Ruf Rt-35 Roadster

First drive of the Ruf anniversary drop top

Photo: Ruf Rt-35 Roadster 1
September 11, 2014

It’s hard to believe that 37 years have gone by since Alois Ruf’s first tuned 3.3-liter 911 Turbo left his workshop. In retrospect, that car was a preview of many great supercars to come.

Two years ago, I drove that original NATO Green Ruf Turbo just after it had been fully restored. I also got behind the wheel of the sleek Ruf Rt-35 coupe, which had made its debut at the 2012 Geneva Motor Show in celebration of Ruf’s 35th anniversary.

Today, I am again behind the wheel of a Ruf Rt-35, but this time it’s the new Rt-35 Roadster. Although it is motivated by a turbocharged flat six, it’s actually based on the 991 Carrera cabriolet.

Photo: Ruf Rt-35 Roadster 2

On Boost
Compared to Ruf’s usual supercar engines, the Rt-35 Roadster’s flat six is in a relatively mild state of tune. A pair of less restrictive air filters were added to improve intake flow. At the other end of the engine, the exhaust system was modified to produce less backpressure. The twin VTG turbochargers were also tuned to move air at a higher rate.

To make the most of the intake, exhaust and turbo mods, the ECU was remapped to raise the boost pressure to 1.3 bar (18.9 psi). The resulting output is 630 hp at 6,500 rpm and 609 lb-ft of torque from 3,000 to 3,500 rpm. This is an increase of 70 hp and 93 lb-ft of torque over the factory 991 Turbo S engine’s 560 hp and 516 lb-ft.

The superb PDK transmission works its usual magic here, and goes through its seven close ratios with both lightning-quick speed and silky-smooth finesse. Ruf also offers a six-speed manual transmission and rear wheel drive with its Turbo models—both of which are no longer offered by from the Porsche factory on its new Turbo coupes or cabriolets.

Photo: Ruf Rt-35 Roadster 3

Since the 991 Turbo cabriolet comes from the factory with 20-inch wheels, Porsche’s development engineers were initially lacking enough room for the large rims, active rear-wheel steering, intercooler air channels and the roof’s folding mechanism. To solve this, large rear fender arches were fitted. Since Porsche coupes and cabriolets share as many parts possible, the Turbo coupe ended up with the wider flares, too.

However, since the Rt-35 Roadster is based on a non-Turbo Carrera cabriolet chassis, it doesn’t have rear-wheel steering. Therefore, Ruf had more freedom to choose where to place the intercooler air channels. After a trip to a wind tunnel, Ruf pinpointed the spot of maximum air draw on the 991 as just above and behind the rear wheel arches, which is where they can be found on the Roadster.

The Rt-35 cabriolet has a claimed 0-62 mph time of 3.1 seconds, a 0-186 mph time of 25.5 seconds, and a top speed of 210 mph. Since the Ruf drop top has extra convertible structural stiffening pieces, it can weigh as much as 3,615 lbs (on versions with AWD and PDK). In comparison, the 3,693-pound factory 991 Turbo S cabriolet goes from 0-60 mph in 3.0 seconds and has a top speed of 197 mph.

Photo: Ruf Rt-35 Roadster 4

To bring the Roadster drop top to a halt, Ruf uses 380mm and 350mm vented brake discs and six and four piston calipers, front and rear.

The Drive
As I enter a German village at about 30 mph, I manually select third gear and cruise along with just 1,100 rpm showing on the tachometer. Once I am through the populated area and find the open road again, I accelerate away with good initial throttle response, even from such low crankshaft speeds. The progressive thrust strengthens rapidly, and from 1,800 rpm onwards I am really cooking with gas.

On the fly, the Roadster gathers speed at a dizzying pace. The open roof on this warm, sunny day also adds to my sensory overload, as the scenery rapidly whizzes past. It is far more alluring than being cocooned in the coupe version.

Photo: Ruf Rt-35 Roadster 5

Even on 20 × 8 and 20 × 11.5 wheels shod with 255/30ZR20s up front and 325/30ZR20s out back, the low-speed secondary ride is supple. However, the ride firms up nicely as you build speed. It’s a good compromise on the admittedly above average condition country roads surrounding Ruf’s workshop.

“We have a bespoke PASM-based set up developed in cooperation with Bilstein, and this makes all the difference,” Alois explained.

The smoothness of the car’s powertrain, coupled with the taut-but-compliant ride, is very deceptive and leads you to believe you aren’t going as fast as you actually are. In reality, you are covering ground rapidly! The true reference points here are the rate at which traffic is gobbled up and a glance at the speedometer to see the needle pointing at big numbers.

Photo: Ruf Rt-35 Roadster 6

The progressive nature of the engine means that there are no surprises when you start to play with the beautifully balanced handling and immense mechanical grip.

You can command a lower gear with a tap of the left paddle shifter in the blink of an eye and kick out the tail of this rear-drive car exiting a slow bend. Thankfully, the onset of full boost is progressive enough that you will never be surprised by a sudden rise in power or torque.

That, of course, is with all the electronic safety nets disengaged. With them hovering over you as a guardian angel, twenty-first century niceties like torque vectoring are there to help you make it around each corner safely, even when you really lean on the car’s cornering abilities.

Photo: Ruf Rt-35 Roadster 7

True to its Roots
Back at base, I sit in this amazing adrenaline pump of a car for a few minutes as the idling flat-six motor cools off from my back road jaunt.

Estonia Ruf, Alois’s wife, chose the traditional blue checked cloth centers for the beige leather interior. Not only does it match the metallic blue paintwork well, but it also establishes a strong connection to the Porsches of yore.

The Rt-35 is a landmark car that looks forward and back at the same time. It has lots of traditional styling cues, yet it’s also engineered to provide the most in modern technology. And in drop top form, it’s even more viscerally satisfying than the coupe.

Also from Issue 223

  • 1,000 Miles in a 991 Turbo S
  • A Brief Golden Age: The 917
  • Market Update: 1974-89 911
  • Street Fighter 904
  • Profile: Klaus Bischof
  • Four-Cam Speedster
  • A flamethrowing 993 GT2-bodied 930 racer
  • Coming Home: Le Mans
  • Explained: Direct Fuel Injection
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