GRTechnologies

This is for all you engine builders.
Lets here what compression everyone thinks is better.
And if you were building a motor for yourself what compression would it be?
And why?

BoM

low compression for better reliability on pump gas.
higher compression for a racecar (more power) on race gas.

im getting a 2.0L block built with 9:1 compression. gonna try to run 30lbs.

CRX SiR T

both can be very drivable and used as a daily driver.

low --> easier to tune, allows biggest margin for error (thats why many street tuners choose low compression)

high --> quicker spool, more power w/ less boost, harder to tune, small margin for error

if high compression is built and tuned right, it will be signifigantly better than low compression

GRTechnologies

should make power @ 30 psi.

GRTechnologies

cool

alpha

My B16a block is at GEM right now. I'm using 9.2:1 pistons.

Flamenco-T

b18C1, Wiseco 9.8:1...with 60-1, I can't imagine being on 8.5 or 9.0:1 CR

alpha

When I get my overbored Honda head gasket it should bump compression up a little bit.

Diego Boost

I agree with everyone here so far.

b18bturbo

mixture of compression is good a little high and little low. I like stans idea 9.8:1 its the way of the future

PM-Performance

high compression feesl great in and out of boost and dont need alot of boost to get great powr.
but tuning can be a bitch sometimes.
have a really good tuner and good management if you go high cvompression beucase it isnt as forgiving as said above.

xonn

My current compression is 11.2:1 and I'm considering add a supercharger... I'm running a custom grind from with lots of duration so the dynamic compression of the engine really isn't that high. My goal is to run 7 psi on top of what I currently have. In GA, 93 octane is plentiful and is currently all I run in the engine. Comments?

Danger

i went ROSS 10:0 compression pistons for my built b18c5 . i havent decided what turbo to use yet . i have a standard t3t4 left over from my old car but i dont think it would make enough power for the times im looking for .

Pelican

<9:1 is too low
>12:1 is too high
IMHO

sharkcohen

Running a large amount of duration for high compression on an NA engine is fairly standard. Running high duration on a boosted engine is a no no, unless you like blowing your boost pressure out your exhaust valves.


[Modified by sharkcohen, 4:57 AM 3/5/2003]

import palace

i personally prefer a higher cr for turbo apps. cause you eliminate a bit of the turbo lag and you produce more power in the long run. yes there is a finer line as far as errors in tuning are concerned but a standalone can eliminate alot of those issues.

MiraiZ

9:1 is clean (LOL)

xonn

So basically it's an inefficient way to make more power... I'd be loosing more boost than it would be worth..

MotorMatrix.com

I like lower compression and a ton of boost. Lag is your friend on the street. I'm staying 9:1 on my new setup and stock bore basically .020 over. GR on the other hand is going 10.5:1 on some alky. Sick Bastard!!!

I see your trying to get rid of the trial user status huh?? 17 posts Big dog!!!


[Modified by MotorMatrix.com, 1:00 AM 3/5/2003]

DIRep972

iTrader: (1)

low compression
- more timing
- more boost
- more lag
- less efficient hp
- more room for error

high compression
-less timing
-less boost
-quicker spool
-more efficient power
- requires more precise tuning

Id like somewhere inbetween.

rOby

10:1 here

boosted hybrid

8.8~9:1 here. I prefer 9:1 compression, even after having 11:1 for awhile. You can still make very good power with 9:1 compression. My goal is 400whp on pump gas with my compression and engine/turbo kit. Its very realistic, and adds a little safety blanket for tuning and overall reliability.

highbrid

me = 10.4:1 cr

pissedoffsol

im running (or will be rather) 9.1 pistons in a gsr with a b16 head, so that drops me to lik 8.8. I, like motormatrix, like the idea of lag in a street car. I also think that high compression is for N/A guys. We have turbo's to make up the rest of our effective compression

darkracer

low, how low can ya go.... i would run about the stock 9.1:1 cr or 9:1 around 9:1 sounds nice to me.