Chevy K5
Chevy K5
Click image to enlarge

by Greg Wilson

Milan Raceway, Michigan – Officially, it was called the General Motors Special Vehicles Media Event – unofficially, it was the GM “Toys Test” – an auto enthusiast’s orgy of over 50 production-based concept vehicles available to be driven for the first time. I was invited, along with approximately 50 other auto journalists, to take one or all of them for a brief, but revealing drive around the scenic Michigan landscape.

Six of the vehicles, the Buick LeSabre Ultra, Cadillac Escalade show truck, Pontiac Sunfire Piranha, Chevrolet Blazer ZZ 4.3, and a 742 horsepower Corvette, had never been seen before. There were just too many vehicles to drive in the space of a few hours, so I chose the most interesting vehicles for this report. Unfortunately the 742 horsepower Corvette was not available for test-driving, but I was able to bring back some photos of this awesome machine!

Here are some firsthand driving impressions of some cars and trucks you might see in GM showrooms in the next few years..


Chevrolet Silverado SS


Chevy SST
Click image to enlarge

A cross between a Corvette with a Silverado pickup, the Silverado SS is a four passenger, four-door pickup with a 6.6 litre OHV aluminum LS1 (Corvette) V8 under the hood that produces 480 horsepower at 6000 rpm and 475 lb-ft. of torque at 4800 rpm. Like the Corvette, it offers a short-throw six-speed manual transaxle mounted at the rear which delivers the power to the rear wheels. The Silverado SS has a four-wheel independent suspension and air shocks that allow the driver to adjust the ride height for highway cruising or light-duty off-road use. It also offers four wheel disc brakes with 14 inch rotors, dual 3-inch exhaust pipes, and 20 inch wheels and tires in the front and 22 inch wheels and tires at the rear.

Chevy SST
Click image to enlarge

Inside there are four bucket seats with carbon-fibre inserts, a blue electroluminescant instrument cluster, four-point safety harnesses, a Hurst-style shift lever, and a Corvette steering wheel. The Silverado’s sleek styling is enhanced by an integrated cab and box which have a smooth, moulded one-piece appearance.

On the road, the Silverado SS is rough and noisy – the big V8 throbs and vibrates, the exhaust note is loud and racy, the ride is stiff, and the manual shifter has short, notchy throws – truly the Corvette of pickups. GM will have to smooth out a few wrinkles before this truck is ready for production, but the concept of a sport truck with the character of a Corvette will certainly appeal to urban cowboys everywhere. And in my opinion, this is the handsomest truck that I’ve seen from Chevrolet – the complete opposite of the Avalanche!


Chevrolet K5


Chevy K5
Click image to enlarge

Remember the full-size, two-door Blazer with a removeable top? It was produced from 1969 to 1995, then was replaced by the four-door Tahoe. The Chevrolet K5 concept truck offers a sneak peek at the possible future of a new two-door Tahoe. The K5 features an open-air rear cargo bed with removeable carbon-fibre top. Though it appears to have two doors, the K5 has an additional two rear door panels which open out to the rear by almost 180 degrees to allow access to the two rear seats. The rear split folding seats fold down flat to provide a (carpeted) load floor that is six feet long from the tailgate to the front seatbacks.

The K5 has more aggressive styling than the Tahoe, with such features as fender flares, aggressive lower body cladding, nickel-coloured grille with a ‘milled’ Chevy bow-tie emblem, and 18 inch five-spoke Budnik wheels on P285/60R-18 inch Goodyear Eagle tires. Powered by a modified version of GM’s Vortec 6.0 litre V8 engines which develops 440 horsepower at 5700 rpm and 450 lb-ft of torque at 4700 rpm, the engine is mated to a four-speed automatic transmission.

Since it has a shorter wheelbase than the four-door Tahoe, I found the K5’s ride choppier, but the turning circle is tighter. The powerful 440 horsepower V8 has lots of torque which translates into rear wheelspin when the road is wet, as it was on the day I test-drove it. Like the Silverado SS, the K5 is loud, and a considerable amount of vibration enters the cabin – I had to keep reminding myself that this is a one-off concept vehicle that’s not quite ready for production. The attractive interior, which is finished in grey and trimmed with graphite leather and ‘carbon fiber’ trim is similar to the Avalanche’s interior. Without the rear canopy, the rear passengers are exposed to the Sun or rain, as the case may be, and there’s nowhere to store the canopy when you’re not using it – the K5 would be a great vehicle if you live in San Diego, but in Vancouver you’d be afraid to leave the canopy at home!

Hummer H1 Vortec 8100

Hummer H1 Vortec 8100
Click image to enlarge

The current Hummer comes with a 170 horsepower 6.5 litre turbo-diesel engine – imagine a Hummer with a 340 horsepower 8.1 litre Vortec V8 engine! Now that GM owns Hummer, it’s a relatively simple matter to add a more powerful gasoline-fueled engine to the heavy-duty Hummer – a vehicle that was originally designed for the U.S. Army by AM General and which saw duty in the Persian Gulf war.

The 8.1 litre V8 engine develops 340 horsepower at 4200 rpm and 455 lb-ft. of torque at 3200 rpm. The engine is teamed with the Hummers TorquTrac4 traction control system and four-speed automatic transmission. In addition, the fully independent suspension was tuned by Rod Hall, winner of 16 Baja 1000 desert races – it includes large 3.5 inch diameter shocks (!), increased wheel travel of more than three inches, new front sway bars to improve steering, and lower spring rates for an improved ride.

Inside is a Delphi Integrated Navigation Radio with full map navigation and a CD ROM player and colour display screen, and a Global Positioning System for real-time location tracking. There’s also a link for laptop computers and palm devices. The H1 Alpha is also equipped with Raytheon’s Night Vision and head-up display which allows drivers to see objects three to five times farther than the low-beam range.

Hummer H1 Vortec 8100
Click image to enlarge

On the road, I found this Hummer to be quieter than the diesel model, but not nearly as quiet as a Chevy Silverado with the 8.1 litre engine – most likely due to less sound insulation. The bigger engine is more powerful and responsive than the diesel engine and makes the H1 Alpha a more pleasant vehicle to drive in both city and highway situations – however, the H1 Alpha retains the crude, utilitarian feel of an army vehicle. Though the interior has been improved, the small, round instruments are scattered around the dashboard, and controls are hard to see. The high centre console which is about three feet wide (where the driveline is located), separates the four passengers, and makes this huge vehicle feel cramped! The ride is stiff, brake pedal effort is rather high, but steering effort is surprisingly low. There’s no doubt the Hummer H1 Alpha is a rugged, capable off-road vehicle, but it’s still a long way from the sophistication of a Suburban or Tahoe. I guess that’s where the new Hummer H2 will fill the gap..


Pontiac Grand Prix G8 AWD

What do you get when you add a 350 horsepower 5.7 litre V8, Versatrak all-wheel-drive, and Goodyear 255/40ZR-19 inch tires to a Pontiac Grand Prix? – the Grand Prix G8, a high-performance mid-sized sedan with superb handling and traction. With the 350 horsepower LS1 Corvette engine, the Grand Prix G8 does 0 to 60 mph in 5.5 seconds. It features the Versatrak on-demand all-wheel-drive system, custom-designed 19 inch X 9.5 inch wheels, 3 inch exhaust pipes and dual exhausts, a suspension lowered by one inch, and larger rotors on all four discs.

The aggressive exterior offers ‘boisterous’ wheel flares, hood scoops, a GTO style spoiler and hood tachometer gauge.

The LS1 engine gives the Grand Prix G8 instant torque, but there’s little wheelspin as the Verstrak sends power to the rear wheels as the front wheels slip. The stiffer suspension and low profile tires make for a stiff ride, but handling is superb, and the cornering limits are extremely high. The Versatrak system provides greater stability when cornering in the wet, but the Grand Prix G8 is too low and the tires are too wide to be of any use in winter or off-road conditions. This is strictly a performance sedan that could rival high-performance European sedans in handling and acceleration.


Cadillac Escalade twin-turbo

GM is already saying that the new Cadillac Escalade is the most powerful SUV in the world – imagine a twin-turbocharged Escalade with 580 horsepower and 580 lb-ft. of torque! This concept vehicle was perhaps the closest to production in terms of refinement – GM took a 6.0 litre V8 engine, added a Corvette camshaft, reworked the heads, and added twin Aerodyne turbos and intercoolers and squeezed it into an Escalade engine bay to provide unprecedented horsepower in an SUV. The Escalade Twin Turbo also has dual radiator cores, oil and transmission coolers, power steering cooler, rear positraction, and a 3 inch stainless steel exhaust system. It sits on Goodyear P275/45HR-20 inch Eagle GT 11 tires on 20 inch X 8.5 inch wheels. The modified suspension has been lowered by 1 inch in the front and 1.5 inches at the rear. Inside is a Shale leather interior, video/TV screen and DVD player.

The Escalade Twin Turbo is perhaps the ultimate in SUV excess – all the luxury, all the power, all-wheel-drive, all the time. Though I can’t imagine what the gas mileage is for the Escalade Twin Turbo, this beast goes very quickly for a heavy SUV. There’s not much turbo lag, and vehicle dynamics are amazingly controllable for a tall, massive vehicle like this. Unlike other concepts I drove, this one was reasonably quiet and easy to drive. In the battle to create the ultimate luxury SUV, automakers like Lincoln, BMW, Lexus, Mercedes-Benz, and Cadillac are upping the horsepower ratings to astounding new heights – with 580 ponies under the hood, the Escalade Twin Turbo may just top the horsepower charts if GM chooses to put it into production.

Pontiac Sunfire

Pontiac Sunfire Piranha
Click image to enlarge

The sporty compact/boulevard racer market is really taking off, and with relatively little effort, GM could add this performance option package to the current Sunfire. The Pontiac Sunfire concept car has a supercharged 2.4 litre DOHC 16 valve four cylinder powerplant that develops 190 horsepower at 5800 rpm and 205 lb-ft. of torque at 4000 rpm. That compares to the current non-supercharged motor which offers 150 horsepower at 5000 rpm and 155 lb-ft at 4400 rpm. The supercharger is an Eaton Series 45 with a maximum boost of 5 psi.

The concept Sunfire features a ground effects package that includes a front air dam, rocker mouldings, and rear skirt. Aggressive exterior features include ram-air hood scoops, rear wing and spoiler, carbon-fibre exterior mirrors and quad exhaust pipes. Inside is carbon-fibre trim on the dash and door handles, different-colour seat inserts in the sport seats.

Pontiac Sunfire Piranha
Click image to enlarge

The 2.4 litre supercharged engine has much better off-the-line response than the standard 2.4 litre four cylinder engine, but there is that characteristic supercharger whine when accelerating. The supercharger offers better throttle response at all speeds, unlike turbos which lag at slower speeds. The Sunfire’s suspension is stiffer, but not uncomfortable, and the steering effort is also stiffer for a sportier feel. Handling is flatter than the standard Sunfire but there is some trade-off in ride. Though the Sunfire platform is getting on in age, a performance package like this could inject a little life into the Sunfire, and help it compete with popular imports like the Civic, Integra and Protege.


742 horsepower Tiger Shark Corvette


Tiger Shark Corvette
Click image to enlarge

I didn’t get to drive it, but this sharp-looking Corvette was inspiring enough to make me wonder if it’s going to become a production vehicle. GM bored out the Corvette’s LS1 V8 to 7.0 litres (427 cu. in.) and added a Vortech ‘T’ supercharger – that produces an amazing 742 horsepower at 6000 rpm and 690 lb-ft of torque at 5700 rpm. The Tiger Shark Corvette has a six-speed Borg Warner manual transmission, electronic throttle control, a modified independent suspension, large Brembo racing brakes (14 inch front/12 inch rear), 18 inch wheels, Goodyear F1 Fiorano tires, and a Tiger Yellow paint job and black leather interior. Even if it was built as a limited production model, the Tiger Shark would certainly become an image leader for Chevrolet and GM. I say, build it!


More GM concepts!

Click the images to enlarge

Chevrolet S10 four-door
Chevrolet S10 four-door
35th anniversary Camaro
35th anniversary Camaro

Cavalier Technic
Cavalier Technic
Buick leSabre Ultra
Buick leSabre Ultra


Chevy Bruin

Connect with Autos.ca