2008 Pontiac G8 GT Procharger HO Intercooled Supercharger System Install - Four Doors Of Fury

The piece of wiring harness leading to the MAF needs to be extended, since it's now located on the opposite side of the engine bay. ProCharger is hoping to have a simple plug-and-play extension harness available for production kits, but for this early kit, the wires are cut and extended. This should not diminish the functionality or reliability of this wiring, but just adds a few more minutes of labor to the job.

The power steering and washer fluid reservoirs are filled at this time. Waste of a photo, right? Wrong- I'm reminding you that even the little things matter in a relatively complex install such as this. Forget to fill your power steering fluid, and the whine you hear won't be the blower; it means you'll be buying a new power steering pump. Got the picture?

ProCharger's ProFlow bypass valve gets partially preassembled with the appropriate hoses on either side before going on the car. This valve, good to about 700 HP, comes preadjusted for use with the G8 kit.

The ProFlow bypass valve sits just beneath the head unit, as seen here through the driver side headlight hole. It will get a vacuum source on its gold fitting via a special "vacuum manifold" ProCharger supplies (it taps into the brake booster line).

The black supercharger intake "hat" is next. It needs to have one of the hoses leading from the bypass valve attached onto the bottom of it before it is pushed into place on the compressor inlet. We've disconnected the fuel line from the fuel rails in preparation for swapping injectors, and are letting the extra fuel drip onto a white rag.

A new PCV hose connects to the factory fitting on the front of the passenger side valve cover. This is the "fresh air" hose for the PCV system. Its other end attaches to the supercharger intake hat.

The fuel rails come off. All of the fuel rail bolts must come out to accomplish this, as well as the second to rearmost intake manifold bolt on each side. The rearmost manifold bolt on each side must also be loosened, though not taken out completely. This allows the "stop" brackets at the rear of either rail to yield enough clearance to get the fuel rails out.

Here's one of the new fuel injectors. "My heavens, they look just like the stock ones!" you exclaim. The similarities in appearance can be traced to the fact that they once were stock injectors, but have gone under the knife, so to speak, for some invisible improvements. They've been modified by FAST for additional flow (50 lb/hr vs. the 42 lb/hr stock rating). Don't mix them up!

The aforementioned vacuum manifold is spliced into the brake booster line at the driver side rear of the engine. A #6 hose clamp goes on each end, but the small forward-facing barbs do without clamps. One of these barbs is for use with a boost gauge, be it an in-car unit or just one for the dyno; it will be capped off when not in use. A bit below the vacuum manifold one can just barely see a new white check valve that has been inserted inline with the hard plastic emissions line (look just aft of the rearmost ignition coil plug). Also visible at bottom right is the conical cotton/gauze air filter that has been clamped onto the intake hat.

With the system installation pretty much wrapped up, the G8 is reassembled. The plastic radiator "scoop" is not reused (it likely can be trimmed to fit if desired, but remember, ProCharger wants to keep the installation totally reversible, so the boys opt to leave it out here). The large plastic front underguard, on the other hand, is reused; it is secured with two bolts and a dizzying array of plastic pop rivets. Check out the visibility of the intercooler- can you say "intimidation?" (Try again, you pronounced it wrong.)

The completed installation is mighty fine lookin', don't ya think? All that black and shiny metal... and what's that, a purple air filter smack dab in the middle of things in the engine bay? ProCharger says that even though it's located in the engine compartment, underhood temps are kept in check whenever the car is moving thanks to the flow of oncoming air. Also, though not present here, the factory engine cover is said to act as a heat shield; it fits with some trimming to the front driver side. Check out ProCharger's website for a photo of a supercharged G8 with the engine cover in place.

ProCharger provides a "tuning certificate" to purchasers of the HO Intercooled Supercharger System, allowing owners to mail their PCMs out for installation of the ProCharger-specific tune that is included as part of the purchase price of the system. However, due to the time constraints and early production nature of this installation, Cartek installed a custom tune in our test vehicle. The dyno results: 422.8 HP and 396.1 lb-ft. That's SAE-corrected increases of nearly 120 horsepower and 65 pounds of twist, which by our estimation comes to within a dozen ponies of ProCharger's 540-crank hp prediction (you can probably chock the difference up to the aforementioned gear ratio discrepancy from that which we're used to). Let's hear it for high-powered 4-door GMs!