Im running a Greddy 18g kit on a Stock Ls..
i have a 2.5 inch dp with a stock cat and stock exhaust,
Starion Fmic with 2" hot side piping and 2.5 from intercooler to turbo.

I am running 7psi and wondering if my spool times are fine? Car seems to spool up kind of late. in second gear i get full 7psi by 4500 rpm and 3rd gear by 4200ish RPM.. from my understanding the 18g is a fairly small turbo and should spool up sooner.

Anybody have any input.? thank you

 

That sounds like its close. Stock ls comes with around 9:1 compression stock I believe and 18g is some what small but not tiny..sounds like your in the ball park, have you checked for boost leaks?

My greddy kit on my single cam gets full boost around 3500rpms, but thats with a much smaller turbo I think td05 or somthing like that...

 

i have checked for boost leaks.. i think the cause is the stock cat and stock exhaust.. i just think boost is kicking in late.. like it starts to spool at 2500 rpm but full boost at 4200 rpm... thats a long time just to make 7 psi.. \

could the it bethat my wastegate line is causing the wastegate to open early ? because i dont hav eit going from the intake manifold.. i have it going from my charge pipe..

 

Stock exhaust is going to kill the flow of any turbo. Take off the exhaust and you'll feel the difference.

 

My 18G on a stock b16 with a 3in dp and catback@12psi. its hard to see when full boost is acheived but on 4th gear pulls it was fully spooled before 4,500rpm

 

were you having boost creeping problems using the internal wastegate? I'm gonna be pushing my 18g to as far as it will go with the internal wastegate. I'm hoping to get about 315 WHP out of it.

 

You have it hooked up correctly...

Boost leak test, and than upgrade your exhaust. Restrictive exhaust is a killer.

 

open dump FTW

 

sorry greddy is a internal wastegate so cant do opendump.. lol maybe ill look into a cutout... i like the look of my car with stock exhaust...haha worries people when they hear a blow off valve.. haha

 

I have done open dump on my internally wasted 18g. I had no choice, my exhaust broke, and I wasn't dragging it around. There's no reason you can't do open dump on an interally wastegated turbo. I understand you're trying to go for the nice clean, and stealth look, but you need a good exhaust.