All,

I don't know much about the boost control system but I would like to understand this particular piece since it has proven problematic lately. The "F" shaped metal fitting seems to like to blow out of it's home under boost. When this happens the PFC set limits for boost are no longer achieved and the turbos spin as fast and the physically can allowing for "creep" well above targeted boost, to the point of fuel cut (PFC target + 2 psi)!. It appears to be the location of the restrictor pill (seen here http://robrobinette.com/boost_note.htm) but there were not "pills" inside. Is the "F" fitting the restrictor itself?

The metal tube that slides into the turbo has no real way to grip and secure itself. It just slides in.. and out!. Has anyone ever thought of a way to secure this fitting? Tried to expand the tube a little to make it fit more snug, but that did hold for more than a day.

 

i would think a little bit of carefully applied silicone would keep that "F" fitting in their.

and you are correct those 2 lines (wastegate, and turbo pre-control) have the pills in them.

i believe blowing them off would cause your wastegate not to open and thus have mega overboosting. i think creep is defined as gaining boost while the wastegate is fully open.

 

So if there are none, then someone took them out. Is that I good thing for performance given my mods (turbo back exhaust, high flow cat, intake, fuel pump/injectors, PFC) or should I get them back in there? Going to search this.

 

If I understood correctly, that hose is the wastegate hose. So if your wastegate isn't working, boost control will be compromised. Check the FAQ for the link to the turbo troubleshooting website.

 

Such a thread would be a little broad considering I know the cause of the problem and the general idea how to fix it. Just looking to figure out how to secure the fitting and whether or not I should replace the missing "pills".

 

What you are getting is not creep (which is caused by the exhaust gas flow exceeding the wastegate flow capacity) but uncontrolled boost cause by the wastegate remaining shut. I would not drive the car like this - fuel cut may not save you.

I'm really not sure how to secure the fitting though - JB Weld or the like will not handle the temperatures here. And this fitting, as far as I am aware, can not be ordered separately from the turbo assembly.

 

Thanks. RotorRyan mentioned the difference between creep and my problem. My fuel system can handle all the boost the stock twins can dish out so I am not too worried. I am actually more worried about the fuel cut making a lean spot. Setting the PFC to high boost would prevent the fuel cut if this pops off again, but for track purposes I prefer to run low boost to keep temps down.

 

Yes - but you would boost until your engine blew. I'm not sure what you mean about your fuel system being able to keep up. How are you going to tune for 25 psi?

 

I have a cat so the exhaust is too restrictive to have it boost creep that high. Creep aside, stock twins can't put out more than 17 psi (i think)

 

Since your wastegate is not evening opening when this fitting pops off it is irrelevant what is downstream of it.

The stock twins can put more than ~15 psi efficiently - you can overspool them significantly more than that.

With a stuck wastegate and no fuel cut you are guaranteed to blow your engine if you keep your foot on the throttle.

 

I must have ran the car for months with this piece blown out of place. Boost never peaked over 1.15 kg/cm2 (~16.36psi) on the PFC.

 

That's crazy boost. I would barely trust myself to drive down the street like that. I would start with the JB weld since something is better than nothing, but then source a replacement. It might require removing the turbos and taking off the compressor housing to change it.

Or remove it to tap and install a more secure connection.

 

I would like to avoid taking out the compressor to tap and thread. I've thought about it but it's a lot of work.

I was thinking of creating some kind of wedge to go between the frame of the car and the back of the fitting.

 

Since the PFC is reading from the MAP sensor, the stock map sensor is a 2 bar sensor. i.e. it only sees up to just below 17 PSI (even if you might generate more).

Just use some JBWeld on it.

 

Oh damn! I'm going to weld this asap. Didn't realize the peaks I was seeing this whole time could have been off.

 

The autosports site would have told you which line it was and what it does.

 

Ok, so I just slathered on some JB Weld. I hope it holds. Me being a total nOOB, I didn't even realize JB weld is an epoxy (thought it was a weld) hahaha.

 

Yeah, but Howard Coleman would be so proud of you for doing it!

Dave

 

Just duct tape it, that fixes everything... ok maybe not.

 

Looks like JB Weld has higher temperature tolerances than I thought - 500F constant and 600F for short periods:

http://www.jbweld.net/faq.php

Anybody know what temperatures that part of the turbos sees?

 

EGT's can be around 1400F but that is right out of a cylinder (measured on my Subaru). Also, the fitting goes on the cooler (air) side of the compressor.

 

if you are board. you can crimp it like the factory did. remove the upper section, vise grips and a tappered peice of meatel(maybe the end of a gear puller or sweging tool). putting the tappered inside and putting the vise grips on the tappered peice and the outsie end of the barb. basically flaring the inside of the barb inside the intake track. doing this along with the jb weld worked for me

 

I'm sorry, I don't follow.

 

Actually, flaring the end slightly and then pressing it in is a really good idea. You can find pipe flaring tools cheaply, e.g.,

http://www.drillspot.com/products/27...e_Flaring_Tool

 

I flared it a little with a screwdriver and a rubber hammer before reinserting the fitting with the jb weld. It was a bitch to get back in, very tight fit. I don't think it will be coming out again. Thanks all.