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Re: TAP Chip & WG Spring in '90 200Q

Michael Callaghan wrote:

> 1) The wastegate spring, once installed, caused the engine to shut
> down completely above 2000 RPM. The mechanic at Eurosport said that it
> would take roughly two hours to tweak the wastegate to make it work
> properly. They said that it's the same problem they had with a TAP
> upgrade they installed in an S4 recently. I was under the impression
> that this was a plug-and-play operation.

Hmm, indeed it was for me back in '93.
> 2) The spring is both longer, and has a larger diameter than the stock
> spring. Is this correct<...>?

> 3) With just the chip installed (the spring is in the glove box),
> performance is no better than stock, and perhaps a bit worse. Maximum
> turbo boost (according to the dashboard digital guage) is only 1.2
> bar. I had been seeing 1.4 bar previous to the chip. So the question
> here is: What exactly does the chip do?

The TAP chip uses a Zener and a ballast resistor circuit to fool the CPU
into thinking that the boost is at a safe level (below 1.2 bar).
You_will_always see this boost on the OEM gauge, even though in reality
you'll be running 1.8 to 2.0.

Ned's (Intended Acceleration) ECU mod does not have this problem.

An analogue boost gauge is a must have with a TAP chip! VDO sells
a few types. I bought mine from JCWhitney for 15bux, goes from 30" Hg
negative to 20psi positive.

Also replace your WG cap with the one from an Auto FWD 200T/5000cs.
Unlike our WG, the automatic one is adjustable. Drill the top plug out
and adjust the 6mm hex screw so that you'd not exceed 14psi under WOT on
a cold damp day. Remember, your car is a '90 200 and has a high
compression MC engine with a smaller, faster spooling K24 turbo. Don't
overrev the turbo and don't overlean the mixture by running too high a
boost on this very sensitive engine of yours.

When I installed the TAP chip on mine, I was running in excess of 22psi
of boost and could hear pinging in a hot track day in the Summer. Mucho
dangerous! Fortunately Scott (QSHIPQ/PDQSHIP) warned me about the likely
con$$$equences of running such high boost. Mind you, mine is a
bullet-proof early '89 with a low compression MC engine and a larger but
slower spooling K26 turbo.
See an excellent post by PDQSHIP in the archives:  I think it's named
"supersonic turbos" or some such.

Also a fuel to air (Lambda) gauge helps to prevent overleaning the
mixture. They are available commercially from a number of vendors. 
I designed and built my own coz I couldn't find one in a round 52mm case
as to match my existing boost gauge.

I have both gauges installed in the LF corner of my torpedo. Wouldn't
run a chipped car without either of them.

Igor Kessel
'89 200TQ -- 18psi (TAP)
'98 A4TQ -- FINALLY!
Philadelphia, PA