Ruf builds A bigger, Badder GT3—one with 3.8 liters 445 horsepower, and wild bodywork.

Photo: GT3.8
August 4, 2007

If Ruf’s Rt12 is the answer for 911 Turbo enthusiasts who want close to 700 bhp in their ultimate autobahn stormers, then devotees of normally-aspirated 911s will find Ruf’s interpretation of the 997 GT3 and its new RS derivative in the RGT.

The first 911 to wear those three letters on its decklid was based on the 2000 996 and was also the first normally-aspirated Ruf car to wear aggressive body styling. Based on the first-generation factory GT3, with power bumped from 360 bhp to 385 bhp, this car wore the R-GT label. 2004’s Ruf R-GT RS was based on the 996 GT3 RS and was rated at 395 bhp. To differentiate the generations and fit in with Ruf’s current nomenclature, the 997-based car is called RGT and is based on the current GT3 — with some RS in the mix.

Of course, just how much GT3, RS, or even Carrera flavoring is involved will be decided by each customer — because every Ruf car is built to order. In basic trim, the RGT starts off as a better appointed GT3-style car with more aggressive looks that reference the 993 GT2. The interior, however, is a different matter. We’ve seen some pretty wild colors used on the interiors of Ruf test cars in the past, but this 911’s interior is subdued. Ruf’s demonstrator features a lightweight interior trimmed in acres of blue leather. Unlike the GT3 RS, with its cockpit half-filled with a loud erector set of a rear cage, the RGT gets a Ruf Integrated Roll Cage as standard equipment, which mostly hides its bars inside of the pillar trim. You get the benefits in safety and stiffness without having to look at bars or worry about a helmetless head hitting them should the worst happen on the road — and bolt-in cages don’t offer the same benefits to rigidity welded-in ones do.

Photo: GT3.8

Subdued isn’t the word that comes to mind with regards to this RGT’s exterior, however. That starts with its shimmering pearlescent finish, which changes from one color to the next depending on how the light falls onto its surfaces. After beating Porsche to the punch on crazy 1970s colors with his R-GT RS in 2004, Alois Ruf has now decided to try two new directions with paint offerings. The first is this multi-color “flip-flop” treatment, the second a re-interpretation of an old idea Alois Ruf made famous. Years ago, a Ruf prototype wore flat-green military drab and was quickly dubbed “the NATO car.” People have been asking about that 911 ever since, says Alois. That’s prompted him to make all current Ruf colors available in a matte finish. The Rt12 in the small showroom when we arrived wore a matte finish and reminded us of the nitro paint on early 356s.

Then there’s the RGT’s styling itself. Subtle it is not. Up until the debut of the CTR2, Alois was conservative in terms of body styling additions for his cars, appealing to like-minded clients. However, the success of Porsche tuners with extrovert styling meant the demand for show as well as go began to affect Ruf cars. From the 993 and 996 generation onward, Ruf cars have taken on distinctive front and rear bumper/spoiler designs. The RGT’s nose has a built-in spoiler for aerodynamic stability and big intakes to provide the intakes for radiator cooling. On an equally practical level, its aggressive face is good for clearing the fast lane of the autobahn.

A new rear engine lid provides better venting than a stock 997 and is comparable to the GT3’s design. As with the factory 996 GT3 RS, 997 GT3, and 997 GT3 RS, the quoted dyno figures do not take into account the supercharging effects of the ram air intake on the engine lid, which only works at high speed. Porsche claims another 15 bhp from this effect, but Ruf is only willing to put his name to a more conservative 10 bhp. The big rear wing balances the looks and also saves the weight and complexity of a motorized spoiler. It is three-position adjustable via a bolt-and-hole system — with the most extreme rake for use on tracks where downforce is critical. However, if you are going to use the more aggressive angles, Alois Ruf recommends rebalancing the RGT aerodynamically with an optional front splitter.

Photo: GT3.8

The competition-based 3.6-liter flat six in the latest 997 GT3 RS leaves the factory making 415 bhp at 7600 rpm and 298 lb-ft of torque at 5500 rpm. Alois Ruf feels that an engine without a supercharger or turbocharger strapped to it should have a decent cubic capacity and 3.8 liters was his target. The GT3 3.6 is stripped before new 102-mm diameter Mahle pistons are attached to a fully balanced steel crankshaft via lightened titanium connecting rods. The stroke remains 96.4 mm, but displacement goes up to 3746 cc with the same 12.0:1 compression ratio utilized by the standard 997 GT3.

Deeper breathing comes thanks to subtle improvements from a custom set of high-lift camshafts and a sport exhaust system. The Bosch Motronic ME 7.8 ECU is remapped to cope with these changes and for a single-mass flywheel borrowed from the GT3 RS. The lighter flywheel means the ignition timing can be more aggressive at low rpm. The result, says typically conservative Ruf, is 445 bhp at 7600 rpm and 310 lb-ft of torque at 5100. To put this in perspective, 445 bhp from a normally-aspirated flat six was unthinkable back in 1988 — when Porsche’s 3.3-liter 911 Turbo made 282 bhp and Ruf’s own twin-turbocharged, 3.4-liter CTR Yellow Bird was rated for 469 bhp.

The Ruf RGT is capable of rocketing from rest to 62 mph in 4.2 seconds before reaching 124 mph in a total of 13.5 seconds. Top speed? An impressive 196 mph. None of these numbers will beat the old Yellow Bird, but more frontal area, more weight, and a lot less torque make that unavoidable. The payoff is the RGT’s docile behavior in normal driving. It pulls smoothly from 1200 rpm in sixth all the way to its top speed — yet remains a car you can conceivably enjoy daily, something no one will ever say about the original CTR.

Photo: GT3.8 1

Weight has become the watchword for car enthusiasts of late, and an even more important one than “power.” Porsche says the standard GT3 weighs 3,075 pounds, while its GT3 RS is supposed to check in 44 pounds lighter. With aluminum hood and doors, Ruf says this RGT tips in at 3,163 pounds — the extra weight largely due to the IRC cage and its trim.

The factory 997 GT3’s Porsche Active Suspension Management system as interpreted by the engineers at Weissach is quite different from the one created for the “mainstream” 997s. Even so, opinions on PASM and GT3s remain diverse here at Excellence. Everyone agrees that the 997 GT3 rides well enough to be considered as a daily driver, but not everyone is convinced that PASM improves the driving experience. As for Alois Ruf? He took the decision to avoid PASM and started from scratch with conventional dampers.

To this end, he recruited longtime supplier Bilstein to develop gas-filled dampers that would deliver a good secondary ride and iron-fisted control at high speed. They are based on the well-known Bilstein PSS-9 system, with its nine-position adjustable dampers that allow for fine-tuning of compression and rebound. Ruf’s calibrations deliver a wider range of adjustment at the lower end. The dampers are matched to Eibach springs and the final setup is five millimeters lower in ride height than a GT3. Incidentally, Alois mentioned that Bilstein will soon launch a PSS-10 suspension kit, and that a Ruf version of this will be available soon after. In addition, Bilstein is also working on special dampers that will interface with the PASM system.

Photo: GT3.8 2

The result is remarkable compliance in the low-speed secondary ride, even with the 20-inch wheels and tires fitted to this RGT. I was most impressed by the way the RGT largely ignored most of the low-speed bumps on roads where I’ve tested dozens of factory Porsche and Ruf cars. Customers have the choice of 19- or 20-inch wheels. The 19×8.5- and 19×12.5-inch alloys wear 235/35ZR19 and 325/30ZR19 rubber while the 20s use 235/35/ZR20 and 325/25ZR20 Pirelli PZero tires. We didn’t sample the 19s, but mechanical grip with either combination just has to be immense — since they’re the same wheel/tire combinations that handle the near 700-bhp output of the mighty Rt12. Thus, they have no problem dispensing the “mere” 445 bhp of a normally-aspirated RGT.

While Porsche will offer you either a GT3 or GT3 RS for hardcore or very hardcore applications, the RGT can be set up for street driving and occasional track use with GT3-style suspension arms or, for serious track work, RS-style split lower arms for more extreme negative camber angles and slicks. Adjustable GT3 or RS anti-roll bars are available and installed according to the customer’s wishes.

Ruf can further tailor the character of the RGT to the customer’s proposed use. For customers who live in countries with low speed limits, Ruf offers a shorter final drive for better acceleration. The RGT we drove had the short-ratio setup, while all RGTs get a factory GT3 limited-slip differential providing 40 percent lockup under acceleration and 60 percent on the over-run. Or perhaps you want a narrow-body, all-wheel-drive GT3 — with back seats? The RGT makes it a possibility…

Photo: GT3.8 3

Nearly limitless configurations are Ruf’s advantage, and come from the process of building each RGT up from a bare shell with additions and modifications made along the way. But, while you’ll have to talk Ruf into building an RGT your way, Alois had a certain balance in mind when he cooked up the RGT. So I was determined to let the rear-drive, two-seat demonstrator explain its mission in life for itself.

On the move, the extra displacement means the engine has plenty of low-down punch, which makes normal driving a pretty relaxed affair. When you feel the need for speed, though, the light flywheel and latent torque punt the car forward, in this case even harder than you would expect thanks to the lower final drive. The bigger pistons are not significantly heavier than the 3.6 items, so the rate at which the motor picks up revs and chases the redline is hardly affected. Mid-range urge is simply incredible and the sound that accompanies it is a flat-six growl at low revs that deepens in the mid-range as the larger pistons build momentum.

With less soundproofing than the standard GT3, the RGT’s cabin is a better acoustic chamber for enthusiasts. Past 5000 rpm and all the way to the cut-out, the primal scream of the flat six is something on the other side of addictive. The reality, however, is that you’re now picking up speed so quickly that the heady soundtrack becomes merely a backdrop to other goings on — like scenery flashing past, corners, braking, and the next gearchange that’s fast approaching.

Photo: GT3.8 4

After the few kilometers it takes to really settle into RGT-land, it dawns on you that, compared to the hardcore motor, the excellent low-speed ride is something of an anomaly. And it’s only when you start to go fast and things tighten up that you realize how much of a dual nature this 997 really has. It looks brutal at rest, yet has a cosseting character when you are merely loping. It switches back to brutal if you push harder, though. Then the RGT’s thinly veiled aggression boils back to the surface, creating a 911 that hovers up the tarmac and dives for apexes in the intervening bends like a track fiend.

With mild stabilizing understeer pushing the nose wide in the tighter bends, you can trailbrake to rotate the tail on the way in and use the beefier torque curve to balance the chassis on the way out. Then the 911’s stock in trade — fabulous rear-end traction — helps you put all 445 horses down. The information from the power steering remains uncorrupted, even with 20-inch rubber. However, country roads around Pfaffenhausen feature some of the best surfaces in the world, and we know that this would not translate well to broken and badly maintained roads. In the U.S., a similar comparison exists between the good roads around Atlanta and the crumbling tarmac in the Los Angeles area. So, on that basis — and depending on where you live — we would recommend the smaller, 19-inch wheel-and-tire combination for better all-around results.

Porsche’s GT3 does what it says on the box. It’s a road racer with some sop to civilization, its RS brother moving the goalposts closer to the racer side. With a Ruf RGT, however, you get a car with a breadth of ability that reaches further towards pampering you in normal driving, yet at the other end of the scale you can have it set up to be no less aggressive than the factory’s hardest road racer. Thus, the new RGT has a unique set of values that makes it a distinctly different proposition from the GT3 and GT3 RS.

Scanning the options list, we noted that you can even have an RGT Cabriolet should you want to go that route. However, like AMG’s CLK DTM Cabriolet, this might just be a model too far…

Also from Issue 157

  • Preview: Ruf’s 700-hp, 235-mph CTR3
  • The Unpublished IROC Story
  • Driver Jack McAfee Remembered
  • A Day Inside of Weissach
  • Three 356 Concours Kings
  • Ferry Porsche’s Carrera RS 2.7
  • Survivor: The Risky Business 928
  • Market Update: 1974-89 911s
  • Interview: Bobby Rahal
  • 911 SC Targa Turns into a Speedster
  • Mess-Less Oil Filter for 924S/944/968
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