'm not sure if 125psi is good or bad, but I have heard that consistency across the cylinders (as you have) is a good thing).. sorry I can't be of more help.

[Primordial]

Hmmm.. I dont think it's a fantastic result.

I got my RB25DET done when I bought my car (57,000km's) and I got 160 across five cylinders and 150 on the other.

Yeah I heard that it's consistency that is a good thing, but the higher the better I think?

The guy who tested it (Unique Auto Sport in Castle Hill) said that they have tested heaps of RB25's and mine was up there as one of the highest they'd seen. I have heard a lot of people testing down around 140, but never as low as 125.

I'm not sure what the implications of this are though. Sorry I cant be of much help either...

[R31Nismoid]

Tried the search button?

Would have given the answer right off the bat

http://www.skylinesaustralia.com/forums/in...&hl=compression

http://www.skylinesaustralia.com/forums/in...&hl=compression

http://www.skylinesaustralia.com/forums/in...&hl=compression

[SDEWY5]

i did actually..didnt give me anything..

[SDEWY5]

well, i dont know what to think right now, maybe i didnt do the comp test correctly...but its even across all cylinders to the lb, so i think its all good...the engine has been very well looked after, i just did it out of curiosity...try it again tomorrow, getting a rollcage fitted so maybe they'll point me in the right direction as what it is...

[The Mafia]

Got a mechanic to do mine - 168psi to 169psi accross all cylinders. 1996 Series II with 92,000 genuine kms on it.

[R31Nismoid]

i did actually..didnt give me anything..

read my post then, i used it for you

[RB30-POWER]

Engine hot/cold will effect readings and also cranking speed, connect a booster battery whilst testing for accurate results. And lastly make sure its a WOT when testing.

[GTAHH]

125 isn't perfect but still in the reasonable limits. It's good when all the cylinder have lost compression equally, but losing compression doesn't mean a real lot as it's turbo, the turbo's will always have less psi than a N/A engine. I don't own an RB25 though but this compression is good enough (not great) for a turbo engine

Cheers

[benl1981]

Maybe the gauge reads different or the technique. Basically if it doesnt use oil and doesn't blow smoke you should be pretty right. Not much you can do about it besides rebuild

[SDEWY5]

theres no smoke or oil used, the turbo seals are blown out but driving off boost it doesnt smoke at all, power is still fantastic...i have a feeling the low readings were because my battery is ratshit...like i mean..if you start it and stall the car, be prepared to push it..that and my throttle body was closed...

Looking at my spark plugs, theyre almost brand new still, no buildup of anything at all, engine overall seems to be running brilliantly. Must have been the way i did it...

BTW, sorry nismoid...i searched but i didnt get a straight answer to what i was looking for so i posted a new thread...my bad...

[copycutter]

I wouldn't have thought this is much for an rb25, but I have heard that an even spread across all the cylinders is more important.

My rb25det from a 97' s2 r33 has between 153-160 across all cylinders, being the lowest and highest from all readings.

125 sounds a little low, but if the others say its ok if it aint using oil and water etc, then i could be wrong. Possible try testing another one if you can, just for reference.