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Forced Induction Upgrades

From MS4X Wiki

Summary of forced induction upgrades

2048kg/h MAF Sensor switch

Inside the MS42s and MS43s code there is a artificial mass airflow limit of 1024kg/h. Artificial because the it's leftshifted four times reducing it from the real limit to 16384kg/h.

MS43 MAF Sensor Handling in IDA
  • MS430037: 0x3D719 & 0x3D73D
  • MS430055: 0x413A3 & 0x413C7
  • MS430056: 0x3D8A3 & 0x3D8C7
  • MS430064: 0x3E0E5 & 0x3E109
  • MS430066: 0x3B4C3 & 0x3B4E7
  • MS430069: 0x3B4C3 & 0x3B4E7

Audi RS4 MAF Sensor Conversion

A cheap alternative for the HPX PMAS MAF is manufactured by Bosch with the part number 0 280 218 067 (or 0 986 280 219) and is installed on the Audi (R)S4 B5's 2.7 V6 biturbo engine and is able to measure upto 1800kg/h.


The MAF sensor module comes preinstalled in a 3.5 inch housing and has a 5 pin connector (Audi part number 1J0973775A) with the following pinout: Pin 1 - IAT sensor output (not used) Pin 2 - voltage input 12V (red?) Pin 3 - common ground (black) Pin 4 - voltage input 5V (brown/white) Pin 5 - MAF sensor output (yellow) The IAT output on pin 1 can be connected to an aftermarket logging device to monitor the intake air temperature before compression, or in case you leave it unconnected, make sure to seal the pin in the plug, to prevent the maf from corroding like this.

Pins 2, 3 and 5 should be self explaining, you can just connect them to the OEM MAF wires, or create a new 4-wire loom and run it to the cable distribution box located under the intake manifold.

Pin 4 need a solid 5.00 volts supplyvoltage, as this is the reference for the MAF output signal. This is absolutly crucial for the MAF to work properly!

The MS43 has two integrated 5V outputs, one for the electronic accelerator pedal and one for the electronic throttlebody, which you will preferly use, because you can tap into the wire right in the distribution box.

By the way, this is pin 7 at the middle ECU connector (X60003) for the voltage U_DKG according to the manual (brown/white, 0.5mm²) If anybody is concerned about the MAF drawing too much current, during operation it only needs 1,1mA


Now that you have the connection from the MAF to the ECU, the next part is applying the MAF hack (512k file) and editing the sensor definition (64k file)

You have two options to double the MAF limit: First is to do it manually with a HEX editor and changing the bytes 0x3D8A3 and 0x3D8C7 from "4E" (1024kg/h) to "3E" (2048kg/h) and double the conversion in the Tuner Pro MAF table to "0.03125*X" Second is downloading RomRaider and the MS43 definition .XML file, flick the switch under the "Forced Induction" section and use the special MAF table right next to it. Either way you have to recalculate the four checksums in the 512k file, even if you use the CHK5/EWS delete File from Daniel, as this only disables the fifth checksum in the 64k file.

In addition to that, you need to (suppress the MAF DTCs with zeroing "C_ABC_INC_MAF" and "C_ABC_INC_MAF_MON",) set "C_MAF_KGH_R_LS_MES_MAX" to 1800kg/h and C_MAF_MAX to 1389kg/h (the highest value possible for this constant).


Discussion on e46fanatics.com

Using rear lambdaprobe inputs for WBO2 or MAP

Several people remove their engines rear lambdaprobes and just leave the ECU inputs unused.

After taking a closer look at those two input in INPA, we see that they are rated for voltages from 0V to 5V with an accuracy of 4.8828125mV.

Why not using those otherwise wasted inputs for something handy like integrating a manifold absolute pressure (MAP) sensor or wideband lambdaprope?!

Both, the MS42 and MS43 share the same pinout at connector X60002, which is the second connector from the left looking at the ECU top down.

MS4x Rear Lambda Inputs 1.PNG


As we you see in the schematics, both lambda probes have four connections:

Lambdaprobe X60002

Bank 1 / 2

Description
Pin 1 - U_HR Ignition switched +12V for heater element
Pin 2 Pin 07 / Pin 19 T_LHH1/2 PWMed ground for heater element
Pin 3 Pin 22 / Pin 24 M_LSH1/2 Sensor ground
Pin 4 Pin 16 / Pin 18 A_LSH1/2 Sensor inputvoltage

The minimal setup would be using only the two inputs at pins 16 and 18 and feed a sensor return voltage into them.

But there's also a +12V supply switched by ignition and a ground connection. We can perfectly use those for creating +5V to power the MAP sensor by using a LM7805.

For the

Attention: Never use the PWM ground as the ECU uses this to control the heater element inside the lambdaprobe! Also keep in mind, that the signal ground was never rated for high currents, like a heater element.