RS4 MAF Tuning

Progress with the Nefmoto community 2.7T Stage 2 tune has spurred my curiosity to find out why the results I’m seeing with a Hitachi MAF equipped car are significantly different from two others car that are participating in the tuning project, but are equipped with Bosch S4 MAF sensors.

Bosch MAF vs Hitachi MAF equipped S4's with Nefmoto Community 2.7T STage 2 Tune
Bosch MAF vs Hitachi MAF equipped S4’s with Nefmoto Community 2.7T STage 2 Tune


I don’t have an S4 Bosch MAF on hand, but I do have a Bosch RS4 MAF, which I decided was close enough to try out in order to see if the car behaved, or rather logged, much different than with the S4 Hitachi MAF.

With that end in mind I replaced the stock airbox with a RS4 airbox, the Hitachi MAF for the RS4 MAF, S4 and RS4 accordion hoses were also swapped, and the stock y-pipe was pulled to allow the RS4 accordion to attach to an RS4 y-pipe.

RS4 MAF installed on Audi B5 S4
RS4 Airbox, RS4 MAF & Accordion, RS4 Y-Pipe

After the hardware was swapped and I verified that I was getting a good reading from the sensor using a first draft of the revised tune, I began to look more closely at the tables that needed to be tweaked in the ME7 code.

A few that need to be changed are:


The KFKHFM table is turning out to be one of discovery, I’m needing to adjust this table quite a bit more than I had expected in order to richen up the AFR.