Rb25 Det Compression Results

[Nii San]

Hi guys i know this has been talked about on here before but needed some specific questions answered.

im looking at buying a r33gtst s2 with (as far as i know stock internals).

i arranged for a mechanic to compression test the motor with the results

CYL1 150PSI

CYL2 150

CYL3 140

CYL4 145

CYL5 150

CYL6 145

I wasnt actually able to be there when it was performed (work commitments) but when i asked if the test had been done cold or hot, the mechanic said cold

and that this was normal to do it cold and that the motors compression was fine.

having looked on here i can see most guys say to do it hot...

so my questions are

1. will the compression likely be higher when tested hot.

2. if tested cold can this hide potential problems with the motor.

3. what is an acceptable tolerance between cylinders (have seen conflicting info).

thanks for any info provide

Regards Will

[Kenna802]

less than 10 percent is a good result and afaik hot results usually give better compression

[LANDSCRIBBLE]

those results are pretty much identical to mine

[boostn0199]

Seems like a pretty healthy engine id be happy with that.

[Nii San]

ok thanks for advice guys very happy with everything else on car so this might be the one

[Trozzle]

lol yeah those results are awesome, mine are ~130psi rofl

[PewPew]

With compression tests consistency between cylinders is usually more important than outright numbers, unless they're something ridiculous 90 on all cylinders. From the results you've given, it looks like a healthy RB25

[dori34]

as long as they're within 5-10psi from each other, thats the important thing.

any more variances will indiciate an unhealthy engine.

[AngryRB]

i wouldn't settle for "if its within 5-10psi of each other then its good"

id want minimum 160psi for each cylinder hot or warm, 140-150 is like 8:1compression ratio so lazy and worn out a bit... why settle unless thats what you have and have to work with it..

mine is 160 000kms old and still has 170+/-5psi, so a perfect condition motor is probably about 180psi each cylinder, i stand to be corrected.

[Nii San]

Thanks for all input fella's i now have a better picture of what to look for and what im after. i wasnt really happy with car after test drive so didnt end up buying it anyway

[Mayuri Krab]

less than 10 percent is a good result and afaik hot results usually give better compression

Is that between the highest & lowest reading cyl or when compared to the average/majority reading?

I got one at 155 (cyl 1), one at 165 (cyl 5), rest all @ 160

[Captain Natro]

for an NA Engine should comp test psi's be higher? please pm answer.

[defari]

Thanks for all input fella's i now have a better picture of what to look for and what im after. i wasnt really happy with car after test drive so didnt end up buying it anyway

Shouldnt you have test drove the car before getting a compression test?