Did GM ever correct the stock "y" hose the right size restrictor

[DonnieShort]

Was curious because I was going to get one from our local GM parts guy and remembered some problems with the restrictor size and would like to know if they have it straightened out now. Thanks!!

 

[OKTurbo]

That's kinda a crap shoot....it depends on how long it's been sitting on the shelf.

If I remember correctly, the orifice should be .050". The bad ones were .026" dia.

I used a guitar string (used calipers to check dia.) to make sure it was the correct size. And yes, I have rec'd the wrong one, but it's been a couple of years ago.

John

 

[chris 6]

would the smaller hole cause over boost?

 

[OKTurbo]

Yes...the smaller orifice causes overboost. On my car, I had the wastegate rod as loose as it would go and still keep the wg puck closed. Even like that, the boost would shoot up to 18 psi +.

I couldn't figure it out. It was a brand new part from GM....I kept looking for other things until I came across this problem on the gnttype.org mailing list archives. Luckily I saved the old "Y"....plugged in the old "Y" and VOILA!....problem solved.

A friend was having the same problem after he bought his 87T. We took out the "Y" and it was the wrong one. On his, we used a torch tip cleaner to ream it out to .050"....worked wonders.

John

 

[chris 6]

thanks john

 

[Two Lane]

www.johnsperformance.com has the correct-sized orifices in their Y-lines.

HTH

 

[S10xGN]

I had to re-drill the orifice on mine to 0.050", it came at 0.030". That small amount caused my new engine to boost 20+ at 1/4 throttle!