Transplanting a Yamaha R1 engine into a classic mini might be a little crazy but wouldn't a supercharged one be even better?!
Following a ride in my friends new Lotus Exige S I couldn't get the idea of having a supercharger out of my head. The noise and torque is so addictive. I started conducting a little research and couldn't find much for inspiration. A company called TTS Performance produce a supercharger kit for later R1's but sadly not for my 2003 5PW engine.
Not letting the lack of off-the-shelf kits get in my way I have set about creating my own! The main obstacle to overcome is finding a way to get drive from the engine to power the supercharger. Sadly the standard R1 engine does not have any external pulleys to use so I needed to come up with a solution.
Ideally you want to attach a pulley to the engine crank so that the supercharger spins up at the same rate of the engine RPM. There are two possible places to do this on the R1 engine from what I could find. The stator or the timing chain output. The stator will be obscured once the engine is installed in the car by the drive chain connecting the gearbox to the driveshafts so the timing chain side it is.
I have designed a custom timing chain cover that incorporates a housing for a bearing and oil seal that will hold a custom shaft connecting a pulley to the crank via something called a cush coupler. Cush couplers are used inside superchargers to transfer the nose cone pulley input to the internal rotors.
My design is based on the same principles of a supercharger using a cush coupler to connect a pulley to the crank. A belt will be attached to the new pulley running up the side of the engine to an Eaton M45 supercharger. The same supercharger used on the early BMW Mini's except mine is from a Mercedes as it does not have the water pump outlet that comes on the Mini version that would need blocking off.
Eaton M45 superchargers can be picked up on eBay between £100 - 150 at the time of writing. They are often listed using different reference numbers so here is a handy list.
More to follow in another update.