Unveiled to the world in 1999, the Porsche 911 GT3 was a high performance variant of the original water-cooled version of the Porsche 911, the 996. It continued the 25 year tradition of low-weight RS models that was ended with the 993 RS. The name GT3 was taken from the Fiat GT class that it had been designed for, and it didn't use the simple engine of the standard production versions of the 996, while also a naturally-aspirated variation of the turbocharged Porsche 962 and Porsche 911 GT1 race vehicles. Though it didn't fit into GT racing regulations like the 993 GT2, the turbo-charged Porsche 911 GT2 was added to the maker's lineup. Racing versions of the GT3 were awarded several major 24h races and completely dominated their class at Le Mans.
The Porsche 911 GTI won the 24 Hours of Le Mans in 1998 and Porsche chose not to enter the '99 Le Mans due to not having a factory vehicle that was good enough to defend the overall win against the competition by major automakers. This was also due to an internal agreement again on less expensive GT racing classes at the Grand-Am Rolex racing series, the 24 Hours of Le Mans, and started plans to update the new 996 generation of the 911. At the same time they produced a road-worthy variant, they developed a race car. In 1999 this car was introduced at the Geneva Motor Show before it went on sale.
The GT3 came with an engine unlike any other 996 models, even though it shared the same basic 3.6 liter displacement of the standard 996 ‘integrated dry-sump' flat-six engine. This engine is based completely on the original air-cooled 911's versatile, true dry-sump crankcase with an external oil tank. Originally the GT3's engine had 360 PS, in comparison to the 300 PS of the original 996.
Quite similar to the completely water-cooled 962 racing car's engine, the GT3 engine configuration was a so called 'split' crankcase uses separate water jackets added onto each side of the crankcase to cool banks of three cylinders with water pumped through a radiator, rather than a fan and finned cylinders. This engine is also based on this same crankcase. This engine is different though because the 962 utilized 6 individual cylinder heads while the GT1/GT3 used 2 cylinder heads, each covering a bank of 3 cylinders. One could think of the GT3 engine as a similar to a 959 engine, but with water-cooled cylinders.
The basic casting utilized for the crankcase of the GT3, up until 2004, was virtually the same as the air-cooled engine. The '964' casting number on the bottom of the crankcase and areas could clearly be seen and were normally machined in the air-cooled application that are not machined for use in the water-cooled application. Halfway through the 2004 year, a '996' casting number crankcase to eliminate these external air-cooled remnants, while internally it remained virtually the same.
Dating back to the Porsche 904/6 of the mid-1960's, the engine gives the GT3 a distinct racing heritage all the way up the racing vehicles of today.
The GT3 utilized a manual gearbox that was also of air-cooled 911 heritage, due to the 911 air-cooled crankcase that used the Porsche 356 engine to transmission mounting flange configuration. The gear ratios were interchangeable on the gearbox and it was much more durable which makes it more preferable for racing over the standard 996 type 911 gearbox. The most ‘powerful naturally aspirated six-cylinder engine' in any production vehicle, was the 3.8 liter flat-six engine in the 997 GT3 and GT3 RS, rated at 435 hp.
The 2004 Porsche 911 GT3 is considered to be the most powerful non-turbocharged production vehicle that had ever been offered in North America. Considered to be a true sports vehicle that allowed you to achieve lap times on the racetrack, no one really expected it to also be a street-legal and non-turbocharged road vehicle. President and chief executive officer of Porsche Cars North America, Peter Scwarzenbauer is quoted as 'This is the fastest normally aspirated Porsche road car' and 'the sports car for the purist, through and through'.
Though the GT3 didn't come with a back seat, and other commodities drivers really preferred, it continued to be a car than can be driven on a daily basis. The GT3 also maintains the same fuel consumption ratios as other 911 models, though it produced more horsepower and torque. The '04 Porsche 911 GT3 is rated at 380 hp at 7,400 rpm and 284 lb-ft of torque at 5,000 rpm. In first, second, third and fourth gears, the engine revs to 8,200 rpm right before its computerized rev limiter is activated.
The 04 Porsche 911 GT3 could achieve 0-60mph in just 4.3 seconds and could hit 100 mph in just 9.4 seconds. The brakes were also bigger on the GT3 than the 911 Turbo's. The GT3 is also equipped with 13.78-inch front brake discs and six-piston fixed calipers that increase the contact area between the discs and the pads. In a carry-over of a Porsche tradition, the six-piston brake calipers are adorned with a red paint. By 40% these calipers enlarge the contact area between the brake lining and the brake disc in comparison to the first generation GT3. The front discs are also nearly an inch larger than those found on the '03 911 turbo. Much like the Turbo's, the rear discs are 13.00 inches. Patented by Porsche, the cooling ducts were inner-vented and cross drilled, while the front discs are 1.34 inches thick. The sickle-shaped ducts act like a turbine inside the discs which made a significant contribution to cooling behavior.
The rotors at the rear measure 1.10 inches thick and are cross-drilled and inner-vented and feature four-piston calipers. Brake caliper pistons are separated by heat-insulating circonium ceramic inserts which reduced the transmission of temperatures from the brakes to the hydraulic fluid. The Porsche 911 GT3 came with enhanced aerodynamics, mainly due the streamlining of the vehicle's body that included a swept-back nose, a large rear spoiler, and sculpted side sills. All of these components together reduce lift forces on both rear and front axles. The improved aerodynamics along with the more powerful engine resulted in a top track speed of 190 mph. The aerodynamic nature also provides more flow that cooled the GT3's braking system. Directing air to the brake discs and calipers were spoilers that were integrated into the cars wheel wells.
by Jessican Donaldson