Pontiac turned the traditional definition of "musclecar" on its head with the introduction of the '89 Turbo V-6 20th Anniversary T/A when it took the adage "big engine plus intermediate car equals fun" and turned it into "efficient computer-controlled turbo V-6 plus ponycar equals wow!"
Buick began experimenting with turbocharged V-6 engines, stuffing them into its cars in the late-'70s. It wasn't until the 231-cid turbocharged V-6 found its way into the Grand National with its on-board computer-controlled sequential fuel injection that a legend was born.
The V-6 produced 200 hp and 300 lb-ft of torque in '84, but by '86, revisions to the block and the addition of an intercooler for the turbo-boosted power to 235 hp-276 hp in the GNX. Looking back, we realize these later engines were severely underrated and actually produced over 300 hp.
When the U.S. automotive market began to acknowledge the potential for forced-induction and small-displacement engines in the '80s, a V-8 was no longer necessary to achieve track supremacy and bragging rights. Buick's turbo V-6 could clean the clock of its contemporary competition, and did so publicly in many major automotive magazines.
By the late '80s, everybody was still catching their breath from the turbo Buicks' performances, and the Trans Am had a birthday coming up. Bill Owen of Pontiac conceived the perfect celebration for such a milestone-a limited edition 20th Anniversary Trans Am, powered by the 3.8L turbo Buick V-6 (plans for an all-aluminum V-8 fell through).
The project was outsourced to PAS Engineering of Van Nuys, California, which received GTAs from Pontiac's Van Nuys assembly line, and then converted them at its Industry City, California, facility.
Under The Hood
The TTA's Buick mill is rated at 250 hp, thanks to a more efficient 12-fin intercooler from the GNX, stainless-steel headers, recalibrated engine controls, and a high-pressure Bosch 237 fuel pressure regulator.
On an interesting note, the Buick heads wouldn't allow the engine to fit between the strut towers, so a solution was found within Pontiac. The existing Bonneville 3800 Series-I V-6 cylinder heads increased clearance and offered superior flow over the Buick heads. As a result, a new hypereutectic piston design was used, while Buick's cast rods and nodular-iron cross-drilled crankshaft were retained.
A Garrett T3 turbo delivers up to 16.5 psi of boost into a 75.5mm MAF and 58mm throttle body. From there, the aluminum intake manifold ingests the air, where it combines with fuel introduced by Bosch 28-lb/hr injectors. The camshaft is a hydraulic-roller, ground to 192/196-degrees duration and 0.409/0.434-inch lift. It allows the air/fuel mixture to enter the chambers via the 1.71-inch intake valves, and the spent gases to exit via the 1.49-inch exhaust valves, actuated by 1.65:1 rocker arms. Compression is a boost-friendly 8.0:1.
Even the plug wires were ...
Even the plug wires were special.
Once the energy from the fuel is used, the combustion gases are sent to the Garrett T3, where they spool the turbo and generate boost. Then the gases clear out through a 2.5-inch exhaust with a crossover muffler and split exit tips. The engine delivers power to the wheels through a 200-R4 trans with a lockup torque converter and a 3.27-geared 10-bolt rearend.
In stock trim, the TTA was capable of 13.5-second quarter-mile e.t.'s.
Wait, There's More
The 20th Anniversary Trans Am was an engineered package of upgrades, not just a hot engine. The 10.5-inch brakes were replaced with the famed 1LE racing brakes, with 12-inch police-package rotors in front and 11.7-inch rotors in the rear. Corvette twin-piston binders up front and single pistons in the rear chomp down on the large rotors to bring the T/A to a halt from 60 to 0 mph in 139 feet, according to Pontiac. Underneath the Bird, 36mm front and 24mm rear sway bars keep cornering flat and aid in providing 0.86 g of lateral grip in concert with the 16x8-inch wheels and 245/50VR16 Goodyear Gatorback tires.
Exterior badges notify curious onlookers that this isn't your typical GTA. The Indianapolis emblems are a tip of the hat to it being used as the Indy 500 pace car. Inside is another callout on the map pocket, a boost gauge, and the only music-provider-an AM/FM cassette player. The CD player wasn't available on the TTA.
With the only options being a choice of interior upholstery and T-tops or not, most TTAs stickered at around $31,000 in '89 money-before dealer "market adjustment" markup.