In 1990, stepping into a well-optioned Pontiac Grand Prix STE Turbo felt like stepping into a futuristic cockpit. Steering wheel audio controls, gauge-flanking switch pods, a digital driver information center, and a head-up display projected directly into your field of view made it clear this wasn’t an ordinary sedan – a point driven home by the boost gauge hinting at the turbocharged V6 beneath the hood.
It looked like the dawn of Pontiac’s high-tech era, yet just months later, the company abruptly pulled the plug on the car’s turbo drivetrain.
Pontiac Turned Its First Grand Prix Sedan Into A Spaceship
1990 Pontiac Grand Prix STE Sedan front quarterBring a Trailer
Pontiac’s STE Turbo wasn’t a concept car but instead arrived at an important moment for the company’s Grand Prix badge. This was one of the company’s longest-running nameplates, and from its debut in 1962 through to 1989, it had always been exclusively a two-door machine.
To spruce up the vehicle for the new decade, Pontiac added four-door LE and STE versions in 1990, with STE standing for Special Touring Edition. And this was a badge that was well known in performance circles, related to the company’s famous 6000 STE performance sedan.
Still, Pontiac had no intention of making this new car look like any anonymous family sedan. It gave the STE distinctive full-width front and rear light treatments, its own fascias and body detailing, sport-oriented suspension and steering, and that futuristic interior. Banks of driver-facing controls sat around the instrument cluster, and a large collection of remote audio buttons crowded the steering wheel hub.
The Driver Information Center had trip computer functions, and the turbo version came with its own boost gauge. And while the head-up display was an option rather than standard equipment, the entire package certainly represented an ambitious proposition.
Some analysts started to compare this STE with European competitors, and as much as anything else, due to its price. After all, Pontiac was asking $23,775 for the Turbo STE at a time when the BMW 325i sedan started at $25,450. But the interior of the Pontiac was indeed very different from that of the BMW. After all, the contemporary BMW 3 Series was known more for its conventional driver-focused control layout, while Pontiac focused on displays, switches, information, and more visible technology as part of its pitch.
But the real question was whether Pontiac’s engineers could match all that futuristic hardware with an equally ambitious engine – and to get there, they called in some unlikely help.
ASC And McLaren Helped Turn 3.1 Liters Into 205 hp
1989-1990 Pontiac ASC McLaren Grand Prix LG5 3.1L Turbo V6 EngineBring A Trailer
While the interior and those electronics certainly became part of the STE Turbo’s headline appeal, its powertrain was arguably the more unusual piece of engineering. Typically, a regular 1990 Grand Prix STE would use GM’s naturally aspirated 3.1-liter V6, rated at 135 horsepower, and paired with either a five-speed manual or a four-speed automatic.
The Turbo, however, was something very different indeed. Here, Pontiac reached out to McLaren Engines to work on the turbocharged version of GM’s 60-degree V6, and ASC handled the final assembly work on the special Grand Prix models. ASC was also the manufacturer of the turbo system, while the result of those combined efforts was an intercooled 3.1-liter V6 producing 205 hp at 4,800 rpm and 220 lb-ft of torque at 3,200 rpm.
This revised car offered 70 hp more than the base Grand Prix STE, but that jump was achieved by doing far more than just attaching a turbo and hoping for the best. Instead, Pontiac introduced a different crankshaft, a higher-capacity oil pump, unique injectors, an engine oil cooler, and heavy-duty cooling hardware, with factory boost pressure set at 7.5 psi. The Turbo had a dedicated four-speed performance automatic rather than a manual transmission, and Pontiac also added four-wheel disc brakes with ABS as standard.
Pontiac claimed that this car could reach 60 mph in 8.0 seconds, set by a professional driver at a GM closed test facility. That may not sound too remarkable today, although it was still genuine performance for a family-sized Pontiac sedan back then. On paper, the Turbo STE looked like a bargain – more power, more technology, thousands less than a BMW. So why was Pontiac about to pull the plug?
The Turbo STE Had More Power Than The 325i But That Wasn’t The Whole Story
1991 BMW 325i finished in silver with tan interiorCars & Bids
There’s no doubt that at $23,775, the Turbo STE was an expensive Pontiac, and there was very little difference between its cost and that of a 1990 four-door BMW 325i. However, the latter car’s 2.5-liter inline six “only” made 168 hp and 164 lb-ft, so the Pontiac did enjoy a substantial headline power advantage.
That said, the 325i had a lot going for it in other areas. For example, it was rear-wheel drive and significantly lighter, coming in at around 2,855 lbs, whereas the Grand Prix weighed somewhere between 3,250 and 3,491 lbs, depending on its equipment. This meant that the BMW was more of a traditional sports sedan, with a lower mass, rear-wheel drive, a naturally aspirated straight-six engine, and an available manual transmission.
By contrast, Pontiac offered front-wheel drive, turbocharged torque, and an automatic transmission, as well as a heavily equipped interior and electronics that were almost too futuristic for their own good. And Pontiac was also facing some quite stiff competition much closer to home, too.
For example, the Ford 1990 Taurus SHO cost $21,633 and had a Yamaha-developed 3.0-liter DOHC V6, producing 220 hp. It came with its own five-speed manual and represented a different kind of American performance sedan, offering more horsepower for more than $2,000 less than the Pontiac.
Rarity Hasn’t Automatically Turned The STE Turbo Into A Fortune
1990 Pontiac Grand Prix STE Sedan interior frontBring a Trailer
Pontiac may have been trying to define a completely different kind of sports sedan with its STE Turbo, but it didn’t exactly give the car a lot of time to prove itself. The car only arrived sometime during the 1990 model year, and by the arrival of the 1991 Grand Prix range, the turbo sedan option was already gone. During that time, Pontiac didn’t sell a very large number of its STE Turbos either. One source suggests a combined production run of 5,773 for both STE and STE Turbo sedans, and another points to only around 1,000 of the actual turbocharged cars.
As rare as they appear to be, the market is certainly not viewing these cars as particularly collectible. For a start, it’s very hard to find evidence of genuine four-door STE turbos in the marketplace. While this Pontiac ought to have the ingredients for collectors to obsess over — with that short production run, unusual engineering, period styling, and unusual technological story — interest appears to be strangely absent.
1990 Pontiac Grand Prix STE Sedan sideBring a Trailer
The STE Turbo’s short life came down to the emergence of a brand-new engineering era for Pontiac. When the 1991 Grand Prix appeared, it came with a shiny new 3.4-liter with a twin-DOHC LQ1 V6. Pontiac decided that, rather than using boost to get as much output as possible from a conventional pushrod engine, it would embrace some very different technology involving dual overhead cams and four valves per cylinder.
With that high-revving naturally aspirated engine, Pontiac was now able to offer 210 hp from the 1991 Grand Prix fitted with a five-speed manual, or 200 hp if it had a four-speed automatic. The new engine, which produced 215 lb-ft of torque at 4,000 rpm, became standard in the GTP, and shoppers could order one on every other Grand Prix except the LE sedan.
On paper, the difference in power between the outgoing car and the incoming version wasn’t exactly revolutionary. The automatic LQ1 actually surrendered five advertised hp to the departing turbo engine, while the manual version gained only five. GM nevertheless felt that this change represented a far more sophisticated way to extract meaningful performance from its engines.
While all of that was going on, Pontiac continued with its futuristic electronics aspirations, with the Grand Prix STE itself lasting through 1993. But the particular STE Turbo version that also had 205 turbocharged horses to its name barely survived long enough to establish itself.
Sources: Bring A Trailer, BMW, Pontiac.
