UrQ Blowoff Valve

[Andrew Finney <afinney@tamsconsultants.com>]

Date: Wed, 12 Nov 1997 06:18:48 -0500 (EST)
From: QSHIPQ@aol.com
Subject: Re: UrQ Dump valve

In a message dated 97-11-12 00:59:44 EST, someone writes:
> If your running a stock turbo the Bosch valve is barely
adaquate.....  On 
> my car I was Blowing the valve open at 9PSI of boost (Were
talking 
> DENISTY Here.......)  I had to go to a HKS race valve to get
it to 
> work....
  >>
?
Scott replies>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Sounds like someone put the valve on wrong, high pressure
goes 90 degrees to
Manifold nipple, low pressure (turbo inlet) opposite.  Reversing
the valve
(easy to do the oriface diam is the same) will allow the valve to
"blow" open
sooner, more specifically, prevents the valve from closing soon
enough.  Air
DENSITY has nothing to do with bypass valves blowing open,
or their
effectiveness to FLOW and PSI.  The valve could care less if
the charge air
is -40 degrees or 400 degrees, it "blows" open at x psi.  The
stock k24 is
good to around 14-15psi (btdt & Ned tech tip), the sport q uses
as stiffer
spring and is good for boost levels in the 18-19psi range (btdt
& Beckius).
 There are direct replacement all aluminum ones direct
replacements available
that are good to 24psi (btdt).  
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Scott, as always, an informative post. The only question I still
have, that no one has answered, is it bad to dump the boost
close to the air plate? There is no easy way to create a nipple
to receive the dump in the line between the air flow plate and
the turbo inlet unless 1) you tap the aluminum cover attached
to the top of the air box and flow plate or 2) you add a tubular
spacer, maybe from Spearco, into the line and tap this. I don't
want to start cutting the accordian hose between the air box
and the turbo inlet 3) tap the small metal right angle "hose"
that connects the accordian hose with the turbo inlet. Anyone
have any thoughts here? 

As for the other end, I'm still thinking of tapping the long outlet
neck of the aluminum intercooler. Any thoughts there. Any
"best ways" to create an effective leak proof tap? What diamter
are we taling about here? Is any of this worth it for a UrQ with a
k26 and TAP chip? Thanks.

Andrew Finney.
1983 UrQ.