RE: Audi 200 Turbo boost control functions

[Aleksander Mierzwa <alex@matrix.com.pl>]

Chris, there are many modifications gurus on this list who will probably
answer you, but here is my $0.02:

The wastegate operation is controlled by the computer module by means of
the three-way vacuum switch located on the firewall near the ignition
coil. Additionally, the computer is supposed to cut the fuel pump if the
boost goes above 1.5 bar. Yes, there is a knock sensor and from what
I've heard, the engine is supposed to knock also when using full
throttle at low rpms. But if it is knock sensor that is causing your
problem, the ignition fault lamp should illuminate and you can pull the
codes from the computer to check what happened. The differential is not
a problem, but the autobox is operating at it's limits already with
stock engine configuration. I was considering chipping my 87 5K too, but
on second thought I don't have spare $1000 to rebuild the gearbox. If
you want to do this, I would recommend using synthetic ATF and
installing an external oil-to-air ATF cooler, since this tiny stock
oil-to-water heat exchanger doesn't work too well and you wouldn't like
your autobox to overheat while you're already putting too much torque on
it.

						Alex



	>Car is 1987 mechanically injected 200 turbo, 2 WD. I am
wondering if the 
	>only boost control is via the wastegate spring and manifold
pressure.The 
	>reason I am curious is that the car displays excellent part
(half to two 
	>thirds) throttle acceleration,but on full throttle,there is a
noticeable 
	>drop in acceleration.Lifting off will often produce _better_
acceleration.

	>Is there a knock sensor that may be coming into play,although I
would 
	>expect this to kick in around maximum torque RPM, not just on
full 
	>throttle.What does the throttle switch do?
	[...]
	>BTW,any idea how much extra torque the auto box / differential
will stand 
	>without becoming unreliable?