Tuesday 8th November 2005


RUF RT12

Ian Kuah explores the outer edges of the envelope in this 225mph, 650bhp 911

Ruf RT12
Ruf RT12

Like a fine wine, a new Ruf model takes time to mature before it is judged fit for consumption by Porsche aficionados. But like all good alchemists, Alois Ruf has perfected the art of accelerating the timescale of his craft.

So, while the fantastic Ruf CTR2 only emerged two years into the lifecycle of the Porsche 993, barely six months passed between the debut of the 997 Carrera and the first public showing of the Ruf RT12 at the 2004 Essen Motor Show.

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The new car could quite easily have been the CTR3, but Alois Ruf decided to use the RT12 (Ruf Turbo 12) designation to commemorate the 12th turbocharged Ruf model to leave his Pfaffenhausen works. Nonetheless, the RT12 is also the fastest Ruf car ever. While the CTR reached 211.5mph in 1988 and went on to record 213mph, the RT12 will easily nail 218mph, even with the shorter of its two optional final drive ratios. The longer ratio promises 225mph.

On the way there, its 0-100km/h and 160km/h times of 3.3 sec and 6.6 sec respectively, beat the 300Kg lighter CTR’s numbers significantly -- even though at 3.6 and 7.3 sec, the 1988 car is still spectacularly fast by any standards. Beyond that, the RT12 recorded a spectacular 9.7 sec to 200km/h (124mph). “This is the first car we have ever built that can crack 10 seconds to 200km/h,” said Alois Ruf.

Engineering

The major physical difference between last year’s 996-based Rturbo 590 and the RT12’s 650bhp motor is the bump in displacement from 3.6 to 3.8 litres and the modified turbochargers. Both engines share a bespoke cast alloy intake manifold and the same enlarged throttle body. The heads are similar but the light and immensely strong titanium con-rods are different, because the 102mm Mahle pistons in the new barrels have a different wrist-pin location.

Beyond that, the cylinder-heads are also gas-flowed, while bespoke inlet and exhaust camshafts that make full use of the enlarged capacity and modified Ruf KKK K24 family turbochargers set for a maximum boost pressure of 1.1 bar are installed. When all is said and done, the RT12’s twin-turbo flat-six punches out 650bhp and 642lb-ft of torque.

The bodyshell that contains this powerhouse of an engine has rear arches one inch wider on each side than the new Carrera 4S. They are filled out by 11J x 19-inch alloy wheels shod with 305/25ZR19 Pirelli P Zero Rosso tyres, while the fronts are 8.5J x 19-inch with 255/30ZR19 rubber. Ruf offers two styles of wheel in these sizes, and both his five-spoke design and the spoked wheels with forged centres are made by OZ Racing.

The pace of the RT12 necessitates brakes with enormous stopping power and the RT12 has 380mm discs with eight-pot callipers in front and 330mm rear discs with four-pot callipers. These provide staggering retardation with progressive pedal feel.

Deploying that power with perfect control is down to the Ruf suspension kit and uprated bushes. As with all current Ruf cars, there is a choice of two suspension types, conventional and with hydraulic lift capability for customers who live in places where clearing car park ramps and other low obstacles is an issue.

The standard Ruf RT12 suspension kit is made by Bilstein. The alternative is an Ohlins system with hydraulic lift capability that increases the ride height by two inches at the touch of a button.

Driving the RT12

Customers get the choice of rear or four-wheel-drive as with all Ruf 911-based cars. Our red test car had the latter, and this is ideal for transmitting its 650bhp to the tarmac in all weather conditions. While even the 2WD only 911 with its inherently good traction is always going to have a traction edge over its rivals, with 4WD its advantage is overwhelming.

With its larger 102mm pistons, the RT12 motor has a different character from the Rturbo 590 motor. It is not quite so free-revving, and while the 590 has a really linear power delivery from idle to the cut-out, the more powerful RT12 motor has a pronounced power step around 4,000rpm when it seems to take on a second wind and pushes even harder. This is a characteristic of the bigger turbos and makes the car feel more like a civilised and very strong version of a traditional turbo motor, rather than the 7.0 litre normally-aspirated engine that we felt the 590 more closely approximates.

Our usual party trick of dropping the car into sixth gear and letting the revs fall to 1,000rpm at 50km/h (30mph), saw the RT12 pull smoothly with progressive throttle input. With torque as its strong suit, from 2,000rpm on it takes off like a rocket. Making a turbocharged engine that pulls cleanly from 50km/h to 350km/h in one gear is quite an achievement, but that is what Ruf’s expertise with twin-turbo technology is all about.

The RT12 feels solidly bolted down no matter what the road surface, no matter how hard you apply power coming out of a bend. Some of this handling panache is a by-product of the Ruf integrated roll cage, which is installed while the car is still a bare shell. This adds at least 25 per cent to the torsional stiffness of the bodyshell, making it a really stable platform for the uprated suspension.

The result is that the RT12 delivers a huge amount of driver confidence and shows just what a vital role all-wheel-drive, a stiff structure and well-sorted suspension play in rounding out the performance envelope of a 600bhp plus supercar.

Ultimate driving machine

Couple this to the supreme tractability of the motor around town and its bombastic thrust on full noise, and you have the perfect recipe for Ruf’s ultimate driving machine.