Jan 4, 2008 11:07:26 AM
- Boxster Coupe GTS
- Rennteam Master
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- Loc: UK , United Kingdom
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- Registered on: Feb 23, 2005
997 GT2 first-drive by Exce11ence...
997 GT2 first-drive by Exce11ence...
"New Horizon"
For many years, upping the performance ante on the 911s rear-engined architecture has, in so many ways, defined Porsche and the enthusiasm surrounding it. So can the new 997 GT2, essentially a road-going track star on street-legal race rubber, make a strong case for the title of Best Yet? I hadn't given it much thought until the phone rang and Editor Stout offered to twist my arm with 530 horsepower. He had me at GT, but then he said something about Launch Assistant and six pounds per horsepower. Before Stout and I hung up, my bag was already packed for Germany.
From its inception as a 993-based car, the GT2 has held court as the ultimate turbocharged version of the 911. Porsche knows there's a place for a rear-drive 911 Turbo that lifts a little DNA from the glory days of endurance-racing 934s and 935s with big power and that familiar shape. Hot on the heels of the oft-underrated 996 GT2, the 997 GT2 makes a compelling argument that it deserves to be crowned the ultimate 911. It may even convince a few, Walter Röhrl included, that it's the ultimate Porsche. Sceptics may say, Come on, the exotic Carrera GT is mid-engined, with a V10 a road-going Le Mans racer with more horsepower and less weight.
That may be true, but the new GT2 with two-time world rally champion and Porsche test ace Walter Röhrl behind its wheel has lapped the Nürburgring's Nordschleife loop in an astounding 7 minutes, 32 seconds. Not only is that time a few ticks faster than his time in a Carrera GT, its 14 seconds faster than the previous 996-based GT2 and some 10 seconds faster than the current GT3 RS. How can that be, you ask? Well, the 997 GT2 offers more torque than any previous or current production Porsche sports car and the rear-end grip to put it to work.
Even without unpacking the GT2s serious torque advantage, it's obvious that the 997 GT2 is a serious tool. Giant air scoops envelop the front corners. The standard Turbo's foglights are gone. And a longer spoiler reaches for the ground. On the forward edge of the trunk-lid, a grill expels air on the topside of the nose after it has passed through the central front radiator, adding down force over the front axle. Special GT2 wheels look similar to those on the GT3, but they have wider spoke spacing for improved brake cooling. They offer a fairly unobstructed view of the new GT2s standard Porsche Ceramic Composite Brake setup, with its cross-drilled and vented 14.96-inch front and 13.78-inch rear rotors grabbed by six-piston front and four-piston rear callipers.
As a result, the thin-spoked wheels seem almost too delicate for such a serious speed weapon. They're wrapped in 235/35ZR19 front and 325/30ZR19 rear tires designed specifically for this model. The GT2s aggressive, bi-plane rear wing features scoops which feed intakes below the deck-lid. Weissach spent a lot of time on this wing, its engineers planning for a replaceable rear splitter on the upper element to vary down force. Extensive work in the wind tunnel proved that a changeable wicker added no down force or measurable gain to the aero package.
Form follows function all the way to the lower edge of the rear bumper, where slotted gills extract air through the intercoolers. Overall, the package reduced the coefficient of drag from 0.34 on the previous GT2 down to down to 0.32 on the 997. That's a figure that would combine nicely with targeted power numbers to make the 997 GT2 Porsches first 200+mph 911.
When the business case was first made for the GT2, we targeted 520 to 530 horsepower, says GT2 project manager Alan Lewin. But we didn't have a particular area of engine development in mind to raise that figure. The engine is largely similar to the standard 3.6-litre unit in the 997 Turbo, a dry-sump, water-cooled, twin-turbocharged flat six with nine separate oil pumps and variable camshaft geometry. Reveals Lewin: We looked into larger turbochargers, but that always comes with the penalty of turbo lag.
While Porsche did massage the Turbo's Variable Turbine Geometry turbochargers with new turbine wheels, compressors, and housings, it says those changes were mere nuances aimed at improving flow. The majority of the GT2s 50-horse gain over the Turbo comes thanks to a new intake manifold that looks counter-intuitive at first glance, thanks to its short intake runners. When stuffing as much air as possible into the combustion chamber, you're usually working with a resonance inside the area between the throttle body and head created by the valves opening and closing. Air expands and contracts, so, to shove it in faster, you typically try to push it harder during the compression phase to move more air into the chamber. The by product of compressing this air is heat, and a loss of thermal efficiency in the heated air/fuel mixture.
Porsches GT2 engine team knew that, during the expansion phase of the resonance inside the manifold, the air/fuel mixture was cooling. By capitalizing on that phase of the valve resonance and amplifying the expansion of the intake air as it travels from the throttle body towards the cylinder, the new manifold uses a longer distributor area and shorter intake runners to keep mixture temperatures down. The lower pressure is offset by additional boost. This keeps the charge about 20* F cooler, which yields quicker ignition in the combustion chamber, less sensitivity with regards to detonation, more horsepower, and a lower fuel-consumption rate under full load. The combination allows for 1.4 bars of boost and a solid 501 lb-ft of torque from 2200 to 4500rpm.
All of this talk of horsepower and torque has us itching to drive the car, but then there's the weather in northern Germany: wet. Not so excellent for exploring the dynamics of the fastest production 911 ever made - especially since its rear-drive only. It's rainy enough that the Porsche team decided to alter their plans and lead us by Cayenne like baby ducks directly to the track, which we were scheduled to visit at the end of a full days drive. Driving past barracks and mysterious grass-covered bunkers, some of the press corps is questioning what sort of track is on tap. As it turns out, it's a former Luftwaffe airfield northwest of our home base in the small town of Dinklage.
Walter Röhrl is already circulating the impromptu airport course, streaking down the main runway with a plume of spray behind his GT2 like a full-blown land-speed record attempt on a dusty salt flat. As the car streaks across the horizon, even more impressive than the sight is the sound of the 911 litreally tearing and compressing the air around it in a shriek louder than the measured wail flowing from the exhaust pipes. Röhrl comes around closer on a short straight, tail out at 30* in a perfect drift. Watching from outside, Röhrl is obviously starting the lap with Stability Control and Traction Control on, as the motor spools up with little hiccups of interruption as the car leaps forward from a particularly wet 90* corner. Later in the lap, the slip angles increase and the smooth howl of the turbocharged six reveals he has disabled the systems.
Riding with Röhrl is a treat, amplified by the iffy weather. Its one of those situations where you wallow in awe for a few seconds, then shift gears and observe his ballet-smooth technique and start asking questions because its not like he's going to get distracted and put a wheel wrong. Where it's merely wet and not puddled, the GT2 turns in like its dry. Its one of Röhrl's favourite attributes of the car, and he says it turns into corners better than the GT3 RS. Through puddles with Stability Control on, it sounds like early 1990s F1 traction control is at work, with the car cutting out but still leaping forward.
It's the first use of Stability Control on a 911 GT model. And, on a mixed wet and drying surface combined with the turbo 3.6s explosive power delivery, it makes sense. The yaw parameters activating the Stability Control functions are higher than those for any other 911s PSM system from which it is derived, allowing the GT2 to rotate further before intervention. To demonstrate, Röhrl starts out with the Porsche Active Suspension Management (PASM) shocks set to Normal with SC and TC on. The GT2 limits the slip angle of his slides and keeps us accelerating across puddles on the slick roadway.
It seems pretty stable‚ I remark as we hurtle down the straight. Röhrl replies by simply taking both hands off the wheel as we pass 250 km/h (155 mph). Just before he touches the brakes, we cross 300 km/h (186 mph) in the wet. Seconds later, the callipers grab the composite rotors and point the nose to the ground, scrubbing off over 100 mph effortlessly. Nice. After reaching down and disabling SC and TC, Röhrl says, Even with it off, the car is very stable and easy to catch.
Perfectly smooth drifts are no big deal for Röhrl, and in the middle of one I ask him why he was faster at the Nürburgring in the 997 GT2 than the mid-engined Carrera GT. Says Röhrl: Ah yes, its actually easier to drive. The GT has a long wheelbase and the mid-engine. It is stable, but it takes longer to gather up in a slide. So the GT2 breaks away maybe faster, but is also saved faster, and I'm on the gas sooner. He also mentioned his fastest time was set with PASM on the Normal setting with SC and TC off.
Suspension chief Karsten Schebstad explains that the setup between PASM Normal and Sport aren't just stair steps of stiffness. For most situations, the Normal setting produces the best results, as the GT2 PASM is more aggressive than the standard Turbo's and the Nordschleife is far too bumpy for the Sport setting which is meant for billiard-smooth tracks. However, the shock stiffness of the package of each setting can overlap depending upon conditions. In other words, there may be situations such as extremely high speeds where Normal would stiffen the valving to levels within the range of Sport while Sport settings may dip into the upper reaches of the Normal valving.
As for the PSM-like Stability Control system, the GT2 marks the first time Porsche is allowing the driver to disable the electronic safety net in stages, turning off SC while leaving Traction Control on to aid in power delivery. A separate button disables SC and TC, which allows the driver to control the GT2 without assistance. Unlike the PSM systems in other Porsches, once it's off, it can only be reactivated via the button or restarting the car. All other versions of PSM can turn themselves back on to intervene should the computer determine that the end is near.
That's not to say there aren't a couple of tricks built into SC, however. Two functions can't be deactivated Anti-lock Braking and Corner Brake Control. The latter was developed for the track and Röhrl demonstrates it at the end of our laps. Says Röhrl: Say you've come into this corner too fast, you're trail-braking hard and turning at the same time. He brakes and turns hard. Too hard. With all the weight on the front of the car, the rear begins to come around. Just after it breaks loose, the front end suddenly turns in harder and rotation stops as individual brakes help arrest the rotation. Had the front not been so loaded, CBC wouldn't have intervened. Thus, power-on drifts with an electronic safety net are possible. Clever...
997-GT2_Exce11ence-article-link
"New Horizon"
For many years, upping the performance ante on the 911s rear-engined architecture has, in so many ways, defined Porsche and the enthusiasm surrounding it. So can the new 997 GT2, essentially a road-going track star on street-legal race rubber, make a strong case for the title of Best Yet? I hadn't given it much thought until the phone rang and Editor Stout offered to twist my arm with 530 horsepower. He had me at GT, but then he said something about Launch Assistant and six pounds per horsepower. Before Stout and I hung up, my bag was already packed for Germany.
From its inception as a 993-based car, the GT2 has held court as the ultimate turbocharged version of the 911. Porsche knows there's a place for a rear-drive 911 Turbo that lifts a little DNA from the glory days of endurance-racing 934s and 935s with big power and that familiar shape. Hot on the heels of the oft-underrated 996 GT2, the 997 GT2 makes a compelling argument that it deserves to be crowned the ultimate 911. It may even convince a few, Walter Röhrl included, that it's the ultimate Porsche. Sceptics may say, Come on, the exotic Carrera GT is mid-engined, with a V10 a road-going Le Mans racer with more horsepower and less weight.
That may be true, but the new GT2 with two-time world rally champion and Porsche test ace Walter Röhrl behind its wheel has lapped the Nürburgring's Nordschleife loop in an astounding 7 minutes, 32 seconds. Not only is that time a few ticks faster than his time in a Carrera GT, its 14 seconds faster than the previous 996-based GT2 and some 10 seconds faster than the current GT3 RS. How can that be, you ask? Well, the 997 GT2 offers more torque than any previous or current production Porsche sports car and the rear-end grip to put it to work.
Even without unpacking the GT2s serious torque advantage, it's obvious that the 997 GT2 is a serious tool. Giant air scoops envelop the front corners. The standard Turbo's foglights are gone. And a longer spoiler reaches for the ground. On the forward edge of the trunk-lid, a grill expels air on the topside of the nose after it has passed through the central front radiator, adding down force over the front axle. Special GT2 wheels look similar to those on the GT3, but they have wider spoke spacing for improved brake cooling. They offer a fairly unobstructed view of the new GT2s standard Porsche Ceramic Composite Brake setup, with its cross-drilled and vented 14.96-inch front and 13.78-inch rear rotors grabbed by six-piston front and four-piston rear callipers.
As a result, the thin-spoked wheels seem almost too delicate for such a serious speed weapon. They're wrapped in 235/35ZR19 front and 325/30ZR19 rear tires designed specifically for this model. The GT2s aggressive, bi-plane rear wing features scoops which feed intakes below the deck-lid. Weissach spent a lot of time on this wing, its engineers planning for a replaceable rear splitter on the upper element to vary down force. Extensive work in the wind tunnel proved that a changeable wicker added no down force or measurable gain to the aero package.
Form follows function all the way to the lower edge of the rear bumper, where slotted gills extract air through the intercoolers. Overall, the package reduced the coefficient of drag from 0.34 on the previous GT2 down to down to 0.32 on the 997. That's a figure that would combine nicely with targeted power numbers to make the 997 GT2 Porsches first 200+mph 911.
When the business case was first made for the GT2, we targeted 520 to 530 horsepower, says GT2 project manager Alan Lewin. But we didn't have a particular area of engine development in mind to raise that figure. The engine is largely similar to the standard 3.6-litre unit in the 997 Turbo, a dry-sump, water-cooled, twin-turbocharged flat six with nine separate oil pumps and variable camshaft geometry. Reveals Lewin: We looked into larger turbochargers, but that always comes with the penalty of turbo lag.
While Porsche did massage the Turbo's Variable Turbine Geometry turbochargers with new turbine wheels, compressors, and housings, it says those changes were mere nuances aimed at improving flow. The majority of the GT2s 50-horse gain over the Turbo comes thanks to a new intake manifold that looks counter-intuitive at first glance, thanks to its short intake runners. When stuffing as much air as possible into the combustion chamber, you're usually working with a resonance inside the area between the throttle body and head created by the valves opening and closing. Air expands and contracts, so, to shove it in faster, you typically try to push it harder during the compression phase to move more air into the chamber. The by product of compressing this air is heat, and a loss of thermal efficiency in the heated air/fuel mixture.
Porsches GT2 engine team knew that, during the expansion phase of the resonance inside the manifold, the air/fuel mixture was cooling. By capitalizing on that phase of the valve resonance and amplifying the expansion of the intake air as it travels from the throttle body towards the cylinder, the new manifold uses a longer distributor area and shorter intake runners to keep mixture temperatures down. The lower pressure is offset by additional boost. This keeps the charge about 20* F cooler, which yields quicker ignition in the combustion chamber, less sensitivity with regards to detonation, more horsepower, and a lower fuel-consumption rate under full load. The combination allows for 1.4 bars of boost and a solid 501 lb-ft of torque from 2200 to 4500rpm.
All of this talk of horsepower and torque has us itching to drive the car, but then there's the weather in northern Germany: wet. Not so excellent for exploring the dynamics of the fastest production 911 ever made - especially since its rear-drive only. It's rainy enough that the Porsche team decided to alter their plans and lead us by Cayenne like baby ducks directly to the track, which we were scheduled to visit at the end of a full days drive. Driving past barracks and mysterious grass-covered bunkers, some of the press corps is questioning what sort of track is on tap. As it turns out, it's a former Luftwaffe airfield northwest of our home base in the small town of Dinklage.
Walter Röhrl is already circulating the impromptu airport course, streaking down the main runway with a plume of spray behind his GT2 like a full-blown land-speed record attempt on a dusty salt flat. As the car streaks across the horizon, even more impressive than the sight is the sound of the 911 litreally tearing and compressing the air around it in a shriek louder than the measured wail flowing from the exhaust pipes. Röhrl comes around closer on a short straight, tail out at 30* in a perfect drift. Watching from outside, Röhrl is obviously starting the lap with Stability Control and Traction Control on, as the motor spools up with little hiccups of interruption as the car leaps forward from a particularly wet 90* corner. Later in the lap, the slip angles increase and the smooth howl of the turbocharged six reveals he has disabled the systems.
Riding with Röhrl is a treat, amplified by the iffy weather. Its one of those situations where you wallow in awe for a few seconds, then shift gears and observe his ballet-smooth technique and start asking questions because its not like he's going to get distracted and put a wheel wrong. Where it's merely wet and not puddled, the GT2 turns in like its dry. Its one of Röhrl's favourite attributes of the car, and he says it turns into corners better than the GT3 RS. Through puddles with Stability Control on, it sounds like early 1990s F1 traction control is at work, with the car cutting out but still leaping forward.
It's the first use of Stability Control on a 911 GT model. And, on a mixed wet and drying surface combined with the turbo 3.6s explosive power delivery, it makes sense. The yaw parameters activating the Stability Control functions are higher than those for any other 911s PSM system from which it is derived, allowing the GT2 to rotate further before intervention. To demonstrate, Röhrl starts out with the Porsche Active Suspension Management (PASM) shocks set to Normal with SC and TC on. The GT2 limits the slip angle of his slides and keeps us accelerating across puddles on the slick roadway.
It seems pretty stable‚ I remark as we hurtle down the straight. Röhrl replies by simply taking both hands off the wheel as we pass 250 km/h (155 mph). Just before he touches the brakes, we cross 300 km/h (186 mph) in the wet. Seconds later, the callipers grab the composite rotors and point the nose to the ground, scrubbing off over 100 mph effortlessly. Nice. After reaching down and disabling SC and TC, Röhrl says, Even with it off, the car is very stable and easy to catch.
Perfectly smooth drifts are no big deal for Röhrl, and in the middle of one I ask him why he was faster at the Nürburgring in the 997 GT2 than the mid-engined Carrera GT. Says Röhrl: Ah yes, its actually easier to drive. The GT has a long wheelbase and the mid-engine. It is stable, but it takes longer to gather up in a slide. So the GT2 breaks away maybe faster, but is also saved faster, and I'm on the gas sooner. He also mentioned his fastest time was set with PASM on the Normal setting with SC and TC off.
Suspension chief Karsten Schebstad explains that the setup between PASM Normal and Sport aren't just stair steps of stiffness. For most situations, the Normal setting produces the best results, as the GT2 PASM is more aggressive than the standard Turbo's and the Nordschleife is far too bumpy for the Sport setting which is meant for billiard-smooth tracks. However, the shock stiffness of the package of each setting can overlap depending upon conditions. In other words, there may be situations such as extremely high speeds where Normal would stiffen the valving to levels within the range of Sport while Sport settings may dip into the upper reaches of the Normal valving.
As for the PSM-like Stability Control system, the GT2 marks the first time Porsche is allowing the driver to disable the electronic safety net in stages, turning off SC while leaving Traction Control on to aid in power delivery. A separate button disables SC and TC, which allows the driver to control the GT2 without assistance. Unlike the PSM systems in other Porsches, once it's off, it can only be reactivated via the button or restarting the car. All other versions of PSM can turn themselves back on to intervene should the computer determine that the end is near.
That's not to say there aren't a couple of tricks built into SC, however. Two functions can't be deactivated Anti-lock Braking and Corner Brake Control. The latter was developed for the track and Röhrl demonstrates it at the end of our laps. Says Röhrl: Say you've come into this corner too fast, you're trail-braking hard and turning at the same time. He brakes and turns hard. Too hard. With all the weight on the front of the car, the rear begins to come around. Just after it breaks loose, the front end suddenly turns in harder and rotation stops as individual brakes help arrest the rotation. Had the front not been so loaded, CBC wouldn't have intervened. Thus, power-on drifts with an electronic safety net are possible. Clever...
997-GT2_Exce11ence-article-link
