Blowing this hose causes boost creep... Fix?
05-03-09, 09:04 PM
#1
Blowing this hose causes boost creep... Fix?
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.
05-03-09, 10:07 PM
#2
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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.
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.
05-03-09, 10:13 PM
#3
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.
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.
05-03-09, 11:49 PM
#6
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.
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.
05-03-09, 11:55 PM
#7
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.
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.
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05-04-09, 12:19 AM
#10
Creep aside, stock twins can't put out more than 17 psi (i think)
With a stuck wastegate and no fuel cut you are guaranteed to blow your engine if you keep your foot on the throttle.
05-04-09, 05:19 AM
#12
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.
Or remove it to tap and install a more secure connection.
05-04-09, 08:30 AM
#13
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.
Or remove it to tap and install a more secure connection.
I was thinking of creating some kind of wedge to go between the frame of the car and the back of the fitting.
05-04-09, 12:49 PM
#20
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?
http://www.jbweld.net/faq.php
Anybody know what temperatures that part of the turbos sees?
05-04-09, 12:58 PM
#21
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?
http://www.jbweld.net/faq.php
Anybody know what temperatures that part of the turbos sees?
05-04-09, 02:19 PM
#22
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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
05-04-09, 02:23 PM
#23
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
05-04-09, 02:29 PM
#24
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
http://www.drillspot.com/products/27...e_Flaring_Tool
05-04-09, 02:45 PM
#25
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
http://www.drillspot.com/products/27...e_Flaring_Tool