ASC Fabrics

I've always loved doing engine swaps, having finished a few smaller scale ones over the years, but what I've always wanted was something a little crazier. I first got into BMW's by owning an E36 M3 convertible and didn't stray too far when I got into Z3's, which I have owned continuously in various types for over a decade now. They are as good to look at as they are to drive. After I finished my last engine swap for a customer I decided my next swap was going to be for me, so I could do it exactly how I envisioned it. When I started to think about what engine swap I'd want to do for myself, I had two big sources of inspiration - I always loved the Shelby Cobra and have always been fascinated by the BMW Z3 V12 that was built internally by BMW themselves in the late '90s. The idea of building a "German Cobra" with a big BMW V8 in the small Z3 roadster chassis was born.

 

I chose the N62 engine because it has some really fascinating technology, including a continuously variable length intake manifold that boosts torque across the entire RPM range and Valvetronic that helps increase throttle response and increases efficiency by varying valve lift instead of using a traditional throttle body. It also offers around 370hp and over 500N-m in the right 4.8L configuration. It also offered some advantages for the swap - being a rear sump design meant the oil pan didn't require modification, the engine computer used the same canbus protocol as the donor chassis and it was a much better value proposition, being a small fraction of the cost of an S62 engine while offering just about 30 hp less but with more torque and a broader torque curve.

 

A major goal of the swap was to build it "as if BMW had built it" and this ethos will feature prominently in many of the decisions made. On that note, a lot of consideration was also given to serviceability, it was absolutely critical that basic maintenance tasks could be performed with the engine installed. I did not want spark plugs to be an engine-out job. Once it was installed the engine is actually easier to service than many of the cars it came in - the Z3 engine bay has a lot of room and I've even done valve stem seals with the engine in place, spark plugs are a 5 minute job and basically everything can be done with it installed. I have yet to pull the transmission with it installed though. Anyways, onto the swap!