DR Review: 997.2 Carrera 4
http://www.drivers-republic.com/first_lo...85ce49cf6f6bbf6
Porsche spends a great deal of time and money developing the four-wheel drive version of its Carrera. Its brief is simple: in the dry it should mimic the behaviour of the standard Carrera and in the wet bring added security and traction.
But the simple brief has a not-so-simple solution, involving the electronically controlled PTM (Porsche Traction Management) system from the Turbo and a standard-fit rear limited-slip differential.
The control unit that determines how much power to distribute between front and rear axles is a work of genius - not only measuring wheel speeds and lateral forces but also taking account of the steering angle before shuffling the torque. The aim is to prevent under- or oversteer before they occur, but if the car is sliding and you're already applying corrective lock the C4 will work with your reactions to bring things under control more smoothly and more quickly. And all this in no more than 100-milliseconds.
Despite such technological brilliance it's a sad fact of life for Porsche's chassis and transmission engineers that many customers are almost certainly going to choose the C4 on looks alone. The old school reflector strip across the back split opinion (I love it, many didn't) - but the wide body from the Turbo and GT3RS is a universal hit, accentuating the 997's curves without looking OTT. If you love the look then the circa-Pounds4000 premium Porsche wants for the C4 over the C2 is money well spent. Whether its multi-plate clutch in the front axle, PTM system and rear limited-slip diff have a similarly transforming effect on the dynamics should be revealed on quiet roads near Berlin and a Michelin test facility located on an ex-Cold War Russian airbase nearby.
Unfortunately the road driving on offer is restricted to roads that are either straight and very smooth or so badly surfaced that driving quickly is out of the question. On the few sequences of corners we do find the C4 feels agile and grippy, with just a shade more understeer than you might find in the standard Carrera. The wider rear track and huge 295-section (305-section for the C4S) tyres give the rear axle enormous grip so its no surprise that the front pushes wide first when you start dipping into the 3.6-litre, 340bhp (345PS) flat-six. I should mention that the new direct-injection unit feels strong and punchy low down and revs with a zip to the limiter. In fact such is the acceleration, the glorious noise and the sheer enjoyment you get from this engine that you can't help asking yourself if you'd bother with the 380bhp 3.8-litre engine in the 'S' version. Hooked-up to the 7-speed PDK 'box, as it was on our test car, the C4 feels plenty fast enough.
There are other subtle differences too, chief among them a steering rack that is just a shade heavier, making the C4 feel a little less keen to change direction. But on unfamiliar roads - and even though I'd literally driven to the airport in a C2S - the C4 feels very, very close to its rear-drive sibling. So close you might begin to wonder why you'd bother...
PLUS: Four-wheel drive system works superbly in low-grip situations and there's little penalty in terms of weight or on-limit dynamics. Usual 997 strengths - performance, brakes, grip and balance - are intact
MINUS: A trace more understeer than the C2 or C2S and a bit of agility is lost. Counter-intuitive PDK shifters are awkward to use
Porsche spends a great deal of time and money developing the four-wheel drive version of its Carrera. Its brief is simple: in the dry it should mimic the behaviour of the standard Carrera and in the wet bring added security and traction.
But the simple brief has a not-so-simple solution, involving the electronically controlled PTM (Porsche Traction Management) system from the Turbo and a standard-fit rear limited-slip differential.
The control unit that determines how much power to distribute between front and rear axles is a work of genius - not only measuring wheel speeds and lateral forces but also taking account of the steering angle before shuffling the torque. The aim is to prevent under- or oversteer before they occur, but if the car is sliding and you're already applying corrective lock the C4 will work with your reactions to bring things under control more smoothly and more quickly. And all this in no more than 100-milliseconds.
Despite such technological brilliance it's a sad fact of life for Porsche's chassis and transmission engineers that many customers are almost certainly going to choose the C4 on looks alone. The old school reflector strip across the back split opinion (I love it, many didn't) - but the wide body from the Turbo and GT3RS is a universal hit, accentuating the 997's curves without looking OTT. If you love the look then the circa-Pounds4000 premium Porsche wants for the C4 over the C2 is money well spent. Whether its multi-plate clutch in the front axle, PTM system and rear limited-slip diff have a similarly transforming effect on the dynamics should be revealed on quiet roads near Berlin and a Michelin test facility located on an ex-Cold War Russian airbase nearby.
Unfortunately the road driving on offer is restricted to roads that are either straight and very smooth or so badly surfaced that driving quickly is out of the question. On the few sequences of corners we do find the C4 feels agile and grippy, with just a shade more understeer than you might find in the standard Carrera. The wider rear track and huge 295-section (305-section for the C4S) tyres give the rear axle enormous grip so its no surprise that the front pushes wide first when you start dipping into the 3.6-litre, 340bhp (345PS) flat-six. I should mention that the new direct-injection unit feels strong and punchy low down and revs with a zip to the limiter. In fact such is the acceleration, the glorious noise and the sheer enjoyment you get from this engine that you can't help asking yourself if you'd bother with the 380bhp 3.8-litre engine in the 'S' version. Hooked-up to the 7-speed PDK 'box, as it was on our test car, the C4 feels plenty fast enough.
There are other subtle differences too, chief among them a steering rack that is just a shade heavier, making the C4 feel a little less keen to change direction. But on unfamiliar roads - and even though I'd literally driven to the airport in a C2S - the C4 feels very, very close to its rear-drive sibling. So close you might begin to wonder why you'd bother...
PLUS: Four-wheel drive system works superbly in low-grip situations and there's little penalty in terms of weight or on-limit dynamics. Usual 997 strengths - performance, brakes, grip and balance - are intact
MINUS: A trace more understeer than the C2 or C2S and a bit of agility is lost. Counter-intuitive PDK shifters are awkward to use
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