E9X 325i-MSV70 to MSV80 Conversion

The purpose of this procedure is to convert from MSV70 to MSV80. This procedure will be necessary for all 2006 325’s and 330i’s in order to run the Spec E9x tune, courtesy of Epic Motorsports. These Instructions are specifically for the 325i. Instructions for the 330i are here.

The reason for this conversion is to unify and consolidate the ECU calibration, creating parity within the 325, 330 and 328 model range. This way we will have all cars running on MSV80 and one calibration for the entire Spec E9X racing series. This will ensure that there is no perceived and/or actual performance advantage.

1. First thing to do before removing anything, key it on, disconnect the steering lock (ELV) connector. It’s the only connector plugging into the left side of the steering column. Then remove the key and turn it off. Steering lock should stay unlocked now.
2. Disconnect battery
3. Gain access to Ebox (passenger rear corner of engine bay, remove white cover)
4. Disconnect DME connectors and remove DME
5. There are two connectors on the DME, we’ll be working on the connector on the outside, closest to the passenger fender.
6. Disassemble the connector and slide out the harness/pin holders.
7. Gain access to X6005 on the connector side, we’ll be working on the longer connector.

8. Find PIN 26, Yellow Wire. Remove the pin by pressing the small detent on the pin. Find PIN 4 location, it should be open with no wire. Now install the YELLOW wire into PIN 4.
9. Put everything back together and install the MSV80 DME. You’re all done in the EBOX.
10. Remove Air filter box, intake piping to the throttle body, and remove the throttle body.
11. Install the 328i Throttle Body (the MSV80 TBs have plastic butterflies, compared to the MSV70 being metal)
12. The 328i throttle body has a different connector than the 325i/330i throttle body, so there are two options.
Option 1: Use an adapter harness from Condor Speed Shop
Option 2: Get a pigtail for the 328i harness, cut the 325i/330i connector off, and either butt connect or solder wire by wire for all 6 wires. All wire colors are the same except one, it’s ok, just connect them together.

15. Reinstall removed components. When you get to the air filter box, the MSV80 328 Mass air flow sensor has to be installed. To do so, simply remove two T20 Torx screws and the sensor comes off.

16. On the connector for the MAF, remove pin 2, BLUE wire. Either cut it or tape it back, whatever you prefer as it’s no longer needed with the MSV80 DME.
17. Remove CAS module under driver side of dash.

18. Install new/donor CAS, it should be all black. Reinstall removed components.
19. Use new/donor 328i key and turn the vehicle on. If your MSV80 DME came from an auto, you will need to press the clutch AND the brake at the same time to turn it on. This could be coded out in the future if need be.
20. Does the car start? Yay! You’ll notice the cluster will now have different mileage and a dot, ignore it, it’s due to the donor parts.
21. You will possibly need to code your DSC module with the new vin and then perform a DSC calibration.
22. You’re all set!

Courtesy of Jonathan Bowerman at Corsa Technik and Curtis Buxton.