Porsche's GT department is changing its tune. Where it previously abandoned the purist-favorite manual transmission for a quicker-shifting PDK, it's now embracing the old school once again.
The GT department, led by Andreas Preuninger, isn't giving up on customers who chase tenths of a second on track, but it's putting in huge effort into winning back the hearts of purists. The manual transmission is back in the GT3, and it signals a big shift at the company.
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"We are taking a lot of care about the driving emotion," said Preuninger, in an interview with Road & Track. "Not so much stubbornly, seriously, German-ly chasing lap time, lap time, lap time," he said with a mock stern voice. "At least, that's not my intention anymore."
This is a philosophy that was born from the critically acclaimed–and commercially successful–manual-equipped Cayman GT4 and the 911 R. These two helped Preuninger realize that there are customers for old-school purist cars.
What isn't new for Porsche, though, is the fact that this new GT3 represents a subtle, but noticeable evolution over the car it replaces. The biggest change is the engine, which doesn't seem all that different on paper, but is actually a significant update over the previous GT3's motor.
The engine is an evolution of the 4.0-liter naturally aspirated flat-six used in the 911 GT3 RS, which itself is a stroked version of the last GT3's motor. This new motor is actually largely similar to those used in current 911 race cars, including the brand-new RSR.
It makes 500 hp and 339 lb-ft of torque with a redline of 9000 rpm, which is the same for manual- and PDK-equipped cars. One of the biggest changes is a new, rigid valvetrain that doesn't use hydraulic lifters that's simpler than before, and interestingly, is less stiff than a conventional unit. This lack of stiffness means there's less resistance to turn the camshaft, which Preuninger says frees up eight horsepower.
Since there are no hydraulic actuators, the valves only need to be adjusted once, when the engine is built. Otherwise they're good for life. This valvetrain also requires less oil pressure and oil volume to run. Preuninger says the previous GT3's 3.8-liter unit requires 120 liters of oil circulating per minute. This new motor only requires 70 liters per minute, meaning there's more power to go to the tires.
For this motor, Preuninger and his team also developed a new intake system, a new oil pump, motorsports-inspired piston rings–made out of what Preuninger calls "Star Trek material"–and coated cylinder sleeves. All of this was done to improve throttle response, low- and mid-range torque and reduce inertia
"This engine for me, hands down, is maybe the best Porsche street engine ever made," said Preuninger.
Even counting the Carrera GT?
"That would be a close second" Preuninger says with a smile. "The immediacy of this engine is absolutely mind-boggling. From 2000 rpm all the way up to 9000 rpm, it's just a brute."
This engine is hooked up to a choice of two different transmissions–a seven-speed PDK that comes with an electronic differential, and a six-speed manual with a mechanical differential. The manual is an evolution of the new six-speed Preuninger and co. developed for the 911 R, but it doesn't share a part number. For the GT3, Porsche changed the flywheel and there's no option to get a single-mass flywheel, as on the R.
The chassis changes for the new GT3 are fairly subtle, but they carry a lot of influence from the 911 R.
"This exercise with the 911 R was such a welcome distraction from all our lap-time hunting," said Preuninger. "We found out that if you focus on the agility–making the car fun in tight turns, fun on canyons–we transferred something of that knowledge into the new GT3 as well."
Porsche also put a big emphasis on improving the aerodynamics of the GT3, and judging by the numbers, they've achieved an impressive result. Downforce is increased by 20 percent, but the drag coefficient remains the same as the previous GT3.
Much of the increase in downforce comes from a new rear diffuser inspired by–what else?–the one on the 911 R, with additional underbody vanes to channel air to the rear of the car. The rear wing also sits 20 millimeters higher than before, which allows it to be run at a lower angle of attack, helping reduce drag.
In our interview, Preuninger was very quick to emphasize that he really, really isn't all about chasing lap times any more. This new GT3 is still a track car, especially with PDK, but it's inching close to the 911 R. In other words, if you didn't get one of the 991 911 Rs built, this GT3 might be your best option.
And of course, Preuninger isn't about to forget the track rats either. There's a new GT3 RS on its way and, yes, it'll be PDK only.