View Full Version : S15 piston compression ratio
tuketo
01-11-2009, 01:51 AM
what is the compression ratio for the S15. In the AU FSM it says 8.5 but I thought it was higher then that, is it just the AU S15's that get 8.5 or is there different versions.
I'm basically trying to get my SR rebuilt but with OEM parts and would like higher compression ratio if possible. no more then 9.5:1
Future240
01-11-2009, 02:26 AM
It might be the alcohol, but wanting to rebuild an engine with oem parts and wanting a higher compression seems like an oxymoron. This might be my newbness but I thought turbo motors did better with lower compression since higher compression leads to knock:confused:, ah shit i dont know....................
fliprayzin240sx
01-11-2009, 10:55 AM
Umm...all RWD SR20DET uses 8.5:1 compression pistons. The only thing im not sure about is if itsall the same pistons for all S-chassis.
Sileighty_85
01-11-2009, 11:09 AM
Umm...all RWD SR20DET uses 8.5:1 compression pistons. The only thing im not sure about is if itsall the same pistons for all S-chassis.
It is. Same displacement, Same bore, same stroke, same bottom Ends.
Minus a few small differnces.
smelly240
01-11-2009, 03:37 PM
s15 pistons have the coating on em.
tuketo
01-11-2009, 04:50 PM
I just thought that the S15 would be higher compression ratio, I read it somewhere but it must have been false statement I guess. It just seems like it because of the power they make compared to S14 SR extra 30hp
Ghost05
01-11-2009, 10:40 PM
the extra power in the S15 SR. can be attributed to simply a better tune (variable valve timing, boost etc.)
fliprayzin240sx
01-12-2009, 02:14 AM
It is. Same displacement, Same bore, same stroke, same bottom Ends.
Minus a few small differnces.
Only reason I said they might be different is because I'm pretty sure they are different parts numbers from Nissan. Atleast from what I remember from looking it up a long time ago.
the extra power in the S15 SR. can be attributed to simply a better tune (variable valve timing, boost etc.)
Most of its from the bigger, ballbearing turbo...
smelly240
01-12-2009, 03:37 AM
the NA s15 had rather high compression... the turbo ones all have the 8.5 pistons like every other RWD turbo sr - just with a thermal barrier coating.
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