RX 911: The Madness Behind This Classic Porsche's Rotary Engine Swap

A 911 With Rotary Power: Something doesn’t sound right

The cold start of the classic Porsche reveals a dirty secret – a 13B rotary engine from a 1996 Mazda RX-7 FD. Porsche purists would go mad, especially considering this 1966 Porsche 911 was the first 911 to get Porsche’s iconic Mezger engine. According to the owner, the engine is brand-new with everything being polished of chrome. It also features a single turbo that’s "big enough” and has been built to handle 480 horsepower on low boost.

Jeffrey says that the engine can be tuned for up to 690 horsepower but wants to keep things civil for the street. Power goes to the rear wheels through a built Porsche 915 transmission, which was introduced back in 1972 for the Porsche 911 Carrera 2.7 RS, and was produced until 1986. Jeffrey’s rotary 911 build also utilizes 930 Turbo axles. Apparently, all you need to mate the Porsche transmission to the rotary engine is an adapter plate, in this case, supplied by Kennedy. There is also a Stage 3 clutch.

An original Porsche 911 that borrows design cues from the 993 and 964

You can tell that up until the 996 generation, the Porsche 911 hasn’t changed much in terms of aesthetics. The car started as a 1966 Porsche 911, but Jeffrey decided to go with a 993 aesthetic for the most part. The end result is a car that can easily pass for a Porsche 964 Turbo because the 993 had more heavily sloped front wings. We don’t know what the car looked like before the transformation, but it may have been a shell, judging by the owner’s words. This would explain the controversial swap, given that Porsche boxer engines are an inherent 911 trait. Jeffrey made extensive use of 993 bits, including the door mirrors, door handles, and fixed rear windows instead of the original, pop-out ones.

The most obvious addition is the iconic Whale tail at the back, which came from a 993 GT2. The front bumper is also from a 993. There is another Mazda part on this Porsche – the sunroof, which comes from an RX-7. The owner of this car made sure that the glass sunroof could be quickly changed with a solid piece, which makes the Rotary 911 legal for track use. The flared fenders are fiberglass at the rear, and metal at the front, and the whole car is finished in Speed Yellow with a touch of green pearl. The only original body part is the front hood.

The interior is the most classic aspect of the build

The interior retains the classic layout but has adopted a motorsport twist, thanks to digital racing gauges, half-leather bucket seats, roll-cage, and Tanaka racing harnesses. There is also Alcantara on the dashboard as well as a modern twist on Porsche’s classic Tartan interior. The door cards are lightweight and now feature straps instead of door handles.

The owner doesn’t specify weight figures, but you can bet it will be much lighter than the current Porsche 911’s curb weight. The original 911 Carrera weighed 2,381 pounds, given all the work that has gone into this build, you can expect it to be lightweight, but with roughly four times the horsepower (on a conservative tune), resulting in a power-to-weight ratio of around 444 horsepower per ton. But by far the most unusual trait is the way this rotary-powered Mazda sounds. Take a listen to the car in the video below.