Road Test
It had to happen eventually. An automatic transmission has finally found its way into that most macho of cars, the Porsche 911 Turbo. And we're not talking one of the fancy computer-controlled manual gearboxes used on the Grand Prix circuit. The Turbo on these pages pumps its 415 horsepower through a torque-converter-fed, planetary-gear-modulated slushbox, fundamentally like the one found in any Ford or Chevy.
Just put it in "D" and off you go -- as fast as you dare. We clocked the Turbo automatic to 60 mph in 4.2 seconds and through the quarter mile in 12.6 seconds at 112 mph. That's only 0.3 second slower than the manual 911 Turbo we tested last September, although the gap does increase at higher speeds. Getting to 150 mph, for example, took 25.9 seconds, 4.3 seconds slower than the number we accomplished shifting manually. Still, this is the quickest automatic-shifting car we've ever tested -- even quicker than the Ferrari 360 Modena with its fancy F1-style, computer-controlled gearbox.
When you plant your left foot on the brake and bring up the boost with your right before launching, the Turbo automatic readily produces the rocketlike acceleration figures noted above. But the car feels benign and not all that eager when pulling away from a red light in downtown traffic. That's because the five-speed gearbox normally starts in second gear, unless you either floor the throttle or use the steering-wheel-mounted shift rockers to select first gear. In second gear, before boost has had a chance to build in the 3.6-liter engine, the 3597-pound Turbo's acceleration does not inspire awe.
Keep your foot in it, however, and the pace quickly picks up, although there's never the explosion pounding your backside that was produced by the original 1976 Turbo model. Of course, that car had a 3.0-liter engine with a piddling 6.5:1 compression ratio. It was quite gutless until its single large turbo spooled up.
With twin turbos and intercoolers, variable valve timing and lift, and a lofty 9.4:1 compression ratio, this turbo engine transitions to boost smoothly and quickly. Still, there's a little lag, and to eliminate it completely, it's best to keep the tachometer needle above 3000 rpm.
That's where the automatic transmission, dubbed Tiptronic S and raising the price of the base Turbo by $3973 to $121,590, comes in. Slap the floor shifter sideways from the D position into the M slot, and you can play either rocker switch on the steering-wheel spokes to move up or down within the five available gears. These manually instigated shifts are quick and solid, limited only by the transmission's refusal to execute any commands that would jeopardize the driveline -- such as downshifting to second at 110 mph.
In fact, you can take over the shifting chores any time you wish without sliding the shift lever from D to M by simply flicking the rocker switches on the steering wheel. You realize full manual control, but the transmission reverts to the D program eight seconds after your last manual input.
Even if you never touch the rockers on the steering wheel, this transmission is always searching for ways to help you out. Slap the throttle to the floor for an instant, and the transmission will downshift one or two gears to set up a swift pass. Lift off the throttle suddenly, and the transmission will delay the upshift, assuming that you are braking for a corner and want to stay in the lower gear. Recognizing when you are in a hard corner, the transmission will avoid shifting if possible. In fact, this gearbox has so many tricks to help you out that a weekend behind the wheel is not nearly long enough to identify all of them.
