S15 piston compression ratio - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

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

, 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

Quote:

Originally Posted by fliprayzin240sx

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

Quote:

Originally Posted by Sileighty_85

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.

Quote:

Originally Posted by Ghost05

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.

01-11-2009, 01:51 AM	#1
tuketo Join Date: Feb 2008 Location: Las Vegas Age: 34 Posts: 26 Trader Rating: (0) Feedback Score: 0 reviews	S15 piston compression ratio 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

01-11-2009, 10:55 AM	#3
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	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. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

01-11-2009, 03:37 PM	#5
smelly240 Nissanaholic! Join Date: Oct 2006 Location: Philaburbia Age: 43 Posts: 2,137 Trader Rating: (4) Feedback Score: 4 reviews	s15 pistons have the coating on em. __________________ HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

01-12-2009, 03:37 AM	#9
smelly240 Nissanaholic! Join Date: Oct 2006 Location: Philaburbia Age: 43 Posts: 2,137 Trader Rating: (4) Feedback Score: 4 reviews	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. __________________ HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

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01-11-2009, 04:50 PM	#6
tuketo Join Date: Feb 2008 Location: Las Vegas Age: 34 Posts: 26 Trader Rating: (0) Feedback Score: 0 reviews	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

01-11-2009, 10:40 PM	#7
Ghost05 Join Date: Mar 2008 Location: Sacramento Age: 32 Posts: 24 Trader Rating: (0) Feedback Score: 0 reviews	the extra power in the S15 SR. can be attributed to simply a better tune (variable valve timing, boost etc.)