I'm not really sure what that's supposed to mean? Is he supposed to put the 8.8:1 pistons later when he gets the turbo kit IE just tear it all apart and rebuild it? That sounds like a poor financial decision lol.

Anyway...

OldManZ350 has a great point. If you're going to really push on the built engine you want the low compression (I probably would do it at anything projected over 600whp). If you want a simple low boost street car, you can definitely make even a 10.5:1 work with ethanol or water meth + pump. Maybe even pump if your area has something at least equivalent to 95ron.

 

I think he meant that if he goes with the 8.8 out of the gate that he won't be satisfied with the performance on a Vortech and that he will want to upgrade to a turbo sooner than later.

Personally I went with a 9.5, and not a higher CR because I am stuck with 91 oct as 'premium' fuel here where I am... E85 is available but the stations are few and far between and I did not want to be stuck hunting for a station when low on fuel.

 

Same here. I was knocking a little with stock 10.3:1, a 3.12 pulley, SCi impeller, and 91 octane. I dropped cr to 9.5:1 because I upgraded to an Si impeller, larger cams, and might drop to a smaller pulley. 91 octane sucks.

 

It means that I'd recommend going with the 8.8:1 or 9:1 on his current build only if he intends to install the turbo kit now or in the very near future (not 2 years from now), because it will be a dog on his Vortech setup. 99% of Vortech guys don't push their Vortech beyond 450whp, let alone to 550-600whp+ where 8.8:1 would be prudent. I didn't see the OP state that he was going for big #'s on the Vortech either.


OP,
What are your horsepower goals and intended use for your car? Daily driver? Any track use? If so, what kind of track use?

 

Oh lol well then I miss understood you. Although depending on a lot of things that motor may be still alive or even in strong condition 2 years from now.

He did say he's going with a 928 impeller and 2.87 pulley. Don't know how close to 500whp that would put him... I guess it depends on other mods. Probably should pick up some cams depending on the motor if he's going with longtubes etc.

I was also going to say I'd go with the 8.8's so you could spray down the road and make more power easily. But 9's would be fine with a small shot for sure.

OP if you go with anything close to a 10 just make sure you get FI and not NA pistons: NA pistons will be thinner and 10:1, not just 10:1

 

I will go 8.8 becuase i will want to put like 400-430whp and here cars with station gas are all between 350-380 because of knock.. i want it to weekend street drive car and i dont want to push it to the limit... i will go low even in low rpm i feel it doggy... i have a question for all of you... i have long tube header and i feel that jt have to much free flow in low rpm and i have very low torq.... i can pht a magnaflow H muffler or resonator on my Y pipe??? i have nismo cat back...

 

X pipe > H pipe.

X pipe will help with scavenging from the cylinders more equally and help with TQ I believe.

 

Why not 9:1 and water/methanol injection? It will get you more power and less knock for sure.

Long tubes will reduce your low end usually. I would upgrade your Y pipe to a twin 2.5" to 3" and then a straight through muffler at the end (vibrant, magnaflow, borla all of them make 'turbo' mufflers).

 

here is a pain in the *** look for methanol i think... tomorrow i will call my tuner to see if he had tuned water meth cars...
I dont know to much about that kit... wich one its the better cheaper kit?? i know snow performance and aem....

 

i was looking for some information and this look interesting...

http://www.turbomirage.com/water-alc...arts-list.html

 

if you are only looking for mid 400s, there's absolutely no reason to build the motor at all unless yours has poor compression/leakdown.

I wouldnt do anything less than 10:1.

 

I don't understand why nobody brought up the fact that static compression is always adjustable on the vq because of the cam phasers, stick to 9.5+ make the rest up with good tuning and gasoline, focus on good rods,good bearings and a competent engine builder for longevity instead.

 

I think you mean Dynamic Compression!!!!!

 

Lol was too early in the morning, I meant dynamic. I meant to say I'd leave static compression at 9.5+ min.