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wat would be a good compression for a gt35r

codeofdastreets

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Aug 30, 2008
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Palm Harbor FL
im looking to build up a 6 bolt motor, but i haven't decided wat compression to do.im looking to run a gt35r nd i wanna make the most power i can safely street/ track car(you know got a keep them hondas in place lol) i was thinking 9.0.1 but idk if that is safe to run a turbo like that. can u guys give me tips nd advice thanks
 

I am running 8.5:1 Ross pistons on a 37r, but 9:1 would be good as well. Infact I think I should have gone the 9:1 route. Next build. So do the 9:1.
 

prove_it

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Jul 3, 2008
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Sioux Falls, SD
1000 horse evos run 9:1 compression.
You can go that high, but you'll want race gas or if you can get E85 plan to run it.
If you do and plan on running 30lbs or so you'll want to spend the money and get ARP L19 studs.
the 9:0 compression piston will also help your spool time too.
 

Brianawd

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Apr 18, 2005
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Portland OR,
If you can get e85 where you are I would go 10.0:1 or 11.0:1. If you can't then go 9.0:-9.5:1
 

bazeng

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Feb 6, 2003
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Melbourne, Australia
Wow, thats high comp guys!

I would have thought something like mid to low 8's for ideal street performance with big boost.

I agree that the high comp is good with race gas though...
 

slugsgomoo

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Oct 16, 2003
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Tacoma, WA
static compression increases power as well, hell, look at static versus dynamic cylinder pressures and timing curves. Obviously it's a compromise, but I think that with a good tune even up to 9:1 or 9.5:1 is just fine on pump. Obviously you'll sacrifice a few pounds of boost and a bit of timing, but it should all even out.

You'll simply get a car that's nicer to drive off boost, spools faster, gets better gas mileage, etc. /ubbthreads/images/graemlins/dunno.gif

today we have cool things like stand alone ECU's and dsmlink and having to adjust the timing curve to allow for higher compression isn't the stumbling block it once was.
 

bazeng

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Feb 6, 2003
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Melbourne, Australia
Even so, with higher comp and low boost vs lower comp and high boost, in our experiences tuning we've found that the lower comp makes better power on pump fuel.

On race fuel on the other hand, the higher comp engine benifits since the fuel doesn't really detonate.

Is anybody on here with higher than a 9.0 c/r?
 

it depends on how much boost you want to run in order to make the power you want



8:5:1 =higher boost to make power


9:0:1 =lower boost to make power
 

All i got to say is that my 9.5 comp 2.3 runs freakin great off boost. Im still breaking-in the motor so i havnt poured the coals to it yet. Ive got the tune good for just normal driving so i have yet to see what it acts like with more boost.
 

FCR

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May 17, 2008
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121
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Orlando, FL
I have 9:1 comp on my VR4 and runs great the power band, spool, etc. I make 440hp and 435 tq on pump gas (GT30R and 2.3L) only 18 psi /ubbthreads/images/graemlins/worthy.gif /ubbthreads/images/graemlins/worthy.gif /ubbthreads/images/graemlins/worthy.gif /ubbthreads/images/graemlins/worthy.gif
 
Last edited:

1990ggsxnj

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Nov 21, 2008
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525
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Blackwood, NJ
I'm pretty sure once you upgrade cams, that effects compression, scavaging, etc making it easier to run the higher compression so if you're looking for an excuse for bigger cams, bump it up to 9:1 /ubbthreads/images/graemlins/grin.gif

Back when I did have both my Eclipse GS (n/t) and GSX I definately noticed a differance off the line, what with the drivetrain loss and lower compression. If I floored it in the n/t it would take off, but the GSX took a second.

FCR, out of curiosity, what cams are you running?
 
Last edited:

FCR

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May 17, 2008
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121
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Orlando, FL
FCR, out of curiosity, what cams are you running?


I used HKS 264.......... /ubbthreads/images/graemlins/devil.gif
 

codeofdastreets

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Aug 30, 2008
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65
Location
Palm Harbor FL
rite now the motor has a hks 272 cam but the motor has a stock bottem end im in the prosses of builting it up
 
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