Some Boost Controller Info

[CM1022@aol.com]

The Greddy, HKS, SARD, Apexi, Blitz, etc. are all pretty much the same.  They
provide a more active control over the wastegate, but because of their
electronic nature I don't know if it will work with an Ur Q.  Did the Ur-Q
have an electronic timing valve?  This valve, found on most later models of
turbo kraut cars, is a simple device the modulates between either positive
(boost) or negative (vacuum) pressure on top of the wastegate to more actively
control it.  This is esentially how an electronic controller wires- right into
the electronic timing valve.  I have seen pictures of the wastegate on the Ur,
and it seems that maybe it is just spring activated?

Whatever the case, you might want to avoid the "fuzzy logic" controllers like
the Greddy and HKS stuff, which I know have problems and take time to fully
program.  Again, some very knowledgable people have told me the only
difference in units is the color- pick one.  

Another problem with these electronic controllers is boost hunting.  Most
stock wastegate's are actually designed to leak, and the only solution is
getting a new wastegate- one which is more agressive and performance
orientied.  They can be relatively inexpensive- turbonetics has some decent
prices.  The point is that the stock wastegate is inaccurate- leaking way too
much, and the controller has problems with this, sometimes literally searching
for a stable boost pressure.  

Greddy offers the simple Profec B, which isn't fuzzy logic but still requires
a new wastegate in my opinion.  I would choose it for the simple reason that
Greddy makes a steering wheel button activator- a great feature to use when
powering into or out of a corner (switching between high and low boost
settings).  

And then there is the manual boost controller- which is pretty foolproof but
limited.  Everyone sells one- you can even make one.  It is a knob that has
vacuum lines hooked up to it that goes between the wastegates vacuum/boost
input, and the timing valve.  

Chris Morlock

86 951
83 928S
81 928
81 931
70 BMW 2800 CS
and a Harley in there somewhere at sometime