Hi all, I recently sold my E92 for something more practical, and ended up purchasing a 2008 BMW 535XI wagon. I love the drivability of these cars, and with the “tuneability" and surplus of aftermarket parts available for the N54, and so the 535 wagon seemed like an excellent choice.

My plan is to build a 400-500hp daily driver, retaining as much practicality as possible, while still building a performance-oriented car. I initially was considering a unique single turbo solution, but after investigating this route, the headache seemed like a larger expense than just going with twins, and all of the bolt on plumbing that goes along with hybrids.

My plan is to run a larger frame turbo, either a Pure Stage 2 kit or a similar specced kit from RB, and tune the car to behave like a single (ie LOW boost early on; the goal here is to keep the transmission as long as possible).

I will most likely be purchasing new parts, however if you are selling any of the following, I’d be happy to take old parts off your hands:

Inlets (relocated/not relocated doesn’t matter
Outlets
7"+ Intercooler (brand does not matter)
LPFP Stage 2
PI or Prometh Kit
N20 Sensor/harness
KW V3 E61 AWD Coilovers
XI Downpipes

Once the turbos are cut and shipped, I will begin planning the install. Most likely at the some point in May. I’m very excited to embark on this process and overcome some challenges along the way.

In addition to the bolt ons, the car will have a custom oil cooler that I’m working on, and a custom transmission cooler system to keep the temperatures low. Reliability is the number one goal of this build, and while nothing will be as reliable as stock, spending the money now and installing the necessary parts will be cheaper than fixing a catastrophic failure down the line.

Eventually I’ll convert the body panels and fenders to the M5 style, and wrap the car, but for now I would like to ensure the car is mechanically sound, and then the aesthetics will come.

Thanks!

 

Welcome and congrats on a good looking car!

I like the list of mods, I have been much more conservative but I am really happy with the little I've done...in my case I care about long trip efficiency, I have it tuned to about 360 HP and I am getting 26 MPG at a conservative 70 mph average (I can actually make it give me 29 MPG at a lower speed but it is just too boring). I just completed a 600 mile drive, car full of people, dog and luggage, average speed ~80 MPH and averaged about 23 MPG...so I can't complain. If I didn't care about that I would've already done just about the amount of mods you will. I am sure you will have fun doing them and will really enjoy the new beast!

 

hi 2

 

Car looks great! What downpipes are you going for? I'd like to swap my DPs but fitment is a concern.

 

Thank you guys for the warm welcome. I initially had a plan to source the turbos from Frankenturbo, however upon further research, their products do not prove ready for production, and dealing with the headache of inevitable failures that occur in R&D is not something I want to do right now.

Most likely I will be sourcing the turbochargers from RB or Pure, both have been producing excellent products for years.

As for the DPs, I am using AR-Design High Flow Catted Downpipes for the E61/E60 xi/i. I believe VRSF has catless option as well, however that is not the route I chose to take.

The real limiting factor here is the front differential, which I am sure will break in a matter of time. After all the bolt ons are installed and the car is running well, the drivetrain will be the main challenge to tackle.

 

Well, if the plan is to stay AWD instead of converting to RWD AND you don't mind being a guinea pig...

The F90 M5 has AWD...

 

Not the worst idea, but also not the cheapest. To keep the car AWD a drivetrain swap is likely the cheapest solution, so I will be investigating this opportunity. Some of my friends are also a bunch of hardcore mechanical engineers with access to a variety of CNC facilities, so a custom front differential might be a route to take down the line. For now I have a bad oil leak that I'm 90% sure is a rear turbo seal. But we will see once the motor comes out.