The last of the air-cooled 911s.
The Type 993 was the last of the air-cooled 911s, and therefore the last air-cooled Porsche. This was another major redesign, which included some subtle changes to the shape of the car (although it was still based on the original design). Some parts carried over from the 964, but those that did were upgraded for the new generation. The engine was once again a 3.6-liter air-cooled flat-6, carried over from the 964. Here it produced 272 horsepower, and in 1995 got a boost up to 285hp.
The 4-speed Tiptronic automatic was once again offered, although this too was more refined. New software gave it the ability to distinguish between normal driving, hill climbs and descents. Starting with the 1995 model year, the Tiptronic S was offered, with steering wheel-mounted controls. The 993 also introduced the six-speed manual transmission as standard to the 911 range, this would remain the standard until Porsche introduced the world's first seven-speed manual in the Type 991 911 in 2011. Another significant change was the move to an all-alloy subframe, to which the new all-alloy multi-arm rear suspension attached.
This, along with the car's new wider stance, greatly helped with stability, and reduced the tendency toward oversteer when lifting off the throttle in a corner. This had previously been a major downside of the 911, and it invited comparisons to the infamous Chevy Corvair, of "Unsafe at Any Speed" fame. Such oversteer is unavoidable to a certain degree in rear-engine cars, simply because as the result of so much weight being behind the rear axle, but the 993's suspension setup was a massive improvement. The all-wheel-drive system on the 993 was also improved over the 964.
While the 964's system was designed with the lessons from the 959 in mind, it was the 993 which actually had the more similar system. This was one which was not only lighter but also less prone to understeer, a problem which the 964 suffered from right up until the oversteer kicked in. Although the 993 engine was largely the same as that of the 964 in naturally-aspirated form, significant changed where made to the Turbo engine prior to its debut in 1995. The heads were redesigned, as was the exhaust system; but more significant was the new twin-turbo system, which incorporated dual air-to-air intercoolers, housed in a large fixed rear wing.
This setup is also more closely related to the 959, as were the new hollow-spoke wheels for the Turbo. With the help of the twin KKK K16 turbochargers, the engine produced 408 horsepower in the standard Turbo and 425hp in the Turbo S. The 993 Turbo was also the first Turbo model to get AWD, something which has been standard ever since. The bodywork of the Turbo was made more distinct from that of the Carrera as well, and even though "Turbo look" Carrera models have existed through several generations, the difference between the standard Carrera and the Turbo is quite noticeable.
S versions of the Carrera, Carrera 4 and Turbo were al produced, but these represent a less-dramatic advantage over the standard models than the 964 Turbo S was. A Carrera RS was once again offered, and here it is more obviously the precursor to the GT3 models to come in later generations. This naturally-aspirated high-performance variant is recognizable by its fixed rear wing, one notably different from that of the Turbo models. There are also small front flaps and special 18-inch aluminum wheels. The difference between the RS and standard Carrera is most dramatic when it comes to the engine.
Though the engine of the RS is based on the standard car's power plant, here it displaces 3.8 liters, and produces 300 horsepower. A more track-focused version of the RS was also available, known as either the RSR or the RS Clubsport, depending on the market. And speaking of markets, no, you couldn't buy one in the US. The most significant version of the 993 was the GT2, a homologated race car based on the Turbo. It had essentially the same engine as the standard Turbo, but was tuned to produce 435 horsepower.
Towards the end of the 993 Turbo's production cycle, some versions of the GT2 were tuned to produce as much as 600 horsepower; but these were soon replaced by the GT1, a different homologated car which wore a 911 badge but had very little in common with any other 911. The GT2 came into being at a time when there was a significant backlash within racing governing bodies against AWD. It was perceived that the few cars which had been able to successfully implement it had an unfair advantage over other cars and it might seem odd for motorsports to discourage technological advancement.
Remember, however, that the FIA is French, and AWD was not a technology which French automakers were at the forefront of. Perhaps it was simply that AWD gave an advantage over French cars. In any case, the GT2 was designed to be RWD only, so that it would be allowed to compete. Though there was a disadvantage when it came to handling, this did mean that there was a certain amount of weight saving. Possibly the most fascinating part of the 933 is that such a modern and sophisticated car had an air-cooled engine. This was an all but unheard of system by the Nineties, and you have to hand it to Porsche for trying.