Subject: [Fwd: 06 Mustang kit being discussed on internet...]

My response is that someone is trying to sell KennBell kits on the internet.
We hear this comparison all of the time. The only time that a screw has an
advantage over the Eaton/Roots style of supercharger is over 10 lbs of
boost. We have maps and all of the technical data that Eaton has evaluated
over the years.

The statement that the screw is better than the Eaton is confusing because
we remove many of the compromises from the supercharger unit that Eaton
designs into the supercharger as dictated by the vehicle manufacturers. We
change the housing, the air intake track, discharge ducting and the rotor to
housing sealing and clearances. Our supercharger (Magnuson) when compared to
the Eaton piece is a much improved unit and it is not out of the ordinary to
see a 30-40 HP increase just by changing the supercharger.

Another common statement is that the screw is so much better than the Eaton
and that is why the are used on the Cobras etc. What everyone seems to fail
to mention is that on the Cobras and the Lightning etc. is the forged
components in the engines. Bolt on a screw and make 12-15 lbs on a stock
Mustang motor and you will be blowing the rings out the tail pipe just
before you run over the crankshaft. The accepted maximum horsepower output
of the 3V motors is about 425, after that you are asking for component
failures. Ford asked Eaton to design a supercharger to accomplish a specific
torque and horsepower rating, be quiet, last for 100,000 miles, pass all of
the stringent durability and validation processes, be inexpensive and that
is what they did.

The Eaton supercharger is a superior unit for street operations; the screw
is not more efficient on the street. The horsepower required to turn the
unit is not less at 10 lbs of boost, the discharge temperature is not less.
The fact that the MP or Eaton units have the bypass valve makes it a
superior piece for street applications. How many OE vehicles to you see that
have a screw on them?

Let me know if there are any specifics that I can help you with. Ask the
persons making all of the claims about the superiority of the screw to
supply any technical data, I haven't seen it and I been doing this for
years.

As far as the centrifugals are concerned, they require impeller tip speed to
make boost. The lag is inherent to the fact that they convert speed energy
into pressure. They work great when run at a steady speed; the roots type
has the ability to make boost right off of idle which increases the fun
factor greatly on the street.


Bob Roese
Magnuson Products