2005 Cadillac CTS-V. Photos: General Motors. Click image to enlarge
by Richard Russell
Wixom, Michigan – General Motors is using horsepower and technology to prove it can compete with the very best the German car industry has to offer. Limited edition 2006 versions – the most powerful production models in the history of each division, have special hand-built engines accompanied by appropriate upgrades to the driveline and visuals.
The Cadillac STS-V boasts 440-horsepower and the Corvette Z06 a nice even 500. And in both cases, power goes to the rear wheels through a six-speed transmission, a brand-new automatic for the Caddy and a race-born Getrag manual box for the Corvette.
These amazing cars are the by-product of letting engineers go about their jobs without having to look over their shoulders at every turn for the legendary bean-counters. The instructions were simple – “we want to compete with the best: do what you need to”. For Cadillac it’s part of the push to re-invent a brand, and for Corvette, a bit of the same – establish a reputation as a serious performance vehicle. The competition for both comes from prestigious European marques that cost considerably more than the expected $100,000 (Cdn), $75,000 – $80,000 US tag expected to appear on the STS-V and Z06, making them a relative bargain in terms of bang for the buck.
4.4 Litre Northstar SC
And unlike some past “Motor City” attempts to take on the Europeans by merely squeezing in a monster motor, slapping on some big rolling stock and decals, the STS and Z06 positively bristle with suspension and brake upgrades more than capable of handling the new performance – and technology. High-tech reigns with everything from carbon fibre to more electronics than it took to put a man on the moon.
The STS engine bears a strong resemblance to the division’s Northstar V8, but is a unique casting with smaller bores to allow more room for cooling passages. The name and bore centres are all that remain of the normal engine. With a compact supercharger nestled between the cylinder banks, the 4.4 litre Northstar SC puts out not only 440-horses at 6,400 rpm, but 430 lb. ft. of torque at 3,600 – 90% of which is available from 2,200 rpm. With 120 more ponies and 115 lb.ft. more torque than its naturally-aspirated sibling, this twin-cam unit is among the world’s highest specific output production V8 engines. Caddy engineers are confident independent testing will reveal 0-100 km/hr times in less than five seconds – for a Cadillac!
Beneath the hood of the Z06 is the largest, most-powerful small block in Chevy history – a 7.0-litre or 427 cubic inch small block. In addition to 500-horses, it puts out 475 lb. ft. of torque. Utilizing racing technology developed over a half-century of competition and used in the factory race program to win at LeMans and in the American LeMans Racing Series, these engines use a distinct block casting, different front cover, oil pan, exhaust manifolds and CNC-ported cylinder heads. All internal components are unique lightweight units to allow a 7,000 rpm redline, including titanium valves and connecting rods and cast- aluminum pistons. Dry-sump lubrication is employed whereby oil is located in a separate tank rather than in a pan beneath the engine. This allows the engine to be lowered 2.5 cm in the chassis for a lower centre of gravity. Each of these high-tech engines will be hand-assembled by a single builder at GM new Performance Build Centre here. With a first gear ratio that will enable 100 km/h, look for 0-100 in less than four seconds, the quarter mile in the 11.5 second range at more than 120 mph and a top speed in excess of 190 mph. Like the STS-V, the Z06 is geared and powered to surpass the magic 300 km/hr mark, ensuring it will earn respect on the left lane of the Autobahn.
2006 Chevrolet Corvette Z06. Click image to enlarge
Everyone is on a diet for the new year, but the Corvette engineers went over the top. The Z06 is a rolling showcase for weight reduction. Aluminum, one-third the weight of steel, is used for the hydroformed body structure. Magnesium, one-third lighter than even aluminum, is used in the engine cradle, steering column support and some chassis components. Carbon-fibre, an intensely strong yet thin material made by heating synthetic materials, is used for the front fenders and wheelhouses. Balsa wood – while sounding a bit less technical, is the strongest wood for its weight in the world, in some aspects stronger than oak or pine. Balsa wood is sandwiched between carbon-fibre skins for the passenger compartment floor, cutting weight, sound and vibration while greatly contributing to structural integrity.
Passing the Caddy’s power to the rear wheels will be the job of a brand-new six speed Hydra-Matic transmission developed specifically for a wide range of rear drive applications. The STS-V may be first but look for this new unit dubbed 6L80, in everything from sedans to pickups in the coming months and years. One of the most technologically-advanced transmissions in the industry, it uses a 32-bit transmission controller and a variety of performance algorithm shifting programs developed during testing at the famed Nordschieffe, or North course at the Nurburgring in Germany. The STS-V is reported to have recorded lap times highly competitive with the best from Porsche, BMW and Mercedes.
The STS-V boasts a myriad of other changes to allow it to maximize the potential of the new engine – and be perfectly at home on high-speed European roads. Tires are bigger – 18-inches on the front and 19 inches at the rear. Brakes are obviously upgraded as well with bigger rotors, pads and callipers. The stabilizer bars and springs have been beefed up and the shocks re-valved. The steering is also quicker to match the higher performance envelope.
To differentiate the quickest Caddy ever, exterior enhancements include a polished-steel wire mesh grill, enlarged to allow more air intake required for the potent engine. The lower front fascia also is enlarged for increased cooling capacity for both the cooling system and brakes. At the other end, there is a new lower rear fascia designed to smooth airflow and extract heat. Between the new 10-spoke flangeless wheels are lower rocker covers that tie-together the new and lower front and rear fascias. The hood has a distinctive bulge to make room for the blower and the rear deck a more prominent spoiler. V-Series badging is subtle, yet evident in several locations.
Inside you’ll find hand-wrapped leather throughout, Olive Ash Burl wood and aluminum trim and “Tango Red” suede seat inserts. The distinct red also appears elsewhere throughout the interior.
In addition to the race-derived Getrag transmission, the Z06 uses a variety of upgraded components to permit safe use of the power. Bigger scoops behind the front wheels extract heat from 14-inch vented rotors clamped by six-piston red callipers and scoops ahead of the rear wheel feed air to 13.4 inch vented rotors, the same units used for the front of the C6 production car. The suspension has been appropriately re-tuned and the aerodynamics benefit from lessons learned in the race program.
The Z06 will be a limited production vehicle, designed and aimed at buyers who intend to use it on the race-track. It will even be covered by the factory warranty for occasional use for this purpose!