A P1SC ProCharger centrifugal supercharger and air-to-air intercoolerwill be used to provide a large boost in power for our '04 GTO.According to ATI, "The P1SC features a fully CNC-machinedbillet-aluminum transmission case, a CNC-machined billet impeller madeof 7075 T-6 aircraft aluminum, and a cast compressor housing poured from356 aluminum alloy and heat-treated to a T-6 hardness beforeCNC-machining."
Sometimes 350 hp just isn't enough, and with all the unnaturallyaspirated Cobras, Corvettes, and F-bodies prowling the streets, the3,700-plus-pound '04 GTO really needs an edge to stay competitive. Butwhy just settle for an edge when you could have a sledgehammer? Howabout more than 525 flywheel horsepower on tap at the push of the pedalwith no bottles to refill? If this sounds like your cup of tea,Accessible Technologies Inc. (ATI) has a GTO ProCharger kit with yourname on it.
ATI's ProCharger supercharger incorporates some uniquefeatures that separate it from other offerings in the GTO superchargermarket. For example, ProChargers incorporate a self-lubrication systemthat does not use engine oil but rather a specifically blended oil (thatshould be changed every 6,000 miles) and an internal oil pump to coatthe working components during startup. The pump then aerates the oilinto a fine mist for optimum protection under harsh operatingconditions. So, not only do you not have to punch a hole in the oil panfor an oil supply, but the use of the internal oiling system also allowsthe ProCharger to operate at a cooler temperature, since it's notcirculating hot engine oil through the aluminum housing. ProCharger alsoincorporates a stepped bearing design, meaning it uses two differentsize bearings on the impeller driveshaft to help equalize the thrustload, which adds to the longevity of the unit.
This cutaway model (of a D1SC for illustration purposes) gives a glimpseinto the otherwise invisible operations of a ProCharger supercharger.Note the aggressive step-up gearing that drives the impeller also allowsthe use of larger pullies to create the same amount of boost as asmaller pulley would in other systems, yet still provides for a generousamount of belt wrap to prevent slippage.
ProCharger's air-to-airintercooler is a maintenance-free unit utilizing a straight- forwardapproach to intercooling but with some unique engineering built in.Besides being efficient (70 percent plus), these intercoolers areactually designed with a bit of restriction built in to promote more airtime in the core for heat transfer. Even with these restrictionsengineered in, the entire system creates only a 2-psi pressure drop.This allows cooler, denser air to enter the cylinders, and when combinedwith more timing and extra fuel, it makes for one heck of a powerincrease.
Now that you have had a glimpse into what makes the ProChargertick, let's perform an install on an '04 GTO!
The GTO ProCharger kit comes with everything needed to install it excepttools. It even includes a handheld PCM programmer that doubles as a scantool and allows end users to tweak the calibration to their particularvehicle. | 
Begin the installation by disconnecting the negative battery cable usinga 10mm wrench and then removing the front fascia. This is accomplishedby unscrewing the three Phillips-head fasteners holding the fascia underthe hood, then disconnecting the parking light/foglight harness locatedat point number 1. Remove the two Phillips-head screws that attach thefascia to the fenderwell area (shown as numbers 3 and 4) and gently pullthe fascia away from the Pontiac until the first two horizontal clipsare free from the plastic retainer (shown as number 2). The next part istricky and not mentioned in the service manual. At point number 5 thereis a vertical clip right next to the horizontal clips that were justremoved. Push the fascia toward the back of the Pontiac and up at thesame time, and gently rock it until it unclips. If you simply decide topull it out, there is a good chance you will break the clip on thefascia and it won't fit correctly; resulting in a large panel gap. | 
Remove the entire stock induction system including the airbox, thethrottle body tube, and the MAF. The stock airbox simply rides on rubbergrommets and pulls right out with a little effort. Then remove the upperradiator cover, which is held down by five pushpins. |
Lift off the Powertrain Control Module (PCM) cover and disconnect bothof the wiring harness connectors using a 7mm driver (or ratchet). Withthe wiring harness unattached, lift the PCM and the plastic mountingbracket out of the Pontiac. | 
Per the ProCharger instructions, unscrew the stock PCM perimeter casebolts using a T25 Torx driver and install the relocation brackets asshown. | 
Liberate the stock PCM heat shield (located between the exhaustmanifolds and the original PCM location, it simply snaps in) and trimper the instructions. |
Drill two holes and attach the remaining section of heat shield to thePCM relocation brackets using the included hardware. (It may be helpfulto use a hacksaw to cut the heat shield as it's quite thick.) | 
Remove the upper and lower radiator hoses and coolant transfer tube (theone that runs from the driver-side radiator). Keep these tubes handy asthey will be trimmed and reused later in the installation. | 
Disconnect the factory cooling fan harnesses and remove the entire fanassembly (the shroud and fans are in one assembly). The fans simply slipinto four retaining brackets (two on each side) and are held in bygravity, so lift straight up to remove them. |