I have been in contact with a VERY knowledgable installer about the
Kenne Bell vs Allen supercharger question. I decided I would rather
have the Allen supercharger. Below is his reply to me for those who are
interested. - John
Kenne Bell vs Allen Supercharger (6 psi systems)
I would not expect much more hp (from the Kenne Bell). Yes, it is more
efficient (75% versus 60% adiabatic) and yes, it will have slightly
lower discharge temps. However, that is not lower than the Allen with
an intercooler. I suspect the power output is somewhat similar but the
Allen still has a much better intake design and the intercooler. The
temperature entering the cylinders will still be lower with the Allen.
KB uses the Autorotor compressor which is a good unit but it does not
even compare to the Eaton for quality and reliability. I had to replace
one for noise and I had a second that was even noisier. I have never
seen the Eaton fail in any way and they come factory on many cars from
companies like Mercedes, Jaguar, Aston Martin, Ford, GM, and the list
goes on. I am not away of a single major auto manufacturer using the
Autorotor. Also, the screw builds pressure internally at all times
which drives more parasitic loads at cruising speeds, wasting more gas.
The Roots draws less that 1/3hp at cruise so you retain your fuel
economy. The bypass valve also helps with the parasitic losses and
keeps the unit cool when not in boost.
On a scale on 1-10, 1 being paxton (piss poor),
Allen scores a 9.5 for product support. Kenne Bell scores about a 7.
Reliability: Allen 9.5, Kenne Bell 7
Driveability: Allen 9.5, Kenne Bell 8
Kenne Bell is a good product and a decent company to work with. Allen
is just much better. Both are far better than any centrifugal.