What Is Normal/good Compression For An Rb20det?

[esprit]

Hey all,

Couldn't find the answer from searching.

What is good compression for a healthy RB20DET engine? A car I'm looking at buying was apparently tested at 150 +/- 4 on all cylinders, is this a good reading? If not what should it be etc etc.

Advice appreciated

Cheers

[ToF]

Well from the manual the limit value is 128psi +/- 14 so for a motor that old I'd say its pretty healthy.

My RB20s comp is around 130.

[esprit]

Thanks. Anyone else?

[Drift R]

Yeah thats good, but are you sure they're not tellling fibs?

[gt-t_r34]

when i got my car i got a check done on it a i had 150 and all 6 and he said that was really good soo yeah it sound pretty healthy to me. mines still going hard!

[esprit]

Is a compression of 140 on all cylinders good also?

[GTRsean]

with an 8.5 to 1 comp ratio and what the manual says, that's pretty good.

warm eng avg should be 161 PSI , limit 128 PSI with no more than 14 PSI difference between cylinders.

[dezz]

when i was looking at getting a 33 locally, i asked some people in the know what compressions were good

they said 170 is perfect (this is RB25DET obviously)

and anything above 140 is still ok...anything like 130-135 or under, and its getting close to rebuild time...

just thought id let you know so you have a rough idea...

they also told me that consistency across all 6 is important as well

[esprit]

Hmm, assuming the "perfect" values for RB25 and RB20 are different yes?

[dezz]

id say so going by what people have said so far in this thread...

im just going by what i was told by someone who knows their stuff on here...

try PM'ing Merli...