UrQ Dump Valve Construction

[Andrew Finney <afinney@tamsconsultants.com>]

Basen on the very informative dump valve post last winter,
supplemented with Avi's new description of dump valves for the
5000 series here goes my attempt at constructing a dump
valve for the UrQ. Feel free to tell me it will never work and if I
missed something.

Object is to dump excess pressure that acts to stall turbine
during shifts under heavy boost, and possibly to decrease the
lag in the UrQ turbo and maybe (now I'm stretching) to
increase driveability. We need to dump the boost into the line
between the airbox and turbo to avoid dumping metered air into
the atmosphere.

As Avi suggested we braze a nipple to the intercooler (ours are
of course aluminum). Most likely the intercooler outlet as it
has a long neck and lots of area to add an outlet. Then we drill
and tap or braze a fitting to the aluminum neck that goes from
the top of the airbox to the turbo-to-airbox accordian hose. We
can't really cut this hose as it is wire reinforced and tapered at
the ends. Plus it is very expensive (as are most all parts in a
UrQ). 

Now we have an inlet and outlet for the dump valve. Now we
just need some hose ( what diameter?) and the actual valve
(PN 699 0280 142 102 Bosch ) and a vacuum tap to activate
the valve.

Questions: Will this work? Does it seem like a bad idea to
dump the boost directly downstream of the air metering plate?
Where do cars that have this as standard equip dump their
boost? This of course is just a plan. If it sounds good, maybe
I'll give it a try. Thanks. All input welcome.

Andrew Finney
1983 UrQ.