With the rotor package removed...
With the rotor package removed from the GT500's Eaton blower, PHP's Karl Roekle smoothes and subtly reshapes the inlet area. This is one of the more labor-intensive aspects of the $1,499 Paul's High Performance Stage 3 Shelby upgrade package.
Horse Sense: The Stage 3 name suggests there might be other stages as well. Stage 1 ($775) consists of the PHP tune on the SCT flash tool, along with the cold-air kit. PHP's Stage 2 kit ($975) adds a 2.6-inch blower pulley (and compensating idler) and a 160-degree thermostat to the Stage 1's inclusions.
Few would argue that the Shelby GT500 is a performance animal right off the showroom floor, as you might well expect from the most powerful-and most expensive-Mustang ever factory assembled. But as we've seen time and time again, the S197 Snake's factory-rated 500 flywheel horsepower is really just the starting point of this thing's venomous potential. Highly effective (but not inexpensive) mods include swapping on a larger, more efficient blower from Ford Racing, Kenne Bell, or Whipple, but not everyone may be inclined to toss out their perfectly good OEM, hybrid-Roots Eaton supercharger just yet. If you find yourself in this latter group, we suggest the Stage 3 performance upgrade package from Paul's High Performance.
Mightily effective, as our dyno results show, the Stage 3 upgrade starts with some careful hand-grinding on the air-inlet side. You can either ship your Shelby's throttle body, blower inlet elbow, and the supercharger itself to PHP to have them internally reshaped, smoothed, and returned to you, or simply swap those components on an exchange basis for ones that have already received the porting treatment.
But the Stage 3 kit doesn't stop there. It also includes a smaller blower pulley installation for increased boost, along with a revised idler pulley so the factory serpentine belt can be retained. A 160-degree thermostat, PHP cold-air kit, and razor-sharp PHP custom tune loaded on an SCT X3 PowerFlash handheld programming tool round out the package.
 Our guinea pig for this installation...  Our guinea pig for this installation is Jeff Schmell's new '08 Vapor Shelby. At the time, it was totally stock except for a 3-inch off-road exhaust plumbed up behind the factory manifolds. (See our sidebar for a brief discussion of the pros and cons of 3-inch pipes.) |  Naturally, you can take your...  Naturally, you can take your GT500 to PHP in Michigan for the Stage 3 upgrade, but if you prefer to do the wrenching yourself, the task starts with removing the strut tower brace. |  Next, the factory airbox and...  Next, the factory airbox and inlet tube come out, a task preceded by some harness and vacuum/vent line disconnection. These will be reconnected to the PHP cold-air setup. |
 A clamp on the throttle body...  A clamp on the throttle body and a bolt on the airbox are about all there is to physically removing the factory air-inlet system. Note that the mass air sensor will have to be removed from the inlet tube and transferred to the cold-air inlet. |  Getting the throttle body...  Getting the throttle body off is no more complicated than popping off a harness connection on either end and wrenching out four bolts. And, yes, the throttle body must come off separately from the inlet elbow in order to provide access to some of the elbow bolts. |  Likewise, removing the elbow...  Likewise, removing the elbow is straightforward, and it has to come off to gain access to some of the blower fasteners. A couple vacuum lines and four bolts are all that's involved. |