I've been thinking about putting one of the Shelby superchargers, either the Whipple or the centrifical type. My Shelby GT will not be used on a regular basis at the drag strip. I'm just looking for a bit more punch. 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, which averages in the 14-16 mpg range around town. My Shelby does considerably better than that, again provided I keep my foot out of it. But, since the car is my daily driver and I put about 10,000 miles a year on my car gas usage is a consideration given todays prices and what the future may bring. Does anybody out there know or have experience with this? Bob
A friend of mine just installed a Kenne Bell on his 07 SGT and got 26 mpg average all the way to long beach from las vegas. Best, Vern
This past year I modified a Ford FE with the addition of vintage Paxtons. Even with the superchargers I dialed down the primary jets to run a bit leaner & meaner. To compensate for demand conditions I drilled the Power Valve Restriction Channels in .003" increments until I had sufficient enrichment. The engine is flexible enough to allow lugging it down to 25 MPH cruising around the local shopping mall in 4th gear on a hot Summers day. On the other side of the coin you can witness your future rushing toward you at a mind-bending pace at 1/3 throttle. Results: 42.3 mile test loop on two gallons of fuel = 21.15 MPG The test loop was 1/2 interstates and 1/2 rural driving. Dual Holley 600 Double Pumpers; 66 Primaries; 76 Secondaries; 6.5" Power Valve Timing 12 degrees initial; 20 degrees mechanical; 7 degrees vacuum advance. My understanding of gas pressure is that if you double engine speed your pressure is 4 times (Squared) If you back engineer the figures: The paxtons are full in at 6000 RPM Producing 6 Lbs. of boost each. At 3000 RPM they should produce 1/4 or about 1.5 lbs each. At 1500 they should produce .375 lbs. each and idle at 950 would be a bit over .1 lbs each. It doesn't sound like much but if you figure 230 HP gain at 6000 RPM it would yield 4-5 HP at idle to offset parasitic loss. The Paxtons spin 4.41 times crank speed so they turn 4190 RPM producing a large volume of air at idle. - Geary
Thanks for the quick and informative replys. It looks like I could go either with either of the superchargers and not blow the mileage. In looking at the available options is there anyone out there having experience with both types of superchargers on a 4.6? Reliability, longevity, general responsiveness, etc.? Bob
After running the Paxton supercharger off and on with my carb injected '66 GT350, I noticed about 14 mpg with vs 12 mpg without. Got up to drive speed faster (on on ramps or passing), so I was able to get to higher gear and off the accelerator sooner. The engine ran better and never got vapor lock. How some of the 5.0 and 4.6 run I guess is a mater of how you drive with the extra power. I would be interested to know the mpg difference as well. Also, has anyone noticed any premature wear on the engine or drive train in general from long term use (after maybe 50,000 miles) of a hairdryer add on.
I have a KB stage 2 in my SGT and I average about 23mpg almost every where I go, I also have an automatic and it is a blast to drive, Rick
Potty: Thanks for the input re your Kenne Bell installation. I will probably go with the Whipple system Shelby installs in in his Las Vegas shop sometime after the First of the New Year. Did your installation affect your warrantee? I believe that the Shelby installation isn't supposed to adversly affect the SGT warrantee. Bob
No warranty with the KB, I just liked the look of the KB and I would not change a thing I have done, They also install the KB in Vegas, you cant go wrong with any s/c, good luck, Rick
Vern, This one does not have a CSX pedigree. She is known as Aggressor. The car is based on a Unique Motorcars replica. In Spring and Fall 2000 my wife and I had two private showings of CSX3015 while it was owned by David Scaife in Pittsburgh, PA. We built our replica in 2001 to be fairly true to the original. We added the superchargers to complete the car last winter. The addition of the superchargers should place the horsepower in the mid 700's range.The superchargers, bracketry, and mounts are as original and much has been replicated. We have taken a few creative clearances such as installing a toploader and bumper package. Two double pumpers also take the place of the original vacuum operated Holleys. Eleven Stewart Warner Deluxe Gauges support the cars functions including a custom made 240 MPH speedometer. A few images are provided below for your review. The massive hood scoop had to be reshaped with the addition of the blowers. We shaped the hoodscoop working from photographs of the original in 2001. We failed to leave enough clearance for the blowers so it was just reshaped and is still in blue primer. To date she has been shown extrensively and has been a featured vehicle in two Motortrend Productions auto shows. She carries 53 competition show trophies has been raced . (Yeah I'm a bit proud of her) -Geary
Hey Potty, I also have an automatic white 2007 SGT that I would like to supercharge. A few questions if you don't mind: 1) Do you worry about the boost and melting your engine? 2) What did you set the boost to? 3) How much of a difference in acceleration do you feel? 4) Does the tranny work ok with the increase in torque? 5) Did you get your car dyno'ed afterwards or did you just go with the kit installation guidelines for re-chipping the fuel card? I live in SoCal so am somewhat interested in Shelby doing it in Las Vegas. But I think they are 10k. The Ford dealership here locally will do it for 7.5k. And I have a speed shop giving me a price now. I've always been a little concerned about the supercharger putting to much strain on the engine and the transmission. Thanks!
#1 No #2 10lbs #3 It will get your attenion quick #4 TCI upgrade kit- all is good so far #5 I have had it dyno'ed without the stage2 and was 465rwhp stage 2 it pulls much harder w/ 1500cfm throttle body I had another shop install the s/c and they also dyno'ed it, but I do not want to know with the stage 2, It is scary fast, Kenne Bell installed 3 differnt tunes on the SCT3 and I can drive it with ease on the streets, we will be in LA tomorrow for the shelby b-day bash and then off to vegas, Rick
