Ok...First things first. I had a MASSIVE intake manifold leak for a while. It turned out to be the manifold gasket (LIM --> UIM). Stupid me never noticed that the gasket was NON EXISTANT!. I never even noticed it when I pulled the manifold off to fix my 90 degree coolant hose. So...something clicked in my head and I knew that it was the gasket. I went to the stealership and picked one up for a whole 4 bucks. I installed it today and found another leak a nipple coming off the LIM at a slight angle towards the drivers side. I imagine it's for the EGR valve casue it was sucking air into the manifold. I capped it and My car idled much better. I now need to adjust my TPS to finalize all of the issues. But....The last thing that I noticed was the cars increase in responsiveness. I didn't look at my boost gauge at first but when i actually did look at it, it read that I was boosting at ~8 - 8.5 lbs. I was only boosting at 6 earlier on in the day with the manifold leaks.

What do you guys think? 6 lbs to 8 lbs instantly? Is it feasible? And what is the nipple I found that was sucking in air to the LIM? Is it for the EGR? I'm asking about that nipple because my engine didn't come with an EGR. It's a Jspec.

Thanks guys!
-Nader

 

Oh yeah,

RB 2.5" DP/Presilencer --> single outlet Apex'i N1 as far the exhaust is concerned.

 

the increase in boost is due to you fixing the vac leak. Its a vacuum leak when the engine is idling, but when the manifold is pressurized by the turbo charger, it becomes an air leak.

 

^^ That's what I was figuring.

What boggles me is that I was under the impression that the stock boost was only 4 lbs. If that's the case, how did I gain another 4 lbs? The RB DP/Presilencer should only be a 2 llb boost...

 

stock boost is either 8 or 8.5, somewhere in that neighborhood.

 

Hmmm...I could have sworn that I was told that it was 4 lbs by a rotary specialist....

Well...All is good anyway!

 

well, for an S4, the stock boost should be around 5.5psi. Adding any kind of mods, such as intake, exhaust, etc. will actually raise this boost number. It's due to the airflow flowing more freely.

 

^^ I know that...I've been in the rotary loop for a bit now. still learning of course!

I just found it odd that it would jump poost pressure like that so quickly. Isn't the max that an S4 turbocharger that it can handle something like 10 PSI? What are my limits as to not randomly pop the turbo....

 

12psi seems to be the max that the stock turbo can do while maintaining efficiency. However at those boost levels stock fuel and TMIC are not terribly safe.

 

Yea....Oddly enough, My boost gauge is reading 12 Psi at WOT in third gear now. I don't know what is goin on......

 

do you have a boost controller?

 

No...No boost controller.

My turbo is actin weird now. Boosting like no other but noisy as all hell. At first it was whining as it spooled...now it's making a whoosh sound and whining. I don't get it. I'm scared to drive the damn thing now cause I think that there's gotta be something wrong....

 

It's called boost creep. Pull the turbo and port the wastegate. Not sure about the whooshing sound though. For the time being just use throttle control otherwise you might do some damage.

http://fc3spro.com/TECH/HOWTO/ZWG/zwg.html

 

I have had similer boost creep problems............My 87 TII has 3in turbo back exhaust, fuel cut defenser, CAI........I bought it this way. Well the first day I got it my boost level went up to 15psi on the highway , it got there quick. I've been babying my car since then, I don't go above 10psi. It sucks cause I can't really get on the gas. To solve my problem I getting an S5 turbo & exhaust manifold. I'm going to have the wastegate ported out. I'm also getting bigger secondary injectors cause I will need more fuel. I consulted with an owner of a RX7 shop on what to do. He recommended the things I'm doing. He said the S5 turbo's wastegate ported out will not go above 7psi. So once I get this setup I'll be able to get on the gas .

 

Hmmm...

Good info...Thanks guys

 

i used to boost 15 psi daily on a stock s4 turbo.

 

and then what happened?

 

Did you finally blow your engine? If yes, how long did it take?