Pontiac engineer Tom Goad is irrevocably hooked on the 2+2 sports coupe in the Pontiac lineup, and has been for years. He calls the Firefox the latest tangible evidence of his never-ending quest for faster and better-handling Firebirds. Goad's official title is manager of special vehicle engineering, but he makes no secret of the fact that he's the Santa Claus of Pontiac's toy shop. Firefox is just one of several studies aimed at probing uncharted realms of the Firebird's performance envelope.
Firefox's origins date back more than three years. in preparation for the '89 20th Anniversary Trans Am model, Pontiac chiefs held a brainstorming pow-wow. The ideas that surfaced ranged from cloisonne' escutcheon plates to massive horsepower injections. Two proposals that didn't make the cut for production anniversary T/A were a six-speed transmission and independent rear suspension (IRS). The original Firefox surfaced three yearts ago with insidiuous black paint, fat footwear, and plenty of horsepower. Son of FF was built off-campus by TDM Technologies of Livonia, Michigan, an automotive engineering support firm. It wears jade green paint over standard '91 sheetmetal with a number of interesting alterations from production specifications embodied within.
Let the guided tour begin under the hood. The engine is a 5.7-liter V-8 wit hseveral horsepower helpers. Bartz aluminum cylinder heads provide a small weight reduction, larger valves, and a higher (10.5:1) compression ratio. To boost airflow, intake manifold runner tubes have been increased from 1.375 to 1.75 inches in diameter. The exhaust headers are standard Edelbrock ready-to-wear components. Valve timing was specifically tailored to this engine and roller-tipped rocker arms have been added. Fuel injectors have a larger than normal flow capacity. The bottom line is a substantial increase in both power and torque. The horsepower curve peaks at 328 horsepower and maximum torque is 395 pound-feet at 3500 rpm. For the statisticians in the audience, the net increases are 37 and 16 percent, respectively.
Firefox's ZF six-speed transmission was pirated from the Corvette. Carrying that idea to the logical extreme, this car also boasts a full Corvette independent rear suspension. The all-aluminum rear axle assembly nestles in place quite nicely. A compact muffler is located just behine the 3.91:1 limited-slip differential, and there's a small fuel cell packaged in what used to be the luggage well. Firefox also has provisions for a monolithic catalyst, but the active ingredients are missing in this particular prototype.
To pass the extra power to the pavement, tires and wheels have been upgraded in kind. Firefox's fenders are overflowing with P275/40ZR17 Goodyear Eagle ZR40 tires monted to 9.0-inch BBS three-piece wheels.
As you should expect, Pontiac's toy turned in an impressive performance report card at the test track. It's quite capable of smoking its fat rear tires, but with restraint at the starting line, we minimized wheelspin to clock a 0-60 time of 5.2 seconds and quarter-mile results of 13.5 seconds at 103.2 mph. That's a tick quicker than our first test of the 300-horsepower '92 Corvette! Handling test scores are also in the thick of pure sports-car territory. On the skidpad, Firefox demonstrated the nimble balance of a ballerina, while posting a limit adhesion of 0.93 g. It danced its way through the 600-foot slalom course in 67.0 mph, just slightly off the '91 ZR-1 Corvette's 68.6-mph performance.
The Firefox is also a ball to drive in the real world if you can stand the rough edges of a high-mileage mule. Filter out the grating sound of tires rubbing against fenders, the incessant rumble of a half-civilized exhaust system, the jolt of stiff suspension calibrations, and the rattle of components unaccustomed to their new working environment, and you've got a Trans Am with moves to match its racy name.
It's no secret that an updated Firebird is headed our way for the '93 model year. When asked if the fruits of the Firefox investigation will make production, Tom Goad responds like a Russian diplomat, "Well, they could. I wanted an IRS Firebird to demonstrate the inherent advantages of such a system. After you've lived with axle hop on acceleration and braking, it's great to hace a car that doesn't go crazy over bumps. The ultimate packed is IRS with our new front suspension. That will probably be our next step." This is the beauty of running your own automotive toy shop. Shortcomings from the assembly line are easily rememdied."
GENERAL/POWERTRAIN
Body style:.......... 2-door, 4-passenger
Vehicle configuration:......... Front engine, rear drive
Engine configuration:.......... V-8, OHV, 2 valves/cylinder
Engine displacement, ci/cc:.......... 350/5736
Engine power @ rpm (SAE net):.......... 328 hp @ 4500 rpm
Engine torque @ rpm (SAE net):.......... 395 lb-ft @ 3500 rpm
Transmission:......... 6-speed manual
Axle ratio:.......... 3.91:1
DIMENSIONS
Test Weight:.......... 3670 lb
Weight distribution, f/r:.......... 57 / 43%
Wheelbase, in/mm:.......... 101 / 2566
Length, in/mm:.......... 195.1 / 4955
Curb weight, lb:.......... 3477
Fuel capacity, gal:.......... 10.0
CHASSIS
Suspension, F/R:.......... independent, independent
Steering:.......... Recirculating ball, power assist
Brakes, F/R:.......... Vented discs, discs
Wheels:.......... 17 x 9.0 in.
Tires:.......... P275/40VR17 Goodyear Eagle VR40
PERFORMANCE
Acceleration, 0-60 mph:......... 5.2 seconds
Quarter-mile, sec/mph:.......... 13.5/103.2
Braking, 60-0, ft:.......... 135
