Wastegates have been checked, taken apart and new springs put in maybe 2 yrs ago when we were troubleshootning the issue. Even looked at the gasket being pinched in the wastegates.

BOV is a new Tial installed maybe 2 yrs ago with limited use since the car has been worked on mostly.

 

You have a heck of a combination, and IMO, that 1.10 TS hotside housing is simply too small and is choking that engine at higher boost pressures. Put the biggest housing on it that FP can get you and watch that car come alive upstairs.

 

well I currently have the 1.15 which Aaron @ English Racing suggested as the 1.32 wasn't out yet as of Jan of this yr. Now when I bought the TS3794HTA it had the 1.00 on it. It's been proven that this turbo with this housing can handle at least 800+ and even then the housing isn't maxed out. This coming from the threads that Aaron made just a few weeks ago.

But if it wasn't for him and his advice I'd agree with you and would change it.

It never had the 1.10 on it.

 

A boost leak doesn't cause no increase of power with an increase of boost.

 

Well, at this point all you are doing and can do is guess... If you want to change that, you will have to check backpressure. What I did was weld a port onto a header tube so that during a dyno session I could hook up a gauge to measure back pressure during a pull.

Also, I'm not wanting to argue or go against anything Aaron told you. But, I would just say that you need to remember that you have a pretty good sized engine at 2.4L. On a 2.0L that 1.15 hotside might be enough, but on a 2.4 it may be a restriction at higher pressures. Also, you have a higher compression engine, which needs a free-flowing hotside. Just some things to consider...

I would guess that you are seeing at least 2:1 in terms of backpressure. By the time you hit 35psi it might even be closer to 3:1, which is horrible and will certainly kill power at higher boost pressures. For a street car I like to see that number down closer to 1.5:1

 

This is what Brian @ FP said to do next.

 

Question: What size runner should I be using with this?

 

Again, I know that there are people out there who would disagree with me on this, but at a bare-minimum you need a 1.5, but IMO, your combo is ideally suited for a 1.75 header tubing.

 

My limited mechanical and fluid dynamics understanding makes me agree with you and its one of the options I have on the table.

 

Over the years Bigger exhaust more power unless you have a little turbo that doesnt need it.

 

If it is worth anything I run a small runner 1.25 header and a T4 1.15 housing. I am having Geoff build me a bigger runner "I believe I'D is 1.67" manifold. I was thinking about trying the 1.32 housing but I want to see what the manifold does first for power and topend. I'll share my results once it is done.

 

I'm sorry are you stating something or asking. The exhaust has been on the car since early 2007. Way before this issue happened. Is that what you were getting at?

 

you need a tighter running to keep exhaust volecity at its peak... if your speed falls you spool will be hurt... i would say at most 1.5 but who really knows...

as for the engine itself... pre turbo back pressure will be there regardless... its a turbo... ensure your o2 housing isnt seeing any... they make a kit to plug into a o2 sensor fitting for back pressure testing... make sure you timing is right as well... not only visually but cam centerline and all that bs... if your cam was ground off by a degree or so then it would have serious effects as well.
a leak down test will identify if your rings were ground wrong or are worn to large... or perhaps a valve isn't responding properly... hope i help. doubt i will if you have been talking to buschur and english...

 

No I've been following you over the years and why I chose the TS as well. I believe the current size manifold on the car now is 1.25 as well. Again, I bought the manifold with the 4088 back in 2009 and the manifold may have been adequate then but may not be now. It's one of the things I will try doing when I start ruling stuff out. Unfortunatly I couldn't test this theory as the 4088 is long gone!

 

oh... a serious induction cleaning might help a bit as well... last time i tore my car down i had something with the consistency of melted plastic in my head ports and intake runners... certainly wasn't helping performance...