An important element of the supercharger conversion is the induction system to ensure cool, clean air is supplied to the supercharger and subsequently to the engine intake. To the best of my knowledge I am developing one of, if not the first supercharger conversions for an R1 powered mini. It's therefore not possible to buy a ready made induction kit off the shelf.
I have been gathering parts over the last couple of months to enable a system to be fabricated. I have also designed my own parts and started having them made or I am making them myself.
A supercharger will be trying to force air into the engine intakes even at low RPM. The engine can't always handle the extra air and pressure depending on where it is during the intake cycle so it's important to be able to bypass and recirculate the extra air.
A blow-off valve could be used which vents the unwanted air back to atmosphere. However, these can be very noisy and its a waste. A bypass valve will recirculate the air back into the inlet side of the supercharger.
I decided to buy a bypass valve intended for an R52/53 BMW Mini. They are cheap and easy to source from eBay.
Here we have a picture of two 6mm laser cut aluminum flanges I designed. The one on the left is for the bypass valve and will eventually welded to an aluminum pipe that links to the SC inlet. The one on the right is a MAP sensor boss that will be welded into the SC output pipe.
For the engine airbox/plenum I will be using a Pipercross 600 series airbox designed for 4 cylinder engines. It has a very low profile and should fit well in the space between the engine and mini bonnet.
I ordered a blank backplate so that I could cut the holes to suit the R1 intakes.
Here we have a picture of my R1 airbox prior to me removing the rubber trumpets and cutting out the intake temp sensor mount. I have made a template of the hole spacing and I plan to cut the Pipercross backplate with my plasma cutter.
The standard R1 airbox has a few connections that were easily identified by looking in the Haynes manual. I won't need to replicate any of the connections labelled A, B & C below but I will need the boss for the air intake temp sensor (6.3 below).
Connection B is the crankcase breather. As I am supercharging the engine via the airbox I don't think it will be a good idea to connect the crankcase to a pressured plenum so best to just add a breather filter directly to the crankcase outlet.
I purchased a kit of aluminum pipes from eBay to form most of the pipes that will connect all the various components together. Once I have all the major items mounted I will be able to work out the pipe routes and cuts required.
I've chosen 63mm (2.5") pipes which seemed like a common size in use. It's certainly a larger diameter than the standard AMR 500 ~ 34mm.
Still to purchase is a charge cooler and an enclosed air filter. I am considering a Ramair item.