I figured this project was significant/interesting enough to warrant it's own thread. This isn't meant to be a DIY guide but I hope it's helpful as a reference. For more info on this build you can Google "Evan's E61."
Some of you might be familiar with my build, back in 2015 I started down the path of a RWD conversion when my front drivetrain was having a hard time handling the ~550awhp at my lowered ride height. For the sake of reliability and simplicity a RWD conversion seemed like a smart move. I loved the grip and poor weather capability of the AWD system but it was a ticking time bomb and I got tired of driving gingerly as to not hard the drivetrain.
The process started with pulling the front driveshaft, axles, disconnecting the TC actuator, and some coding. It was as step in the right direction but not a real solution. A manual swap was always on the radar so I went ahead and collected a RWD manual trans, all the necessary components for the retrofit, and upgraded the drivetrain to M5 everything with an MFactory SMFW, Spec Stage 3 clutch, upgraded trans and diff mounts. This setup necessitated a custom M5 dirveshaft and custom trans support. I also relocated the DSC pump and swapped the module to a unit from a 528i since they were compatible with 535is.
I never found success integrating the DSC pump into the car, there were some issues with the VIN and region since there were never RWD wagons in the US, or so we thought. The wagon was operational but DSC/ABS was in a default and non-functioning state since communication was broken between the systems.
My front subframe was the steel AWD unit and I hacked up my old axles, removed the outer CV cup with the splines, and used it with the 36mm axle nut to hold my spindles together. Not ideal but it worked.
The xi steering rack was a bit slow and I found myself annoyed when I would have to regrip the wheel during fairly standard 90 degree corners, it was obvious the steering wasn't up to par with the rest of the wagon.
Enter the M5 steering rack retrofit. Of course the xi subframe has a completely different architecture to accommodate the axles so to swap the AWD steering rack to an M5 unit required swapping the subframe and nearly all components which was everything minus the passenger side engine mount. lol
Here is a list of components I collected for the subframe swap
- Aluminum RWD Subframe
- M5 Steering Rack
- M6 Convertible Sway bar (thicker than M5 and M6 Coupe)
- KW V1 (RWD E61 Fitment, special order from Germany)
- 535i Power Steering Lines
- Engine Supports R/L
- Driverside Engine Mount
- RWD Spindles
- RWD Hubs
- M5 Control Arms
- End Links and brackets
- RWD steering shaft and firewall grommet
...that's it!
The main benefit of this conversion is the M5 steering rack but a nice bonus is the increased amount of room the RWD subframe offers, if you wrench a lot like I do that it's a significant improvement. For those of you who have never worked on AWD N54 cars consider yourself lucky, they are a pain.
The other bonus is the weight savings. Comparing the assembled AWD subframe to the aluminum RWD subframe, ~55lbs is saved.
AWD Subframe = 43 lbs
RWD Subframe = 20 lbs
AWD Spindles = 38 lbs
RWD Spindles = 12 lbs
-26 lbs of unsprung weight is a nice!
Adding this weight savings to what I have already saved with the AT-MT swap and deleting the other front drivetrain means the wagon has shaved 200+ lbs with the conversions although was added back with the beefier M5 components.
On to the photos, the first few are a recap of other RWD related parts which were installed.
M5 drivetrain
RWD manual trans vs AWD auto trans
Stock xi open diff vs M5 diff, M5 heatsink needed to be modded to fit wagon.
AWD oil pan up top vs RWD oil pan bottom
RWD configured motor going in
Motor in
Some of you might be familiar with my build, back in 2015 I started down the path of a RWD conversion when my front drivetrain was having a hard time handling the ~550awhp at my lowered ride height. For the sake of reliability and simplicity a RWD conversion seemed like a smart move. I loved the grip and poor weather capability of the AWD system but it was a ticking time bomb and I got tired of driving gingerly as to not hard the drivetrain.
The process started with pulling the front driveshaft, axles, disconnecting the TC actuator, and some coding. It was as step in the right direction but not a real solution. A manual swap was always on the radar so I went ahead and collected a RWD manual trans, all the necessary components for the retrofit, and upgraded the drivetrain to M5 everything with an MFactory SMFW, Spec Stage 3 clutch, upgraded trans and diff mounts. This setup necessitated a custom M5 dirveshaft and custom trans support. I also relocated the DSC pump and swapped the module to a unit from a 528i since they were compatible with 535is.
I never found success integrating the DSC pump into the car, there were some issues with the VIN and region since there were never RWD wagons in the US, or so we thought. The wagon was operational but DSC/ABS was in a default and non-functioning state since communication was broken between the systems.
My front subframe was the steel AWD unit and I hacked up my old axles, removed the outer CV cup with the splines, and used it with the 36mm axle nut to hold my spindles together. Not ideal but it worked.
The xi steering rack was a bit slow and I found myself annoyed when I would have to regrip the wheel during fairly standard 90 degree corners, it was obvious the steering wasn't up to par with the rest of the wagon.
Enter the M5 steering rack retrofit. Of course the xi subframe has a completely different architecture to accommodate the axles so to swap the AWD steering rack to an M5 unit required swapping the subframe and nearly all components which was everything minus the passenger side engine mount. lol
Here is a list of components I collected for the subframe swap
- Aluminum RWD Subframe
- M5 Steering Rack
- M6 Convertible Sway bar (thicker than M5 and M6 Coupe)
- KW V1 (RWD E61 Fitment, special order from Germany)
- 535i Power Steering Lines
- Engine Supports R/L
- Driverside Engine Mount
- RWD Spindles
- RWD Hubs
- M5 Control Arms
- End Links and brackets
- RWD steering shaft and firewall grommet
...that's it!
The main benefit of this conversion is the M5 steering rack but a nice bonus is the increased amount of room the RWD subframe offers, if you wrench a lot like I do that it's a significant improvement. For those of you who have never worked on AWD N54 cars consider yourself lucky, they are a pain.
The other bonus is the weight savings. Comparing the assembled AWD subframe to the aluminum RWD subframe, ~55lbs is saved.
AWD Subframe = 43 lbs
RWD Subframe = 20 lbs
AWD Spindles = 38 lbs
RWD Spindles = 12 lbs
-26 lbs of unsprung weight is a nice!
Adding this weight savings to what I have already saved with the AT-MT swap and deleting the other front drivetrain means the wagon has shaved 200+ lbs with the conversions although was added back with the beefier M5 components.
On to the photos, the first few are a recap of other RWD related parts which were installed.
M5 drivetrain
RWD manual trans vs AWD auto trans
Stock xi open diff vs M5 diff, M5 heatsink needed to be modded to fit wagon.
AWD oil pan up top vs RWD oil pan bottom
RWD configured motor going in
Motor in
