Wastegate hoses and fittings.

[Recklessrob]

This is something frequently overlooked and
mis-installed, So I made a simple diagram that
you can download for reference.
....also because 1turbo6 requested it. :prayer:

[sun dog]

Nice tech work!  :prayer:
 
When I got my second GN I spotted they had the lines backwards on the "y".

[Turbogn86]

i have looked for that pic amany of time, but i have it memorized now... lol   only took me 4 yrs to memorize it.

[Recklessrob]

I had a diagrm of it saved somewhere. But I couldn't
find it, so I made one...

[dennisL]

Forgive my ignorance, but I don't see a link to the diagram.  (I suspect it went away over time, but this is the Knowledge Base section;  It should always be here.)

[gnonyx]

I don'y know if Recklessrob was going to post the same photo as I did, but here it is.
 

[Just a Six?]

All mine are Grey? With the .050 orfice Black ones how will that change the boost?
Lower? Higher? 

[Steve Wood]

Mine were originally gray.  The smaller hole causes higher boost by my logic.  As I recall, which is not all that good these days, the smaller holed versions were replacements sold over the counter and caused too much boost on a stock car....the originals were somewhere between .046" to .050", I think.

[earlbrown]

Odd. For some reason I was thinking the restrictor went on the solenoid side. My screwy logic was so that it couldn't dump too much wastegate signal.

I guess I need to go flip mine around and CAREFULLY see what it does to boost.

[Steve Wood]

LOL  restrictor goes to the compressor port

[dennisL]

I was looking at some old files and found one regarding the wastegate "Y" hose.  Thought it should be here instead of on my Windows 98 Pentium II computer.   


Since GM made Y-hoses with two different size orifices, you can determine the correct one by it's color (black tee is good, grey not good) but the best way is to strip the insulation from one of the wires in 14-2 Romex electrical wire.  Push the solid conductor 14 awg wire into the straight side of the "Y" fitting.  It should pass through.  If it doesn't, the orifice is the wrong size and should be replaced.

[Steve Wood]

Not too sure about that, Dennis. I have heard that more than once, but, both my cars came with gray "Y"s and they were the correct orifice size

The orifice size on the originals was 0.045-0.050"

Some, if not all, of the replacements were smaller...some where around 0.035" which caused overboost when aiming for the stock boost levels with a working wastegate solenoid.

[Steve Wood]

Googling found this   http://www.turbobuick.com/forums/threads/wastegate-y-restrictor-orifice.344019/

Not sure if John every bought one of these new, but, if anything, he got it backwards this time 

[dennisL]

I only included the "black/grey" thing because it was in the drawing from a previous post.  Back in 89/90 when the smaller holes were discovered, we didn't pay much attention to the color but I did keep a foot of 14 awg solid wire in my tool box to check the fittings.

[Turbodave]

I only included the "black/grey" thing because it was in the drawing from a previous post.  Back in 89/90 when the smaller holes were discovered, we didn't pay much attention to the color but I did keep a foot of 14 awg solid wire in my tool box to check the fittings.

I'm not sure where this black/gray thing came from.  I've got two GN's and my 87 still has its original grey Y in place.  I also still have the original gray Y from my 86 (I'm the original owner) here also.  NEVER seen a GN with a black Y.  Don't know what color the TTA's originally came with, but I do know the GN's (at least the 86/87's) came with gray.