Stock is 10.3:1

When I build my Vortech YSI Motor it will be 11:1

not much different from 10:1 to 10.3:1

What will you be Doing with your car?

 

Have the shops you called built any VQ engines for supercharged applications?

 

11:1 would be sweet, but I may go with 10.3:1 in the end along with a ProCharger... we have 93oct here in IL.

back on topic


Zquicksilver

 

I have CP 10:1 pistons...
wish I woulda went with lower.
I purchased the pistons when I had a SC. Now with the APS TT, I'm limited.

 

why are you limited???? if you follow alot of the modern mainstream builds they are runinng more and more compression.

its not like that APS kit is a monster in terms of boost potential.

 

+1, with adequate fuel and good tuning could easily have some good numbers? a

 

i didn't catch anyone addressing this so i will:

cams aren't needed at all with a 450hp goal. Stock cams have easily been run up to 600hp. These are crappy flowing domestic heads on the vq so cams really won't open up a ton of power potential like they do on american cars. If you look at my power curve with ported heads and cams verses stock heads and cams they aren't much different down in the 450hp range. Mine actually is slower to produce torque due to the flow. That all changes once you start pushing some high flow high horsepower though.

cost to benefit ratio is very low with cams on our cars unless you are talking about 600+ hp

 

So, with a built bottom end and 11:1 compression, you are saying it is safe to run a 2.87 pulley?

 

of course. you just adjust timing or run a higher octane fuel.

anything can be tuned to work.

 

I'm not sure. Maybe I should say the octane limits me. This is not a modern build, I built this motor way back. Maybe it's just the turbos getting close to their max.
I was told that it was having a hard time past 12 lbs with 91 octane. He put a mix of 100 octane and was able to make a tune with 14.5lbs.
At that point, the 11.5lb actuators were giving up. I think I didn't preload them enough.

One air filter is located directly behind the huge tranny cooler and the other air filter is directly behind the oil cooler. The tuner suggested I should reroute the filters.

 

definitely relocate those filters. 200* air coming into the turbo isn't very good for intake temps.

 

I think 9.5:1-10.0:1 is ideal for a supercharged VQ application. The stock compression works well on the lower boost settings but its just a touch high when it comes to the 2.87 pulley and higher. I find that from the 3.12 to the 2.87 pulley I need to pull more timing above 5500, then i do when going from 3.33-3.12, from a lb of boost to timing ratio...if that makes sense. I actually just put in a production run of 9.7:1 Wiseco pistons. I think they will work great on all the vortech cars and smaller twin cars looking to make 500hp-550hpish. I think out of boot response will feel good and have the slight reduction in compression to run safe on 91 or 93 octane under all conditions.