Chevrolet officially took the wraps off its all-new midsize 2002 TrailBlazer last week at the Texas State Fair. It goes on sale next spring.

The TrailBlazer slots into Chevrolet’s lineup ahead of the current Blazer, which will continue in production for the next year or two.

No vehicles have been available for driving yet, but the TrailBlazer is so radically new it deserves a close look.

TrailBlazer will share its platform, powertrain and some body panels with the 2002 GMC Envoy and 2002 Oldsmobile Bravada. Two-wheel- and four-wheel-drive versions are offered. Electronic traction control is optional on two-wheel-drive models.

All three vehicles will showcase General Motors’ newest engine, the Vortec 4200. This is a 270-horsepower, 4.2-liter, all-aluminum inline six-cylinder engine with dual overhead cams and four valves per cylinder. An inline six is a radical departure from the V6 and V8 powerplants that normally inhabit such vehicles, but GM said it chose to develop this engine because of its inherent smoothness. Plus, they say they are able to attain the fuel economy of a six with the power of a V8.

Six-cylinder engines were long a staple of Chevy trucks. The first one made its debut in 1929, and 1985 was the last time one was available in a truck. Those engines were a far cry from this one, which uses state-of-the-art design and electronics. Engines like this are found mainly in imported cars such as BMW.

The Vortec 4200 has variable valve timing, coil-on-plug ignition, direct-mounted accessories and an electronic throttle control often described as a “drive-by-wire” system. The throttle pedal activates sensors that then tell the throttle on the fuel-injection system what to do. GM points out that the electronic throttle also provides cruise control and traction control functions. Engine mounts filled with hydraulic fluid replace traditional solid-rubber bushings to keep engine vibrations from resonating throughout the vehicle.

Compared to the Blazer, the TrailBlazer’s 113-inch wheelbase is 6 inches longer, and overall length is up 8 inches. It is nearly 5 inches wider, and all interior dimensions have been increased as well. Towing capacity has jumped from 5,000 pounds to 6,400 pounds.

Inside, the front seats have 4-way adjustable headrests and can be equipped with memory functions as well as three levels of heating. The split-folding second seat has longer, wider and taller seat cushions. No third seat is offered, although extended-wheelbase versions are planned for 2003.

Dual-zone temperature control is standard and rear-seat air conditioning will be offered on premium models.

TrailBlazer still utilizes a body-on-frame design, but the frame makes greater use of hydroformed rails that were first used on the 1998 Silverado pickup. The new frame is both lighter and stiffer.

In order to yield carlike handling, the front suspension uses dual wishbones and coil springs. It is the same for both two-wheel and four-wheel drive. In four-wheel-drive models, the transfer case is bolted to the engine rather than the frame and one of the front drive shafts passes through the oil pan.

The rear suspension is a five-link, solid-axle design very similar to that used on the larger Tahoe. Coil springs are used here, too, to improve ride quality. Chevrolet said it wanted ride and handling more like a touring sedan than a truck. We’ll have to wait for a test drive to see if they met their goal.

Rack-and-pinion power steering replaced the recirculating ball type on the old vehicle and should provide much-improved steering response and feel.

Disc brakes, substantially larger than the current Blazer, are used on all four wheels. They are vented for better cooling. Anti-lock is standard.

Sixteen-inch wheels are standard but 17-inchers are optional. All wheels will be cast aluminum to save weight.

Safety items include dual-stage front rbags, seat-mounted side-impact airbags and seat-mounted, three-point safety belts for all occupants.

Vehicles should be available for limited driving in about six weeks, at which time I can report driving impressions.

To get in touch with Tom Strongman call (816) 234-4349 or e-mail: strongmn@kcstar.com.

SPECIFICATIONS:

Engine: 4.2-liter, 6-cyl.

Transmission: automatic

Two- or four-wheel drive

Wheelbase: 113 inches

Curb weight: 4,442 lbs.

Base price: not avail.

As driven: not avail.

Mpg rating: not avail.