Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Go Back   Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum > General > Tech Talk > Engine Tech

Engine Tech Technical discussion related to all relevant engines such as KA, SR, RB, CA, 2JZ , L24/26/28, VG, VQ, and LSx series.


Reply
 
Thread Tools Display Modes
Old 02-01-2017, 02:24 PM   #1
gaz_moose
Zilvia Member
 
Join Date: Mar 2008
Location: engerland
Posts: 242
Trader Rating: (0)
gaz_moose is an unknown quantity at this point
Feedback Score: 0 reviews
SR20 from 8:5:1 to 9:1 compression

Ive changed from stock compression ratio to roughly 9:1, am I going to be ok using the car on the current map that I had done for the old compression ratio? I want to put some miles on it before I stick a bigger turbo on it and go all out on the rollers. I don't plan on bashing it off the limiter just cruising it around on the 100RON fuel its mapped for..

its a VVT s14 engine mapped on nistune with s15 injectors and turbo/z32afm,

it had decent (140psi) compression test results when mapped and should have 150/160 across the board now as its brand spanking new.

soo. id going up half a point on CR a real deal breaker??
gaz_moose is offline   Reply With Quote
Sponsored Links
Old 02-01-2017, 05:58 PM   #2
hanzbrady
Zilvia FREAK!
 
hanzbrady's Avatar
 
Join Date: Apr 2015
Location: Floriduh
Posts: 1,168
Trader Rating: (4)
hanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura about
Feedback Score: 4 reviews
You could be fine, you could melt a piston.

Or, you could tune the car and know it's safe.
__________________
[email protected]
hanzbrady is offline   Reply With Quote
Old 02-02-2017, 07:40 AM   #3
gaz_moose
Zilvia Member
 
Join Date: Mar 2008
Location: engerland
Posts: 242
Trader Rating: (0)
gaz_moose is an unknown quantity at this point
Feedback Score: 0 reviews
money..it all boils down to money.

tune the car on current setup cost money..which could go towards eventual goals..

buy new turbo cost money..

retune to suit new turbo even more money..
gaz_moose is offline   Reply With Quote
Old 02-02-2017, 07:41 AM   #4
hanzbrady
Zilvia FREAK!
 
hanzbrady's Avatar
 
Join Date: Apr 2015
Location: Floriduh
Posts: 1,168
Trader Rating: (4)
hanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura abouthanzbrady has a spectacular aura about
Feedback Score: 4 reviews
Rebuilding engines cost more money.
__________________
[email protected]
hanzbrady is offline   Reply With Quote
Old 02-02-2017, 07:57 AM   #5
TheRealSy90
Premium Member
 
TheRealSy90's Avatar
 
Join Date: Mar 2009
Location: Maricopa, AZ
Age: 30
Posts: 7,679
Trader Rating: (10)
TheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant future
Feedback Score: 10 reviews
150/160 with 9:1 pistons? My stock unopened s13 sr will do 180 on a compression tester on all four cylinders lol.
__________________
Quote:
Originally Posted by crimsonrockett View Post
Such a good signature.
TheRealSy90 is offline   Reply With Quote
Old 02-02-2017, 08:06 AM   #6
RalliartRsX
Post Whore!
 
Join Date: Apr 2006
Location: Maryland
Posts: 4,753
Trader Rating: (32)
RalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfection
Feedback Score: 32 reviews
Quote:
Originally Posted by TheRealSy90 View Post
150/160 with 9:1 pistons? My stock unopened s13 sr will do 180 on a compression tester on all four cylinders lol.
Standard compression for a SR20DET @ 8.5:1 compression ratio according to the FSM is 156..........
RalliartRsX is offline   Reply With Quote
Old 02-02-2017, 08:51 AM   #7
mewantkouki
Zilvia FREAK!
 
Join Date: Nov 2007
Location: Orlando, Fl
Age: 35
Posts: 1,221
Trader Rating: (36)
mewantkouki is making a name for him/her selfmewantkouki is making a name for him/her selfmewantkouki is making a name for him/her self
Feedback Score: 36 reviews
Quote:
Originally Posted by TheRealSy90 View Post
150/160 with 9:1 pistons? My stock unopened s13 sr will do 180 on a compression tester on all four cylinders lol.
Your stock unopened SR has carbon build up on the tops of the pistons. That's why you're getting 180psi.
mewantkouki is offline   Reply With Quote
Old 02-02-2017, 10:31 AM   #8
TheRealSy90
Premium Member
 
TheRealSy90's Avatar
 
Join Date: Mar 2009
Location: Maricopa, AZ
Age: 30
Posts: 7,679
Trader Rating: (10)
TheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant future
Feedback Score: 10 reviews
Good, cause it runs like a raped ape.
__________________
Quote:
Originally Posted by crimsonrockett View Post
Such a good signature.
TheRealSy90 is offline   Reply With Quote
Old 02-02-2017, 02:39 PM   #9
gaz_moose
Zilvia Member
 
Join Date: Mar 2008
Location: engerland
Posts: 242
Trader Rating: (0)
gaz_moose is an unknown quantity at this point
Feedback Score: 0 reviews
Quote:
Originally Posted by hanzbrady View Post
Rebuilding engines cost more money.

that's why I got no money left. the simple rebuild became out of control.

guess I will just take my chances!!
gaz_moose is offline   Reply With Quote
Old 02-02-2017, 05:32 PM   #10
Kingtal0n
Post Whore!
 
Kingtal0n's Avatar
 
Join Date: Jul 2005
Location: South Florida
Age: 38
Posts: 4,648
Trader Rating: (17)
Kingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond repute
Feedback Score: 17 reviews
Send a message via AIM to Kingtal0n
I've never tested a used sr20det and come up with more than 130~psi. They all ran fine, great even.

from 8.5 to 9:1 compression is so slight, you won't notice, the computer wont notice, nobody is going to notice. If you think about it in reverse, at 130psi the original 8.5:1 OEM compression is probably down a notch, and it still runs fine. So up a notch, down a notch, same difference.
Kingtal0n is offline   Reply With Quote
Old 02-02-2017, 07:56 PM   #11
TheRealSy90
Premium Member
 
TheRealSy90's Avatar
 
Join Date: Mar 2009
Location: Maricopa, AZ
Age: 30
Posts: 7,679
Trader Rating: (10)
TheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant future
Feedback Score: 10 reviews
Idk, tested mine with throttle body open and 180 on all four.


Sent from my iPhone using Tapatalk
__________________
Quote:
Originally Posted by crimsonrockett View Post
Such a good signature.
TheRealSy90 is offline   Reply With Quote
Old 02-03-2017, 04:26 AM   #12
gaz_moose
Zilvia Member
 
Join Date: Mar 2008
Location: engerland
Posts: 242
Trader Rating: (0)
gaz_moose is an unknown quantity at this point
Feedback Score: 0 reviews
@therealsy90... I wonder if you have NA pistons or something.

@kingtal0n... that was where my thoughts lay. ive seen sr20's that still run with 110psi, they were gutless but still ran non the less.
gaz_moose is offline   Reply With Quote
Old 02-07-2017, 02:23 PM   #13
pacotaco345
Zilvia FREAK!
 
pacotaco345's Avatar
 
Join Date: Jan 2010
Location: SoCal/Ft Worth TX
Age: 27
Posts: 1,549
Trader Rating: (5)
pacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond repute
Feedback Score: 5 reviews
Quote:
Originally Posted by gaz_moose View Post
@therealsy90... I wonder if you have NA pistons or something.

@kingtal0n... that was where my thoughts lay. ive seen sr20's that still run with 110psi, they were gutless but still ran non the less.
I just pulled my motor out that had 110 psi and that thing SCREAMED. I just wasn't comfortable with those numbers. Are you on 91 or 93? I'd be kinda wary running 9:1 on 91 octane.. but just don't go driving uphill in hot weather at low rpm and you should be fine.
__________________
pacotaco345 is offline   Reply With Quote
Old 02-07-2017, 02:30 PM   #14
RalliartRsX
Post Whore!
 
Join Date: Apr 2006
Location: Maryland
Posts: 4,753
Trader Rating: (32)
RalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfection
Feedback Score: 32 reviews
9:1 on 91 octane is nary an issue.........especially with the tuning solutions we have. Many new turbo vehicles (non direct injection) run 9:1 and up on 91 octane

Commifornia max octane rating is 91, less we forget (which I see SoCal in your location, so you should be well aware lol)
RalliartRsX is offline   Reply With Quote
Old 02-07-2017, 02:36 PM   #15
S14kouki805
Zilvia Addict
 
Join Date: Aug 2014
Location: California
Age: 39
Posts: 808
Trader Rating: (5)
S14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud ofS14kouki805 has much to be proud of
Feedback Score: 5 reviews
Quote:
Originally Posted by TheRealSy90 View Post
Idk, tested mine with throttle body open and 180 on all four.


Sent from my iPhone using Tapatalk
Excuse my ignorance but are you SUPPOSED to do a compression check with the throttle open?
S14kouki805 is offline   Reply With Quote
Old 02-07-2017, 02:40 PM   #16
pacotaco345
Zilvia FREAK!
 
pacotaco345's Avatar
 
Join Date: Jan 2010
Location: SoCal/Ft Worth TX
Age: 27
Posts: 1,549
Trader Rating: (5)
pacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond repute
Feedback Score: 5 reviews
Quote:
Originally Posted by RalliartRsX View Post
9:1 on 91 octane is nary an issue.........especially with the tuning solutions we have. Many new turbo vehicles (non direct injection) run 9:1 and up on 91 octane

Commifornia max octane rating is 91, less we forget (which I see SoCal in your location, so you should be well aware lol)
I just re-read OP's post, he's on 100 RON which is like our 93.. But if the car was tuned for his old setup on 100 RON then that's where the issue lies.

OP I'd ask your tuner how balls to the wall he went on the last map, if he left some on the table you should be fine, but if he was on the edge of knock trying to squeeze every last hp out of the car then you might have an issue.
__________________
pacotaco345 is offline   Reply With Quote
Old 02-07-2017, 02:41 PM   #17
pacotaco345
Zilvia FREAK!
 
pacotaco345's Avatar
 
Join Date: Jan 2010
Location: SoCal/Ft Worth TX
Age: 27
Posts: 1,549
Trader Rating: (5)
pacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond reputepacotaco345 has a reputation beyond repute
Feedback Score: 5 reviews
Quote:
Originally Posted by S14kouki805 View Post
Excuse my ignorance but are you SUPPOSED to do a compression check with the throttle open?
yes messagelength
__________________
pacotaco345 is offline   Reply With Quote
Old 02-08-2017, 04:32 AM   #18
gaz_moose
Zilvia Member
 
Join Date: Mar 2008
Location: engerland
Posts: 242
Trader Rating: (0)
gaz_moose is an unknown quantity at this point
Feedback Score: 0 reviews
wait how can you guys have 93 that is 100ron? surely it is 93ron?? man your country is crazy.

tbh it was originally tuned about 8 years ago so my tuner wouldn't remember a damn thing about it. im only going to cruise it around not go balls to the wall so I think I should be fairly safe if I put fresh fuel in the tank when I use it.
gaz_moose is offline   Reply With Quote
Old 02-08-2017, 04:36 AM   #19
RalliartRsX
Post Whore!
 
Join Date: Apr 2006
Location: Maryland
Posts: 4,753
Trader Rating: (32)
RalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfection
Feedback Score: 32 reviews
RON - Europe/UK (anywhere outside the US) octane unit
Octane - US octane unit
RalliartRsX is offline   Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 10:36 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
vB.Sponsors
Copyright © 1998 - 2019, Zilvia.net™