So driving home today I noticed the car felt sluggish in 5th.

 

I hit the gas WOT and look at the boost gauge... and, WTF? 2 psi? It slooooowly climbs to 5-6 psi and stays around there.

 

In second, same story, execpt that by around 5000 rpm I get maybe 7 psi.

 

I have a manual boost controller set to 12 psi, and normal behavior is that in the higher gears, it shoots right on up there once you get on the gas.

 

So, what should I look for? probably an exhaust leak before the turbo, right? I swear my car sounds louder now, but it could very well be just my imagination.

 

If it's not a leak, time to go turbo shopping eh? I have a VF11. I'm hoping that a TD04 from a WRX will just bolt right on where the old one was...

 

This is very strange because the drop off in boost seems very sudden. Less than a week ago, everything was perfectly normal. I always thought that when turbochargers go, they go slowly...

Whoa there turbo, there is more than one cause...

 

A. Exhaust leak before turbo (at the heads, or at the turbo)

B. Vaccuum leak (or rather, boost leak... check intercooler piping)

C. Plugged exhaust down stream limiting flow

my check mark goes beside

Tex's "C"

 

could be CCC

 

Classic Cat Collapse

I don't have any cats. Completely open exhaust. I'm taking apart all of my plumbing. Got to be a leak there, somewhere.

Make sure that you also remove any shielding that might be on the exhaust. I once looked at a car whos exhaust looked perfect, but had no boost. Once the shielding was removed we could see the rather large holes in the exhaust.

Wait a second, this is the XT that I owned for a while

 

there was a constant problem with the wastegate actuator mechanism

 

I would examine this area for a stuck open wastegate

 

this might explain the problem

Update -

 

So, I took the intercooler and all the intake piping completely apart.

 

No holes/leaks anywhere in the intake, as far as I could tell. Turbo compressor shaft spun freely, and I couldn't detect any play at all. So, that's a relief.

 

The only maybe strange thing I noted with the turbo is that it took a fair bit of force to move the wastegate. Is that normal? I could still move it by hand, but it seemed like there was a decently powerful spring holding it in place.

 

Near 6000 RPM, it builds close to full boost, around 10 psi. Now, I definately think something is up with the exhaust. At high RPM, it sounds almost like something is rattling. Looking at the header visually, though, I can't for the life of me tell where it might be leaking.

 

Also, and I don't know if this has anything to do with it, the engine seems to be idling a little higher than normal. Usually it idles around 1400-1500 rpm, and I noticed that it was idling at 1600-1700 RPM. It also sounds a bit different at idle. Hard to describe.

 

Will a muffler/exhaust shop be able to determine the source of the leak? Or, what techniques can I use to try to find an exhaust leak?

Skip- by stuck open, what way would the wastegate lever point? It looks like this:

 

 

 

That's the closed position, right?

If it isn't your waste gate, I'd say it's the up pipe. Right where it mounts to the turbo plate. I had the same problem, car was loud and barely any boost. This happened because my downpipe wasn't secured to the mounting point...on the tranny.

In the pic, I can see that your downpipe isn't mounted to the tranny. I'd say you tore the uppipe right before the weld.

Keep us updated.

My vote is for a cracked header.

It's been a while since I saw your setup

 

so I went out to the

turbo department and fished out a VF11

 

It looks like the arm should move a bit more for total closure of the wastegate.

 

You may want to pull the head pipe back and look

OK- check this out man:

 

Check header for cracks / rust holes and cracks near the weld points. If all looks good:

Take the clip off the wastegate lever and wire the lever tightly to the front of the turbo so the poppet will stay closed for testing. A strong spring would work also. This will at least tell you if it is the problem or not.

If it still won't make boost, I would take your down pipe off and check for a large crack going from wastegate hole to exducer hole. A lot of them are cracked and till work fine, problem is, the cracks get burned open to the point where you get the symptoms you are having.

there may be foreign material blocking the flow of exhaust gasses in the turbo housing

Update: Thanks for all the help!

 

Turns out, the problem was ridiculously simple. One of the nuts securing the header to the head fell out, and the gasket at the head was broken. Huge exhaust leak.

 

It's fixed now, and it is much, MUCH quieter. SICK amounts of power, too. Feels like a different car. Of course, it feels like that since I've been driving it with the 900 of my cc's venting exhaust to the atmosphere for who knows how long.

 

I'm just so pissed at myself I didn't see the missing nut...amazing how it's the little details that get you!

I still suggest mounting that downpipe to the tranny...you can see the point is mounts to. It's right to the left of the CV...the DOJ.

I still suggest mounting that downpipe to the tranny...you can see the point is mounts to. It's right to the left of the CV...the DOJ.

 

I definately will, thanks for the tip! I guess it's the vibrations that twist everything, huh?

might want to add a simple heat shield for the DOJ boot

also

 

simple "U" of 1/2" steel - rad hosed onto the pipe

 

with a 4" x 6" piece of sheet metal

fastened to the other leg of the "U"

 

A bell mouth or better - divorced pipe for the waste gate

down pipe

would also help

Good to see it a was an easy fix. I was banking on it being A.

Well, 300 miles later, I lost a nut on the driver's side now! (before it was passenger side)

 

So, I got the real deal fasteners to get that header on there.

 

Question, though - the stock fastener is like a stud, yet putting another nut on there, after putting some torque on it, the stud just fell out like if the threads were too small. I tried to put it back on and... the threads ARE too small! What gives?

on which issue is the problem?

studs can pull threads out of heads

on which issue is the problem?

studs can pull threads out of heads

 

Yeah, I think I stripped the threads from the head. How do I prevent doing this in the future? For now, I am just gonna put in on there in the other orientation with the correct hardware. (I have the TWE header with the four mounting holes)

exhaust stud threads strip all the time.

heli-coil time. stock headers have to be removed to do this, after that it's really easy to helicoil as there's no access issues. removing the header is annoying.