Hybrid turbo upgrade selection & general tuning question

[RETed]

Overboost fuel-cut has been programmed in every stock ECU at approximately 1psi over stock levels.
This basically means just a little higher boost will trigger it.

Some stock S5's with stock ECU's have never been known to hit overboost fuel-cut even when obviously going way over stock boost levels.
(S4's, OTOH, will always hit overboost fuel cut at ~6.5psi.)
No FCD (fuel-cut defensor) or any other electronics that's molesting the stock boost sensor signal was obviously found...
We don't know why this is the case.
We can't seem to find a pattern with ECU part numbers either.
Some claim that if the car hits the overboost fuel-cut enough, it somehow disables the stock programming - I can't confirm nor deny any of this.
FCD's are cheap (i.e. Racing Beat), so it's really no excuse not to use one.
There's even a DYI version posted on the INet if you're good at handling electronics.


-Ted