To some it's Deja vu; to others it was simply a matter of time before GM tried to market another Holden in the United States. This time, however, the offer seems to have something to please everyone-and plenty to scare its competitors. It will undoubtedly have the same exceptional Holden build-quality and materials we've come to know and love since the GTO hit the US. The G8 will be offered initially in two flavors: a "base" model, and the uplevel "GT" version. Building on the base model's already impressive list of features, the GT adds a sportier suspension, styling cues, and of course, the all important V-8.
The G8 GT, shown here at Holden's Headquarters in Australia, is a good indicator of what the actual production car will look like when it arrives in the US. Note the production size/style wheels and tires. The body lines are the same as the show car-a welcome change since GM has a history of teasing us with the styling on show vehicles and then radically altering them for production.
CHASSIS AND BRAKES
An independent suspension is standard on the base and GT models. Both sport a 114.8-inch wheelbase with 62.7-inch front and 63.3-inch rear tracks. The front suspension is a strut-type/multi-link-style design with a stabilizer bar, and camber, caster, and toe are fully adjustable and customizable. The rear suspension uses a four-link independent setup, with non-adjustable coilover shocks, as well as a stabilizer bar.
A hydraulic power steering rack is located ahead of the front axle centerline, which adds to the balance and responsiveness of the car, and the braking system is also quite remarkable on paper. Both brake systems use discs at each corner, sized relative to the trim level's performance. Naturally, the GT features a larger braking capacity of 12.64-inch front, 12.76-inch rear rotors, while both trim levels include twin-piston PBR calipers up front and single-piston PBR calipers out back (along with integrated traction control and ABS).
DRIVELINE
The G8 Base V-6 is coupled to a standard five-speed automatic. This powertrain team is best compared to the 3.6L Cadillac CTS, as they share the same engine and transmission; however, unlike the Caddy, there is no indication that the G8 base will be offered with a five-speed manual option. On the other hand, the G8 GT comes standard with a 6L80 six-speed automatic with a steep First Gear to get the 4,000-pound G8 out of the hole quickly. While the initial offering of the G8 GT will only offer the 6L80 transmission, gear rowers rejoice, as the venerable six-speed manual will join the fray soon after production begins. Regardless of your engine or transmission choice, all that power is channeled via a two-piece driveshaft to an independent rearend with a final drive ratio of 2.92:1 for the six-speed automatic. While this may seem meager, the 4.03 First Gear should make up for any second thoughts. The final drive for the upcoming six-speed manual is 3.27.
While the L76 destined for the G8 GT doesn't appear terribly different from its Gen IV counterparts, it does incorporate quite a few changes (including variable cam-phasing, to allow it to make 362 hp on regular fuel).
G8 BASE-LY7 3.6L "GLOBAL" V-6
This 3.6L screamer develops a healthy 261 hp at 6,300 rpm and 250 ft-lbs at a relatively low 3,200 rpm, and incorporates interesting upgrades over the original LYZ (like a variable intake system). Controlled by the ECM, the intake manifold houses a valve in its plenum area, which opens and closes according to engine speed and load. The valve begins to open just off idle and then closes higher in the rpm band, creating two inlet plenum ports for half of the cylinders. This system allows the LY7 to develop low-end torque much greater than that of a standard 3.6L engine, while still making a lot of top-end horsepower. It's amazing to think that to get close to these numbers before, we had to slap a 90ci supercharger onto a 3.8L. The LY7 also incorporates new Bosch dual spray injectors that have two individual nozzles for more complete combustion through increased atomization, and of course more horsepower, to boot.
The LY7's block and cylinder heads are sand cast from A319 aluminum. The block features six bolt mains and cast-in iron cylinder liners, housing forged aluminum slugs that are cooled via oil-squirters aimed at the underside of the piston.
The LY7 or global V-6 doesn't look like much, but it can definitely get the job done and has quite a service record in everything from Cadillacs to rental cars.
G8 GT-L76 6.0L V-8
If you've read this magazine for any measurable length of time, you've undoubtedly heard us bantering about the L76 intake paired with L92 cylinder heads. Oddly enough, up until now we didn't even have a vehicle in the United States that used this particular manifold. The good news is that not only do we finally get this mystical intake, we also get cylinder heads that fit the smaller bore-but with the same benefits of the L92-style heads, including the rectangular LS7-style intake ports.
In basic terms, the L76 is a natural extension of the LS2. They share a similar bore (101.6mm LS2, 101.3mm L76), and the same 92mm stroke, but there are also many differences that should be noted. First up is the addition of "Active Fuel Management," or Displacement on Demand, as it was originally termed. This system allows the deactivation of four specially provisioned cylinders through the use of particular lifters, oil channels, and tolerances on the camshaft lobes of those four cylinders. The L76 can thus transition from a V-8 to a V-4 and back again, with nearly seamless precision all but unnoticed by the driver. Additionally, this system increases fuel economy under low-load, low-throttle situations such as highway driving, but doesn't play a large role in city fuel economy. Currently, Holden does not have this feature activated on their L76s; however, the Pontiac model will reportedly have Active Fuel Management.
Next up is the option of variable cam-phasing. While the L76 currently in use in the Holden Commodore does not have the ability to change cam timing, the L76 truck variant here in the US does, which means we are likely to see it in the car relatively soon. This system works by metering the oil flow to the cam phaser, effectively physically advancing or retarding camshaft timing. Couple that with Active Fuel Management, and we have a V-8 that can not only pass upcoming stricter emissions standards, but also get incredible fuel economy.
Speaking of fuel, the L76 in the G8 is calibrated to unleash an astounding 362 hp on regular fuel. This is a dream come true for tuners, who will likely be able to wring over 40 hp by simply tweaking the fueling and spark to use high-test premium gasoline. Tuning, of course, leads us to another topic: the engine controller. As of press time, it appears the G8 will be sporting the relatively new Delphi E67 controller. This faster processor allows control of the Displacement on Demand and cam-phasing (if equipped) simultaneously, and adds a few needed input and output drivers, as well.
G8 GXP-LS3/LSA?
While there have obviously been no official on-the-record comments regarding the possibility of a 2009 G8 GXP, I don't think anyone doubts the likelihood. Sources inside both GM North America and GM Holden Australia confirm that an uplevel HSV Spec GXP is on the horizon for the second model year of the G8 (as has been the trend with Pontiac in the past, with the introduction of the Solstice, G6, and Torrent). Sources say the powerplant is still up in the air, though it's possible it will be the 6.2L 425-plus horsepower LS3, or, less likely, the 500-plus horsepower supercharged LSA slated to find its way into the new CTS-V. This would make the G8 GXP the ultimate Bimmer fighter, as it could probably take on the M5 in a head-to-head for roughly half the cost.
One thing is for sure: expect great things from this car, as well as a huge aftermarket following. The Grand Prix the G8 replaces was a 130,000-plus unit a year car line in its heyday. If the G8 comes even remotely close to that, the aftermarket will have no choice but to embrace the new offering. We'll keep you updated as we learn more.