Problem with too high of boost

[cchilly]

This spring I put a 3" downpipe on the car and a new pypes exhaust.

I'm running a stock actuator with a RJC MBC with a stock turbo.

Well last fall I had the boost around 14 to 15 psi according to my PL and 3 bar MAP. RJC was adjusted close to middle of the treads.

Once I completed the exhaust upgrades I took it out for a run and the PL was showing 22 psi

I now have the RJC on screwed in to one and a half threads and I can't get the boost any lower than 16 to 17 psi. Sometimes when testing I can get it creeping up to almost 19 psi. I also confirmed the high boost with my VDO boost gauge as well, so it doesn't seem like the sensor is bad.

Any thoughts or suggestions. I have a TTA intercooler with Dutt neck that I want to install, but I don't want to make my problem worse with freeing up more boost.

Thanks
Chris

 

[notacarlo]

Stock turbo?

Exhaust pressure might be overcoming the old worn out factory wastegate actuator. How easy is it to manually pull on the actuator rod?

 

[mikestertwo]

Sounds like you have to open up the wastegate hole in the exhaust housing on the turbo. You have increased your exhaust flow to the point where the stock wastegate port cannot bypass enough of the exhaust gasses to control the boost.

 

[cchilly]

Thanks for the replies.

Notacarlo - yes it is a stock turbo. The waste gate actuator seems pretty hard actually to pull out. I'm not sure what it is supposed to be, but you have to give it a pretty good pull to get it moved out.

mikestertwo - Is this common to have to port a stock turbo? I have read about porting the bigger turbos but not much on the stock ones. I really don't have a lot done to the car. Check out my sig.


Thanks
Chris

 

[SS/GN]

Try this

Take the rjc valve apart and clean,I use brake and parts cleaner.Ball could be stuck on the seat.Good luck!Also check hoses.
Kevin

 

[cchilly]

Thanks for the input Kevin

I took it apart when adjusting to make sure everything was ok. Looks brand new inside. The hoses looked fine when I was taking it apart, but I will check them again.


Chris

 

[mikestertwo]

Thanks for the replies.



mikestertwo - Is this common to have to port a stock turbo? I have read about porting the bigger turbos but not much on the stock ones. I really don't have a lot done to the car. Check out my sig.
Thanks
Chris

I had to open the port on a stock turbo when I went to a THDP and a Hooker 2 1/2" exhaust system.

 

[cchilly]

Thanks mikestertwo, I will look into that.

I have another question about the THDP. I noticed the puck wouldn't open a lot because it hit the side of the pipe. Say from the vertical it would go about 45 degrees and then stop.

Well I was checking out the stock elbow tonight and noticed the puck opens a full 90 degrees.

Is that normal for the 3" downpipe to not have the puck open all the way up? Maybe this is causing my problems.

 

[dsa87gn]

I had to open the port on a stock turbo when I went to a THDP and a Hooker 2 1/2" exhaust system.

I couldnt keep my boost levels down when I added my THDP/ Hooker 2 1/2 and Cold Air Kit on my stock turbo car. Tuner style I would get 15+ no where near full throttle. Spent alot of time with different actuator new turbo hoses etc.

Instead of porting the WG hole, I added an alky kit:biggrin:


Funny thing was I then had problems getting past 20#with a stock adjustable.
I had to add a manual boost control.

 

[mikestertwo]

I have another question about the THDP. I noticed the puck wouldn't open a lot because it hit the side of the pipe. Say from the vertical it would go about 45 degrees and then stop.

Well I was checking out the stock elbow tonight and noticed the puck opens a full 90 degrees.

Is that normal for the 3" downpipe to not have the puck open all the way up? Maybe this is causing my problems.

That's not your problem. 45* is more than enough. In normal operation the puck moves a lot less than that when controlling boost. After a certain open angle the port becomes the restriction not the puck.

 

[Razor]

Why put a boost controller on a stock setup you need to leave at 16 PSI

The reason for a boost controller typically is to "increase boost" not lower it. And the stock adjustable actuator with the factory bleeder on the valvecover is sufficient.

If you mess with boost and it overboosts.. you will detonate the motor unless you have octane. This will lead to a blown head gasket, crunched brearings, blown pistons, etc.. sooner than latter.

Take the RJC off and use your factory actuator for control. If you can get race gas or put an alky kit on it.. then you can play with boost.

HTH

 

[cchilly]

I thought the RJC valve was also to help eliminate the WG opening early and bleeding off some boost at lower pressures.

When I bought the car it never had the stock WG controller hooked up. I'm not sure if I even have everything needed. It had some air compressor regulator used to bleed off boost. I switched to the RJC MBC thinking it was better and would be easier to use.

I'll try putting it back to stock and see how that works. The only reason I was wanting to lower boost is because I'm seeing some knock on the PL and I want to see if it was false knock or not. Quickest way is to decrease boost.

If mikestertwo is right about porting the hole, will going back to stock even help me? I'm guessing it won't.


Thanks for everyones feedback. I appreciate the help and input.