VonK :: Retired

Does anybody KNOW (not THINK) what the ECU does when I observe the following (stock S4 engine, 93 fuel, 45°F, sea level, all hoses and BPVs healthy, no error codes):

1. On a level road, I hold steady 3,500 RPM in 6th gear for a couple of minutes to allow the intercoolers to cool down.
2. Then, I hit and hold WOT.
3. As the turbos spool up, boost rises rapidly to a peak (i.e. 0.75 atm on this day)
4. Within a second or two, as intake air temperature rises due to compression and intercooler heating, the boost recedes to, and holds at, a lower level (i.e. 0.60 atm) .

Repeated cycles of 2. - 4. result in successively less difference between the peak and lower boost values.

If this is normal behavior, what parameters does the ECU vary to cause the boost to recede at WOT (presumably, to avoid detonation)?

a) Ignition advance?
b) Wastegate position?
c) Both?
d) Others?

At WOT, does the ECU listen and adjust continuously for detonation?

Where can I read up on this?

TIA :-)

Mike O.

Can you log your wastegate freq valve for me during steps 2-4?