any one played with MR2 superchargers?

[Chris Conlon]

At 09:03 PM 2/3/99 -0500, Robert Scott Winnicki wrote:

>specifically, anyone ever taken one of these off the MR@ and used it
>somewhere else, like say a rotory.  From what I've read about them they

I had sent a note in private but was thinking along the lines of "I
got one cheap, what can I do with it?", not "What SC should I get?".

The MR2 supercharger has a (slightly) bigger brother. In the US it's
used on the Previa S/C, and maybe nowhere else. It's ~15% bigger
than the MR2 unit but. One person pointed out, quite rightfully,
that the MR2 SC would likely be too small for your engine at full
tilt. But, consider that you don't need the SC to provide full boost
at WOT/redline, you need it to provide decent, instant boost at low
RPM to help spin up the turbo. So even a smaller unit *might* be
enough. What Steve N. said about hassles with bypass valves, is all
too true though.

There are at least 2 places I've heard of that claim to port or
otherwise modify the SC to increase the efficiency. I dunno how true
these claims are, but a 10% gain might be had.

If you're looking for a SC to spin up an oversized turbo, it sounds
like you want a positive displacement unit. A centrifugal
supercharger would be more efficient, but won't give much boost until
higher RPMs. Not exactly what you need.

If you're already looking at a full custom setup, I would seriously
consider the Opcon Autorotor, sold in the US as the Whipplecharger:

Whipple Industries
3292 North Weber
Fresno CA 93722
209 442 1261
209 442 4153 fax

(Hopefully this info is current.)  This is a Lysholm screw type unit,
which is positive displacement, but a lot more efficient than the
Toyota Roots units, or the Eaton modified Roots units. This means
less crank HP consumed, less heat and more boost. MacInnes mentions
this type of SC but says that it's too expensive for common use,
or at least it was at the time. Whipple sells bolt-on kits for a
bunch of vehicles, but don't really seem to be aiming at the hi-po
market, more like towing and hauling uses. And IIRC they have the
exclusive license to sell these units in the US, which, if they're
half as good as they sound, is a big loss for Opcon.

I plan to find out eventually. I'm oh so slowly building up a new
motor for my SC MR2, and one of the key changes is to lose the
stock SC and use a Lysholm unit instead.

If anyone here has actually *used* one of these units... I'd love
to hear more and maybe ask you a few questions about them.

   Hope this helps,
   Chris C.