http://89tta.turbobuicks.net/ttahist.htm
They are rare and are worth a few bucks.
Some key details:
Originally conceived by Bill Owen of Pontiac, the 20th Anniversary Turbo Trans Am project was outsourced to PAS, Inc., an engineering firm led by Jeff Beitzel. Beitzel and his team did most of the TTA development work. The V6 turbo engines were built by PAS at their 40,000 square foot City of Industry, CA plant. From there, they went to GM's plant in Van Nuys, CA to be installed into GTAs on the F-Body assembly line. The cars were then shipped back to PAS for final assembly, testing, and quality control. Incidentally, the GTA chassis were selected at random, thus there is no correlation between VIN number and production sequence number. The actual number of cars to be produced had ranged from 500 to 2,500 until GM finally settled on 1,500. In all, a total of 1,555 Turbo TAs were manufactured.
You can see how these would be collectable.Technical Highlights
What makes the 20th Anniversary Turbo TA so special is that it is a complete mechanical package, and not just some tape stripes. Starting with the engine, Pontiac borrowed Buick's 3.8 liter (231cid) V6 turbo powerplant from the fabled 1986-87 Grand National. Some difference exist between the TTA motor and the GN version. Different heads were necessary in order to squeeze the motor between the strut towers. These heads, adapted from the transverse FWD version of the 3.8 liter motor, have the added benefit of improved exhaust flow and combustion chamber design. Subsequently, different pistons were required in order to maintain combustion chamber volume. Other changes to the TTA motor are a cross-drilled crank, larger 12 fin/inch GNX-style intercooler in place of the GN's 10 fin/inch design, specially-designed stainless-steel headers, higher-pressure Bosch 237 fuel pressure regulator, and a recalibrated engine control module.
Mark Grable, writing in the March 1989 Motor Trend, noted the Turbo Trans Am's "250 horses...seem much stronger than run-of-the-mill horses." The reason is simple. Although Pontiac officially rated the engine at 250 HP, in reality it developed an honest 301 HP on the GM dyno.
The Turbo TA came with the rare 1LE racing brake package, which upgrades the front discs to 12 inch police rotors, Corvette twin piston aluminum calipers and semi-metallic pads. These brakes are virtually fade proof, and were installed to legalize the 1LE package for Firehawk endurance racing. The rear discs were also increased to 12 inches in 1989 and use Corvette single piston calipers. All of the brakes on the car are of a quick change design, and pads can actually be changed in 30 seconds.
The only mid-year change made to the Turbo TA during the entire production run was a redesigned turbo inlet tube. The redesigned plastic tube was more durable, and had a clamping rib on either end to keep the hoses attached more securely. Other production changes in 1989 affected the Turbo TA and F-bodies in general. As an example, in March 1989 GM switched from glass to Lexan T-tops in order to save weight. However, the Lexan tops had severe problems with scratching and cracking, and GM had to replace most of them under warranty. During the 1990 production run GM switched back to glass T-tops after having so many problems with the Lexan ones.
Transcribed C/D article, written by Csaba Csere:
http://www.gtasourcepage.com/8920thTACDReview.html
13.4 @ 101 is properly quick for 1989. In fact, it is only a tenth or two and a mph or two away from LS1 F-body performance. 10 years earlier. That is particularly impressive when you remember how far superior the LS1 stuff was to anything, say, Ford had when it originally hit the streets.Our test car scorched the drag strip with a 0-60-mph blast of 4.6 seconds and a quarter-mile run of 13.4 seconds at 101 mph. That means, as we go to press that the turbocharged Trans Am is the quickest 0-60 sprinter available in any US production-car showroom – at any price.
Now about that 4.6 0-60:
Different heads, different pistons.Achieving such stunning times doesn’t require high-rpm clutch drops or other test-track trickery. Just pop the automatic transmission into Drive, hold it with the brake while you raise the engine speed to 2100 rpm, release the brake, and floor the throttle. The turbo Trans Am instantly shoots forward like a runaway rocket sled. The roar from the under the hood builds as the boost gauge needle dances around the 16.5-psi mark. And the Turbo Hydramatic T200R4 four-speed automatic snaps off crisply at just over 5000 rpm – without a nanosecond of lost thrust. The rush is so strong that the turbo Trans Am reaches 130 mph in just 30.2 seconds.
The engine providing the motivation for these fireworks is basically the same turbo V6 used in Buick’s Regals. The most significant change is a new set of cylinder heads, borrowed from the transverse-mounted version of the 3.8-liter six that GM uses in many of its front-drive cars. Pontiac adopted the new heads because they fit more easily within the narrow confines of the Trans Am’s engine compartment. In addition, the new heads provide better exhaust flow and have a more efficient combustion-chamber shape than their predecessors.
A new set of pistons match the cavities in the new heads to preserve the engine’s 8.0:1 compression ratio
Ironically, both the brakes and handling (on rough roads) were not properly sorted out in the test car that Csaba had. I don't know if it was preproduction but I sure hope it was.Pontiac’s output claims for the V6 are exceedingly modest: 250 hp at 4400 rpm and 340 pound-feet of torque at 2800 rpm. Judging by our performance figures, we estimate that the engine produces closer to 300 hp.
Also all this stuff added $9k to a Trans Am GTA sticker.
Anyway, these are cool and rare and special. I saw one once at New England Dragway.