vaporboy12

i found this one from like 2 years ago i havent really been on the dyno much since then. just tuned it at the track that was with a 9:1 cr motor and a t3/67ho at about 17 psi of boost..

JDogg

if its built and tuned right really low compression isnt bad

example. a friends engine, b16 stroker, 84mm crank, 84mm bore, b17 rods with a jg sheetmetal intake manifold, huge throttle body, one fab bottom mount manifold, 4inch dp and a gt4088r.

due to some really really shitty charge pipe its way down on power and takes forever to spool, but it has the normal -18cc wiseco dish and there has been a good ammount of material taken out of the chambers, this motor is probably around 7.5:1 compression. this motor is also one of the strongest turbo hondas i have driven when its in lag, it pulls really strong in lag. it only made 475hp on 20psi with pump gas, but from what i have seen by changing to proper charge pipe it'll make around 550 when we redo the charge pipe. his mess is a hodge podge of pipes we had laying around, some of it is smaller than 2inches, some of it is 3 inches, the outlet on the turbo is 2.5 inches... so yeah anyway....

if its turbo and gona run mainly on pump gas built it w/real low compression

Pnoyej6

Im running on pump gas daily driver thats why i decided with low compression

boosted92

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">if its turbo and gona run mainly on pump gas built it w/real low compression</TD></TR></TABLE>

Agreed. I have a friend running a built Z6 at about 7.5:1 compression, it's not that bad off boost and the ability to run 20+ pounds of boost on pump gas without fear of detonating sure is nice.

JDogg

just got done with another pretty low comp b16 tonight, gt3071r on 14lbs made 385 and on 20lbs it made 466hp/350tq on pump gas of course. its being held back by the manifold at this point, but its more than enough power for a daily beater. it has wiseco -18cc pistons, stock b16 crank, rlz valve job, phantasm USA blending of the valve job/chamber work. probably right at 8:1 compression.

most_hated_crx

keep the stock compresion 10.0.1 , like cortney said, lowering compression is for people who can't tune lol no offense but I'd say stay with the same compression and get a good tune

joppe

Problem is that high compression and high boost you have to decrease you ignition advance. That raises egt and you cannot run long time @ WOT.

Im rebuildin my engine and i have made decision to stay below 9:1cr. I dont care so much lower rpm torque, i dont pull caravan with my honda civic.

Ryan15

my dsm felt very weak out of boost compared to my stock compression gsr motor

Quickgti1.8t

9:1 here over 25psi on pump daily driven on a 35r . But i dropped a valve lol so now i bought some 8:8:1

JDogg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ryan15 &raquo;</TD></TR><TR><TD CLASS="quote">my dsm felt very weak out of boost compared to my stock compression gsr motor</TD></TR></TABLE>

haha... are you really comparing a 4g63 to a honda motor..

and its not about being a good tuner or not... its about how much power you want on what kinda gas. there are limitations and you should build your motor accordingly.

Tony the Tiger

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by joppe &raquo;</TD></TR><TR><TD CLASS="quote">Problem is that high compression and high boost you have to decrease you ignition advance. That raises egt and you cannot run long time @ WOT.

Im rebuildin my engine and i have made decision to stay below 9:1cr. I dont care so much lower rpm torque, i dont pull caravan with my honda civic.</TD></TR></TABLE>

Countless high CR motors I've tuned does not even have the same high EGT's as low CR motors. High CR offers way more complete combustion given proper timing.

If you are retarding the timing on a high CR motor to the point that EGT's would skyrocket, it's time to move onto higher octane. Again, key being power vs compression vs octane. If you want 400-450 WHP on pump, 9.0-9.5:1 is fine and dandy. If you are looking for 300-400 WHP, 10.0:1 is just as good as any other compression. With 300-400 WHP, you don't put in a GT35R or something huge. You simply don't run 10.5:1 CR on a GT42R, or 8.1:1 with a GT28RS. Size matters.

Either way, the motor is f*cked if it isn't tuned at those power levels regardless of compression.

Guys often get too suckered into thinking that compression only helps off boost regions, and everything is fine once boost hits. Hop in a high compression turbo car on the streets and you will never even think of touching a low CR slugger.

Maybe pack some slicks when you go to work so maybe you can grab some traction starting at 4th gear if you go with low compression. It's all about power transition on FWD hondas. The moment you go from a "Civic DX" with under 140 WHP to a V8 smoking 400+ WHP beast, do you really think the car is going to anywhere?

For a track car, that's a different story. For a track car, hell I just chug a can of race gas and who the hell cares about compression ratios.

nihad

iTrader: (2)

I have 7.7 1 compressin on my aries pistons and eagle rods. Its a d16a6 block and z6 head. Do you think i am going to be all right. Is it safe most psi i will run is like 20-24. But daily like 10-12. thanks