Well it is, but we discovered here and at nefmoto through people who spent hours watching flow execution that the MAF is the true source of load calculation in a motronic system.
Think of it like having CIS or CIS-E, but no airflow meter. What kind of crap is that? How would it ever work?
I have a UNI 630 tune scaled for a 2.75" ID housing (TT housing or VR6) with an OEM AWP sensor. It works phenomenal, and the car ran 100% garbage with no MAF.
It made power, but it had so much in the way of hesitation and misfires that it took so long for the power to come on it was essentially worhtless.
Now the car is so smooth and it absolutely rips into boost the boost builds faster and harder, it's smoother and no hesitation.
What does a MAF do? Determines the MASS of an AIRFLOW. Without an accurate measurement of the charge, or mass of the flow, you are guessing and adding/subtracting fuel here/there afte the fact, which is AFTER the fact and causes hesitations, light misses, a slow climbing tach, flatspots..... etc. etc.
DougLoBlue gained 50whp plugging in his MAF on maestro.
I can tell you running my lil 3076 @ 18psi now with a MAF, it feels like it gained about something similar powerwise.
Ask UNi if your tune was scaled for a MAF. I think UNI maxes with an S4 MAF or 3" housing anyways, they don't offer a file with scaling for a 4" MAF if I recall.
However, until you overrun the MAF, you need it.
My understanding? Timing is extremely load dependant. My timing values bounced all over at idle, add a MAF? Theyre very very stable now. The misfires associated with that timing bounce? GONE! Same at part throttle.
Mafless rev it in neutral hold at 3k. Don't move foot at all.... notice small oscillations
MAF rev it in neutral hold at 3k dont move foot at all... VERY steady, almost NO oscillations.
Something is happening there, and that is just neutral.
Historically look at bosch. You had L-Jet, and D-jet. Or luft jetronic, and druch jetronic. 1967-1979 or so. My 1975 914 has a Luft-jetronic. Luft, air mass. Druck Jetronic, or pressure jetronic.
Bosch figured out over the years, you truly need BOTH of these to accurately control an engine, have it make big smooth power and run great at part throttle. WIth a turbo car, your asking for a serious amount of resolution to go from -HG to +22psi, and how do you know the actual MASS or lb/m the compressor is pushing in? A maf.