What is a Rotrex supercharger?
A supercharger uses an engine-driven belt to turn an impeller that compresses air going into the engine. Turbochargers use a similar concept but use exhaust gases to turn the impeller. Because the engine drives the supercharger boost, it is directly proportional to rpms, producing instant response. The key technology in the Rotrex supercharger is a planetary traction drive system that provides a drive ratio of 12.5:1, allowing the Rotrex impeller to spin much faster than conventional centrifugal superchargers and at speeds even slightly faster than a turbocharger. Faster impeller speeds allow the Rotrex to use a more compact impeller wheel and housing, but even more importantly, an increased efficiency. Since there are no hot exhaust gases running through an exhaust housing like in a turbocharger, the Rotrex runs cooler and produces efficiency numbers unrivaled in aftermarket kits. The cool running temperatures, compact size and instant boost make the Rotrex supercharger an excellent choice for snowmobiles.
The MPI kit is very impressive. All the components have been carefully machined to work around the stock machine and the fit and finish of the kit is on par with how the stock machine is built. Abe and Mac reassembled the machine and it was ready to go. The whole installation took roughly six hours and although many of the steps can be done by anyone with basic mechanical knowledge, a few steps do require patience and mechanical finesse. Anyone installing a kit must always keep in mind that one small error during installation could compound and turn into a much greater problem once the machine is on the snow. (And repairing machines in waist deep powder is definitely not ideal. It is much easier to take it slowly and do it right the first time in a nice, warm shop.) MPI has several experienced technicians available by phone from 9 a.m. to 5 p.m. every weekday to assist customers with installation and tuning issues, should you decide to tackle it on your own.