[s-cars] Waste gate creep

[CaptMagu at aol.com]

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Rich

In my experience with slightly(tongue firmly held in cheek) larger than stock
turbos, the phenomenom known as WG creep has a tendency to rear its ugly
head. Actually, the size of the turbo has nothing to do with creep.

Julian Edgar accomplished a whole bunch of mods on his otherwise stock urS4
to enhance its performance. He wanted to maintain the stock boost level(oh
the shame!) but enhance the spool-up/boost threshold. Each of his mods were
tested against his stock performance and he gained a lot over stock in his
quest. One of his other series of mods involved the rather mysterious, cult
status, oft theorized, phenommenom called, tah dah---- NEGATIVE BOOST. But I
diverge from the subject at hand. Creeeeeep! It happens folks, deal with it!

My solution is a top of WG pressurized electronic boost controller and a very
stiff WG spring. My controller of choice is the Apexi AVC Type R. It has the
ability to learn my CRB 6 speed's gear ratios which allows me to establish
custom boost profiles for each gear. Even though I have a wide hard first
gear I still take it easy on my tranny by limiting boost in first and second.
Some on this list have been critical of secondary devices used to control
boost. I have found them to be very helpful in lowering my boost threshold
while still retaining many of the ECU override protections. It should be
noted that I am limiting the boost more than controlling it with the Apexi. I
run my boost at 22 psi for everyday driving and limit the high boost to 26
psi.

Another related issue for my car has been WG float. This particular problem
comes from using a significantly larger(Happersize tm.) turbo and still using
the RS2 EM. The pre-turbine pressure from using this larger turbo can build
to a very high figure. The float manifests itself as a 2-4 psi boost pressure
pulse that can be eliminated with a higher WG spring preload.

So, to summarize, I use electronic boost control with a Happersized WG spring
to accomplish the same thing that Julian handled with a simple DIY solution.
Go for it. BTW, my car comes on to full boost at 3100 rpm with a TA34/T04E 54
trim Garrett turbo.

Hap, feelin the boost in Everboost, Maguire