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EGT Turbo Gauges,
In message <349B523C.7F32@sprintmail.com> Mike Zamikhovsky writes:
> The sad point in EGT setup for our beloved cars is that the data that we
> get is only academic. We can't easely readjust our fule and ignition
> systemst to compensate for lean mixture. Yes some of us modify and
> upgrade fule destributors and wormup regulators but we still don't get
> accurate performance. I once saw 10V Turbo using MB 8 cylinder fule
> destributor. It ran rich at idle. There is no win with CIS. Installing it
> and learning to interprite info is good experence.
The main problem is a lack of understanding of how the ECU intervenes _all_ the
time. All of its interventions are against a background of basic assumptions
about the engine design to which it was originally matched - change the cam or
gas-flow the head and you _MUST_ change the ECU. Unfortunately, most (if not
all) of the 'chippers' restrict themselves to changing boost and timing tables,
and one or two on this list have shown that this is not enough. Some of the
ECU's actions (especially but not only fuel frequency valve operations) are the
result of complex (hundreds of lines of code) calculations in the ECU using all
sorts of inputs - even including battery voltage.
On a modern-ish engine (MAC11B and later) there is almost nothing you can do
that will not unbalance the engine in some way. Even raising the boost level
by zapping the tables will almost certainly cause the engine to run lean at
high boost because of mechanical limits in the air mass sensor.
Committee Member, UK Audi [ur-]quattro Owners Club