Originally Posted by Gearbanger 101

There is indeed. Although only made popular recently, the inverted blower design has been around since the late-90's.

The theory behind it is that not only does it allow for the use of longer runners (which we know promotes better low end torque), but the incoming airflow only has to make 1 180* turn upon exiting the discharge port of the blower before entering the cylinder heads, limiting distortion and turbulance. Where with your standard top mount blower system, the air has to make 2 180* turns which adds to the restriction and ultimatley slows velocity to a some degree.

Case in point....here are a couple of photo's of the ALLEN set up (the same one I've got on my 2V '96 Cougar XR7). The originators of the inverse blower design.

The original REV I kit





Underside shot of their later REV II design



Their old 2V F150 kit



Although because of their use of a smaller Eaton M90S blower, the ALLEN kits were never huge horsepower makers, they did however put out plenty of torque and at very low RPM. My little 4.6L PI engine puts out 430lb ft of flywheel torque as low as 2,200RPM. That's about 220lbs ft of torque more than it was putting out in stock trim at that same RPM.

Originally Posted by stanger_missle

Hey, an Allen supercharger! I thought nobody has ever seen these. My only experience is from my old Mustang club. The chapter president had a 1996 GT with an Allen supercharger. Interesting design. Sorry, I got off topic LOL...