1st Gen S Most liked posts in thread: Old supercharger for an old car

I'm making another MINI M62 kit. The word is finally getting out that it is a good low cost alternative to a TVS900 or even a rebuilt M45. Just about instantaneous 38% more air pressure. I sent one to a guy in Greece and he told me it cost him a little over 900 euros in his build, 1/3rd the cost of a TVS900. The guy in Pittsburgh that specializes in Cobalt parts has sent a bunch over the pond and also has sold five to guys in the States.

I changed my procedure a little using a 3mm plate to adapt the discharge horn to the deck and also shaped some aluminum bar stock so that it can be attached to the case to add more sealing surface area. I had no sealing issues with my first kit but the larger area lets me go with a different charge duct connection for easier removal.

 

I think the Lotus used the Magnuson MP62. Same displacement but older version needle bearings and port technology than the Cobalt/Saturn M62. DDM used the MP62 in their 2007 attempt to produce a kit for the R53 back in 07 but the costs that were projected at that time for $4000 was too much for the market to bear.

If you do the work yourself the cost to install a M62 is much much less.

 

A turbo provides basically free horsepower where the supercharger is parasitic. Then superchargers vary in their power consumption as well. Harrop's TVS900 is the most modern R53 substitute and it has very good volumetric and adiabatic efficiency values but it also appears it consumes more power to spin than either a twin screw or the older M series Eaton. I made this chart up to show some approximate values between the M45 and the M62. The overall pressure increase cannot be denied and as long as IATs are mitigated with a different type of intercooler, or, a water/meth injection system power gains are readily available with proper tuning.

From my own experience running M62s for more than 2 years and thousands of miles, I think with BVH and a JCW sized pulley the M62 is capable of surpassing the OEM ECU max boost point.

this boost is able to provide some good power gains without timing retard.

 

This is a MP62 kit I made for friend a couple of weeks ago It does have shorter rotor tips and hence shorter needle bearings so the spin rating is less. The second picture below are the MP62 rotors where the last picture is the M62 rotors. You can see from the socket I used for comparison the M62's are about 1/4" longer. The M62s use the same needle bearing as the TVS.

 

With some paper mache, fibers and JB Weld I enlarged an OEM charge tube for the 2nd M62 kit I am working on. Its 3/4" shorter than the M45 tube but has 25% more volume. I will enlarge the throttle body side to accept a 760i throttle body that has a 64 mm butterfly vs the oem 58. I just did some skimming and will do a final sand tomorrow. In the second picture I have the piece I cut out next to what I infilled so you can see how much wider this modified one is. From past experience there is not any issues with this hitting the radiator.

The supercharger end is the same size as the M62 intake and the vacuum ports for the MAP and Brake lines are still in place. The 760i throttle body has the same bolt spacing as the oem so it bolts right up.

 

After a final sand and some paint I boxed it up and sent it to the UK. A shop over there has 6 Cobalt SS M62 kits that they will be selling. This larger tube will be 3d scanned and joins an earlier adapter that allows the oem m45 charge tube to be cut and joined. The larger charge tube and the adapter both have a final shape very similar to the size of the M62 intake.