2001 Porsche 911

Was that really me driving?
"Go ahead. Try it." My driving instructor was eager to send me down the slalom in the 1999 Porsche 911 Carrera 4.

Intrigued, I punched the gas pedal and started dodging orange cones set out on the pavement. A few seconds later, I had swished around them all, amazed at the stability and grip of this new Porsche. Second, third and fourth runs in the slalom confirmed this was no aberration. The car behaved impeccably. As I'd start to swing wide, there seemed to be a quick, sudden tire grip at just the right corner, helping to get me in the right direction.

What was that? I wondered. It was all PSM. No, not PMS; P-S-M. PSM is Porsche Stability Management system, and the 1999 4-wheel-drive 911 Carrera is the first Porsche to get it.

Much like stability systems on some luxury cars, PSM's computer constantly monitors the Carrera 4's motions, direction and what the driver is doing with the steering wheel and throttle. The system uses the anti-lock brakes, then engine timing and throttle, if necessary, to try to get the car back in line.

Yet, PSM works so subtly on the Carrera 4—and waits a bit to kick in—that drivers still can enjoy the thrills and exhilaration of a Porsche. That subtleness is the difference between Porsche's PSM and stability management systems on other cars, Porsche officials maintained.

Even while using the same supplier for PSM components as Mercedes-Benz and other manufacturers, Porsche made sure its stability system doesn't activate too early and rob drivers of their Porsche thrills. "We designed it so the car still can be driven like a Porsche," said Thomas Herold, project manager for the Carrera 4 at Porsche AG in Germany.

But the decision wasn't easy. "PSM was, for us, a real big step," Herold said. "There had been lots of discussion in the company if this was a system for a sports car." And the careful tuning of PSM took a long time, he said.

Still, in perhaps a compromise for diehard Porsche fans, there is a button on the dashboard of the 911 Carrera 4 that will turn PSM off. Then, you best prepare to work a lot harder to look like an expert driver. The difference in behavior was obvious when I hit the skid pad. With PSM turned off, I spun the test car nearly 360 degrees. With PSM on, I couldn't get it to repeat that spin no matter how hard I tried. In an autocross, it was the same thing. With PSM on, I swept through the course with a comfort and ease that was impossible, at least for a layperson like myself, all on my own.

Think safety
Now you may be thinking the Porsche 911 Carrera 4 is only good on slaloms, skidpads and autocross courses. Think again. It's also good on everyday roads. Herold pointed out the system can help a driver control the car and avoid a bad spin if a tire were to blow, for example. It can also help a driver maintain control if he or she has to duck around a sudden obstacle on the road.

And, he said, a driver might feel a bit more relaxed while traveling with PSM on board, and that sense of calm could help a driver's reaction in an emergency situation. "You can react better because not all your muscles are cramped," Herold said.

Indeed, Bob Carlson, general manager of public relations at Porsche Cars North America Inc., noted that PSM, the Carrera 4's standard 4-wheel-drive system, and standard frontal and side airbags all help make this "the best handling and safest 911 ever built."

One important note, though: PSM won't defy the laws of physics, so you can't go driving irresponsibly and expect PSM to rescue you.

Other new features
The Carrera 4 is also the first Porsche with an electronic gas pedal, known as E-gas. In this setup, a sensor at the pedal sends a signal to a computer, and the computer tells the throttle what the driver is requesting. E-gas helps reduce emissions and improves fuel economy, Herold explained.

And, for the first time, buyers of 4-wheel-drive Carreras can choose a 5-speed automatic transmission. It's Porsche's Tiptronic S system that lets drivers decide if they want to shift manually, without a clutch pedal, from gear to gear. The shift buttons are on the steering wheel. A 6-speed manual is also offered.

Powered by all four wheels
Of course, you can't talk about the Carrera 4 without noting the permanent 4-wheel-drive system. In normal driving, about five percent of the power is sent to the front wheels. This, combined with the positioning of the 3.4-liter 296-horsepower six cylinder at the rear, makes for Porsche's rear-dominant handling characteristics.

But if a rear wheel slips, up to 40 percent of the power can be transferred automatically to the front wheels, helping give this sports car better traction than most. Porsche uses a viscous clutch to control the power transfer from rear to front. In the 1999 Carrera 4, the viscous clutch is moved from the transmission and is now integrated into the front differential casing. Porsche noted this relocation improves the weight distribution of the car—an important attribute for a sports car.

Same updated styling
Externally, there's not much to differentiate the 4-wheel-drive Carrera from 2-wheel-drive 911s. It gets special, 17-inch standard tires, distinctive-looking, gray brake calipers and different badging. Inside, it benefits from the same, smart, interior ergonomics as the 2-wheel-drive 911s.

The two front seats feel roomier than in previous 911s', and the instrument gauges have a modern, Porsche Boxster-style arrangement. Glossy black buttons set off the sporty feel of this car, which is wrapped in Porsche's familiar, sleek, sports-car body.

But the inside is still small, and while there are two seat-like spots in the rear, they're really more like holding places for briefcases, bags and other stuff. Compared to the already cramped trunk of the 2-wheel-drive models, the C4's trunk also suffers a bit, losing about 1.5 cubic feet due to extra 4-wheel-drive mechanicals.

The Carrera 4 comes in two body styles—coupe and cabriolet. Thankfully, PSM is standard in both.