mrsteve

I've seen several posts to the effect of "my newly chipped car's
performance seems to be worsening over time", and had a thought
on this.

Having previously owned a highly modified Mitsubishi Eclipse GSX turbo,
I have experienced a similar situation with regards to the ECU detecting
knock when boost was dialed high, or it was extremely hot outside
(can accelerate detonation). There was a peitzo (sp?) electric
microphone "listening" in the engine block precisely for this. The ECU's
response to detonation was to back off on the ignition timing, and other
engine parameters to lessen/eliminate these occurrences which ultimately
affected performance for the worse.

Given the S4's boost is controlled by the ECU, it may very well be doing
the same kind of thing (e.g. backing off boost, etc.) when the car knocks
upon installation of a new chip *until* the ECU "adapts" to its application
(it is an adapting ECU, isn't it?). I recall the Mits. could take well over a
tank full of gas to "recover" to optimal when this scenario takes place,
though I don't know how persistent this problem has been with S4 cars.
If you didn't want to wait that long (e.g. race day coming up the next day),
you'd pull the battery cable to reset the ECU. BTW, it had an adaptive ECU
and would take 10-15 minutes to re-learn things.

Just a thought ...

Regards,
Steve