Superchargers & Gas Mileage

[57AGIN]

I've been thinking about putting one of the Shelby superchargers, either the Whipple or the centrifical type on my 351W. My 57 is not used on a regular basis at the drag strip. I'm just looking for a bit more punch, without hurting my already miserable gas mileage 5 ? 12 pmg (depending on my right foot).

I've heard that the centrifical type of supercharger is designed primarily for higher RPM applications and at lower RPM's they are probably a parasitic loss (additional drag on the engine without compensating boost pressures). I've also heard that the Whipple type is more responsive at lower RPM's and produces more low end torque.

My question is when one of these two types of superchargers is mounted on a street machine and the driver seldom puts the pedal to the metal, what are the differences in gas consumption? This wasn't a consideration when getting rid of my Windstar, and getting a Shelby GT for daily driving (averages in the 14-16 mpg range around town).  My 57 is already a gas hog, I don?t want to make it worse.

Does anybody out there know or have experience with this?

Bob
57AGIN

[shopratwoody]

Bob,
A Paxton type would probably suit your needs better. To run a Roots type Blower, a engine should be
built for that purpose ie forged crank, good rods and cammed for that purpose. A roots type builds
a lot of heat, but they do work good!. I'm sure there are kits you could buy with  inner coolers etc.
Also you need to richen the fuel supply because of the added air pushed through the engine. I
would think there's a Paxton or Shelby blow through set up you could use that's designed for
a Mustang (5.0 type) Lots of places build and install this type. Have Fun
Ron

[Ford Blue blood]

My Shelby GT-500 gives me right at 15 to and from work, 14 miles door step to door step, about half and half town and interstate.  I will be putting a Lightning in my Ranchero.  Built from the ground up for a blower from the factory, has the program in the computer to take care of the gas/timing thing.  Priced the engine/transmission combo out of a wreck, $3000 for one with 65K on it.

[57AGIN]

Ford Blue Blood:

That sounds about right for the blown 5.4.  My 4.6 gets between 15 and 17 around town, but on the freeway going to the drag strip about 60 miles away my onboard computer indicate I was getting 23.2 mpg.  Since I'm running carberation on my 57 I'll not see numbers like that.  I just don't want to radically affect my already miserable mpg on the 57.  Maybe I'm just ""

Bob
57AGIN