Long-time BMW guy here. When it came time to put some engine in my S13, there was really only one engine I wanted under that hood. Took about a year of work to get to this point.
Build specs:
- Engine: BMW B58B30A
- ECU: ECU Master EMU Pro 8
- Transmission: ZF GS6-37BZ
- Intake: Custom 3D printed runners (carbon-filled)
- Front knuckles + steering rack: E46
- Front subframe: Fully custom (bolts to OEM S13 mounting points)
- Rear diff: R200, currently welded - upgrading to E39 188mm with Racing Diffs LSD soon
- Power: 420hp
Took a lot of work to get this thing in there - the custom subframe was a project on its own. The B58 oil pan has a hump at the back that interferes with where the stock S13 steering rack lives, so the rack had to move to the front of the subframe. That meant front-steer geometry, which meant the OEM S13 knuckles wouldn't work anymore - and the easiest path to proper front-steer geometry was using E46 knuckles + matching E46 rack. One engineering decision cascaded into the whole front end being BMW.
Fun detail: thanks to the E46 knuckles up front, this thing runs 5x120/5x114.3 front and 5x114.3 rear.
Car sees both street and drift use.
Happy to answer any questions about the swap, wiring, suspension geometry, or why I didn't just buy an M340i.