While some of you avid GM...
While some of you avid GM High-Tech readers may have remembered, we took this lonely, barely broken in, little ol' 2008 G8 and started tearing into her like a red-headed stepchild!
Beyond nothing but a little dyno tuning, with absolutely no swapping of any parts, car owner Mike Ficacci, who also happens to be the Technical Editor of sister mag Super Chevy, laid the smack down on an '08 Mustang GT, also containing a tune. Now I don't know about you, but a two-door sports car getting a beat down from a four-door sedan really gets my blood flowing.
Next on the list for the G8 was to install a P-1SC-1 Intercooled HO ProCharger kit (featured in the March `09 issue of GMHTP). Beyond the installation of the kit, which includes a tune via ProCharger upon purchase, the G8 went from 303 rear wheel horsepower to 422 (via Cartek's Dynojet Chassis Dyno) for a killer advance in the power department. Not bad for a day's worth of bolt-ons, on what still appears to be a stock G8--minus the slight whistle from under the hood. Or is that a vacuum leak? Well, I guess that depends on who's asking.
What to do next? As you will come to find, the exhaust configuration is much less than desirable and being that we have yet to pop the seal on the L76 6.0-liter powerplant under the hood, we can't leave it virgin for too long. Why would we want to play with all those hours that the GM engineers have put into this monster? Because that is our job! To mess up a perfectly good running car in an effort to make it accelerate faster, sound meaner, and of course-anger the Dealership Service Manager next time we pull in for any sort of warranty claim. Guess we'll have to take the good with the bad.
As we're sure that you've all heard this analogy before, let's reiterate anyway. The engine is similar to that of an air pump, the faster you can consume the air, process it through the necessary avenues, and then expel it--the more efficient and powerful that pump can be. The same holds true with the gasoline-fed combustion engine. While the ProCharger forces air into the engine via pressure and volume, hence some serious power gains, we're looking for a less docile way of adding some ponies to this grocery-getter from hell. During this installment we'll add a set of SLP shaft rockers along with American Racing Headers' new G8 exhaust system. Why? By adding a little more lift it will allow for more volume to enter and be expelled from the combustion chamber, as well as freeing up the super-restrictive stock G8 exhaust system. Now let's head over to see Matt Hauffe and the gang at Tune Time Performance in Toms River, New Jersey, and get to work.
*Note -- The captions are being written in order to better understand the installations at hand; however, we installed the SLP rocker arms and valvesprings and then proceeded to dyno test the G8 for power and torque gains. Beyond that the G8 developed a slight tapping noise, which was attributed to the stock DOD (Displacement On Demand) lifter setup. At that time the engine was torn down to install a set of stock LS7 lifters, which alleviated our current and/or any future problems with the DOD system. Finally, the ARH exhaust system was installed and tested.
 Our first order of business...  Our first order of business was to remove the negative battery cable (for safety reasons) and the recently installed ProCharger P-1SC-1 head unit... |  ...Beyond removal of the head...  ...Beyond removal of the head unit, the valve covers and throttle body were also removed from the vehicle. |  Next, the stock intake manifold...  Next, the stock intake manifold was removed along with... |
 ...the coil assemblies, valve...  ...the coil assemblies, valve covers, stock 1.7-ratio rocker arms, and the cylinder heads. |  Moving to the sedan's underbelly,...  Moving to the sedan's underbelly, George (aka "The Bandit") began removing all fasteners necessary in order to rid the G8 of its stock exhaust (minus the mufflers). Pictured here are the downpipes containing the catalytic converters... |  ...Not that we are rocket...  ...Not that we are rocket scientists here, but does that bend look a little restrictive? While we don't have any data to support our theory, I'd probably lay some money on it. |