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Old 12-16-2008, 06:27 AM
06RangerSTX 06RangerSTX is offline
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Default The Flying Bread Box!

GM Powertrain’s Road Racing Chevy TrailBlazer
No, we're not kidding. Those guys at GM Powertrain have built a TrailBlazer SUV to compete on the road-racy circuit. It sounds like the equivalent of taking a brick to a gunfight, but hold your final opinion until you read the story. After all, we are talking about engineers with access to the world's largest parts bin.

With access to all of the swoopy bodies that the General has (think Corvette, GTO, Cobalt, Solstice), why a TrailBlazer? To elicit that kind of reaction, for one. To prove that a vehicle with the aerodynamics of a breadbox can be competitive, for two. And because it was the best fit for the chassis that the Powertrain guys had available, for three. You see, this was an after-hours, budget-conscious project-a labor of love, so to speak.

The first problem Manufacturing Engineer Dave Caplan and his team had was finding a class the TrailBlazer would fit into. “We built the truck to fit within the E Modified race class for SCCA Solo II autocross," Caplan explained. “This is the only legal class we could fit into given our engine/transmission/chassis combination."

With the venue chosen, work began. The chassis is based around an ex-race Chevy S10. The team updated the tubular frame with a fully adjustable, short/long arm independent front suspension with AFCO double-adjustable coil-over shocks and an adjustable stabilizer bar. Out back an 8.5 inch 10-bolt axle is suspended by a four-link with two more AFCO adjustable monotubes. The truck's ride height is fully adjustable as well. The brakes are Wilwood discs up front and production TrailBlazer discs out back. To help achieve a 55/45 percent weight bias, engine location was moved back about five inches.

Speaking of engines, the TrailBlazer's is a doozy-a production LS7 from the Corvette Z06. Other than CNC-ported heads, a custom grind cam (a “575 horsepower" grind according to Caplan) and one-off exhaust headers, the 427 cubic inch screamer is stock. The Powertrain gang even retained the production Corvette computer. A T-56 six-speed transmission and bellhousing were borrowed from the now-defunct Chevy SSR. The SSR bin also donated a driveshaft, which was shortened to fit the chassis.

As for the body, most of it is genuine TrailBlazer EXT steel-they've just been modified a bit to fit the tube chassis. OK, modified a lot; the only parts that were not massaged to fit were the doors. The panel bracing was all custom-made, as were the interior block-off panels and the seat brackets. As befits a work-in-progress, the paint is black primer; final bodywork and color will be addressed over the winter.

So, how does this parts-bin racer run? The Powertrain team has not taken the TrailBlazer to the track yet, but a rather proud Dave Caplan said the truck will spin the street Goodyear F1s in third gear at a loafing 1,500 rpm. To which we say, yikes.

Caplan and his team unveiled the TrailBlazer at the Woodward Dream Cruise this past August. “We attached a manufacturer's license plate to the back, so we were "legal" to drive on the street," said Caplan. “We cruised all the way from the GM Tech Center in Warren to Woodward Ave. in Royal Oak, then we cruised all afternoon on Friday followed by a full day of cruising on Saturday. Reliability is not an issue."

Neither, apparently, is the fun factor. All we gotta say is, those SCCA boys will get an eyeful when they see this flying breadbox tearing up the E-Modified course next season.

Frame: Tubular, based on a 2003 S10 race truck
Front Suspension: Fully adjustable SLA with AFCO double adjustable monotube coil-over shocks, adjustable stabilizer bar
Rear Suspension: Fully adjustable 4-link with AFCO double adjustable monotube coil-over shocks
Brakes: Wilwood front disc with hard-mounted 4-piston calipers, production TrailBlazer rear disc with 1-piston floating calipers
Race Wheels and Tires: 16 x 12 front/16 x 13 rear on Hoosier slicks (23.5 x 12 front/23.5 x 12.5 rear)
Street Wheels and Tires: Production Corvette Z06 wheels and Goodyear F1 tires
Other Items: 14:1 power rack and pinion steering, adjustable ride height, engine set back 5", 55/45 weight distribution, 2,600 pounds total weight

Engine and Drivetrain
Engine Type: Corvette Z06 LS7, 427 cubic inches
Modifications: CNC-ported cylinder heads, custom-grind camshaft, custom exhaust manifolds
Control Module: Production Corvette Z06
Other Items: Custom alternator bracket, dynamometer-ready wiring harness with data collection sensors
Transmission: T-56 6-speed and bellhousing from Chevy SSR
Rear Axle: 8.5" 10-bolt with 3.42 gears and Eaton limited slip differential
Driveshaft: Shortened and balanced Chevy SSR

Sheetmetal: front fenders, doors, hood, hatch, from TrailBlazer EXT; roof, door rings, radiator support and headlight mount from standard TrailBlazer; front bumper and grille from TrailBlazer SS
Modifications: Quarter panels fabricated from standard TrailBlazer and TrailBlazer EXT quarters; custom-made rear hatch support, rear body, and bumper bracing; custom interior close-out panels; custom-made Lexan windshields and windows
Paint: Sinister Black primer
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Old 12-17-2008, 05:32 PM
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admin admin is offline
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Posts: 127

Man I can't wait to see this "breadbox" toast the competition! No pun intended.

..and another great find!

We'll add these to our truck database.
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Old 12-17-2008, 05:44 PM
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Barbell Company Barbell Company is offline
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Two wheel drive I assume?
Adam Auerbach


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Old 12-17-2008, 07:24 PM
06RangerSTX 06RangerSTX is offline
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Yeah, I think it was two-wheel drive...
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Old 06-06-2009, 06:58 PM
ToyComa ToyComa is offline
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Join Date: Jun 2009
Posts: 6

sorry i am so late to the party but, they make a 2 door trailblazer? i have never ever seen one before. Looks wicked.
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"We're going road racing in a truck. That's so wrong." - Gale Banks