maaliish

Based on my VAG-COM, when BM is first turned on, ECU is requesting about 2300mbars and using around 95-100% duty cycle while building boost which spikes to about 2500mbar and then duty cycle drops to about 80% with boost being held at a little above 2300mbar. Held and requested boost figures are very close. After driving with the same settings for a few weeks I noticed that held duty cycle is now at 60-70% with the same 2300mbars requested and delivered. This leads me to beleive that ECU simply adapted to the BM and requests less boost from N75 to accomodate for the BM. Oh, and that spike is now a little lower (2400-2450 mbars) but like I said, it holds at the same as when BM was first turned on.

Any thoughts?

maaliish

how much? (mbar wise). I know it depends on the number of turns (I think I got it cranked up to 6-6.5) but assuming a very conservative tune, what should the difference between requested and held be?

TTschwing

Is pretty much the norm with the APR set-up. Normal taper. I think this is more programming and RPM based rather than solely determined by Boost pressure. At various times with my car i've achieved way more boost than requested would indicate. I think this is largely determined by cooling issues....If the ECU reads cool temps, it allows more headroom on all the parameters (Timing, Boost, etc.). You really can't duplicate conditions Ever, due to the mumber of sensors, different temps, Barometric pressure, humidity etc. There are Too many ECU inputs to ever expect consistant performance. It is always adjusting and adapting to the information it is receiving.

I'd turn the BM down a bit. You may be up in the unregulated area, deffering controls to other inputs. It's like chasing your tail...there is a sweet spot and beyond that results in some flaky behavior...

maaliish

Thanks Steve. I'll turn it down 1/2 turn and see what happens.