Hi!

I have an interesting find to share.
Here is a datalog of MAF voltage and boost vs rpm.
Both third gear same conditions, above is NEW BOSCH and bellow is the New Pierburg factory replacement.
What is interesting is the distinctive BOSCH voltage drop between 5400 and 5600rpm. It drops from 4.7 to 3.9V which causes a lean flatspot.
The Pierburg Maf doesn't seem to suffer at the same conditions. What you see is the MAF sensor output signal. The signal is then clamped at 4.6V with AEM piggyback but that doesn't matter in this case.


My setup is w202 c200 kompressor (me2.1) 220mm crank pulley and MAF relocation. Max boost in higher gears is 0.82bar.


It is obvious that the sensors have a different design but should both measure flow as factory specified.

It is obvious from the log that the Pierburg sensor is less sensitive which is seen by smaller fluctuations.

Since the pressure doesen't decrease, the voltage shouldn't eather.

I have a feelling that placing the factory BOSCH MAF closer to the intake manifold causes it to be influenced by induction resonance and reverse flow.
Because of the smaller sensitivity of the Pierburg it's reading isn't compromised.

I have yet to confirm my theory by moving the MAF back to the factory position.

What fixes the lower rev flatspot might just causse one at higher revs...