The Four Horsepowermen of the Aporschelypse: the GT3 Cup, GT3 R, RSR, and a regular ol’ everyday 500-hp GT3
It’s a mad, mad automotive world. How so? Street-legal cars have more power than race cars (or just as much). The march of technology has made commonplace reliable engines with 500 to 700 horsepower (as much as or a lot more than popular sports car series such as FIA GT3 and Pirelli World Challenge), clean emissions, and 22 mpg (10.7 L/100km) highway.
That’s the reason I find myself in the former East Germany as an invited guest of Porsche at the Lausitzring, a NASCAR-inspired tri-oval an hour outside Berlin.
Another great perk of life as track tester for Motor Trend is that I’m occasionally invited to sample factory-built trophy-chasing track weapons. A terrific facility, the Lausitzring failed to catch on with road-circuit-loving Europeans. But its twisty infield circuit is an excellent place to sample four of the latest-gen 911s—from street-legal versions to one that borders on blasphemy.
Despite driving under quite different conditions, all these 911s generate very similar horsepower from their nonturbo flat-sixes, now sized at 4.0 liters with direct-injection, solid lifters, and many improvements aimed at better efficiency and reduced maintenance. Porsche claims the metallurgy is now so good that valve adjustments are no longer necessary, making hydraulic lifters obsolete. A trick feature: An integrated oil centrifuge is employed to reduce oil foaming.
We start in Porsche’s GT3 Cup car, the most-produced GT racing car in the world (with more than 3,000 units sold in 996, 997, and 991 generations). It runs in Porsche’s 20 one-make series races all over the world. It’s so close to the road-going GT3 that it’s even built on the same production line. It’s funny—go to any track day, and you’ll find this very quick and bulletproof 485-hp machine dominating the place. While here today, it’s like a little brother.
The transmission is an air-actuated paddle- shift sequential six-speed, and yeah, we miss the involvement of the now-antique H-pattern stick, but the computer saves you from costly overrevs, spins, and crashes because it perfectly matches revs and will not allow the driver error of a bad downshift. Instead, drivers find their challenge is in the GT3 Cup’s lack of traction control and antilock brakes. It’s all on you, hero. Price: 189,900 Euros, or about $225,000 USD at today’s exchange rates.
Driving the GT3 Cup is vicious refinement. Controls, precise. Forces, violent. It rips to 8,500 rpm with whip-crack fingertip shifts. At the limit, it’s demanding, pulling strong g’s in all horizontal directions on broad Michelin slicks. It proudly wears the 911 character with a bit of tail-happiness when turning into a tight corner but changing quickly to strong understeer if the driver impetuously gets on the throttle too soon. The Cup car keeps its pilots on their toes.
This version is the most difficult to drive at the limit of the three racers I’ll drive today. Although it offers adjustable anti-roll bars on both ends, the race-valved shocks are fixed to keep the competition close. It is my estimation that the car was set with a lot of front bar to keep it stable for ham-handed journalists; I found it easy to lock an inside front tire entering the switchbacks. That familiar understeer would appear once the weight had transferred to the outside.
With the power building in second gear while leaving those tight corners, the additional torque of the 4.0-liter could hang the tail in a nice drift. The Cup car demands a lot from its driver, spending a lot of time on a knife edge of control. Perhaps this is done deliberately to enhance the level of driving involvement. But I personally would prefer the beautiful balance of the 911 street cars such as the GT3 and even the relatively simple and satisfying base Carrera.
Next we move to the 911 GT3 R, which is prepped to a more aggressive level for open sports car racing in classes such as IMSA GTD, Pirelli World Challenge, and VLN Endurance at the epic Nürburgring. This GT3’s mission is quite different. No longer a spec-series car, it goes to battle in pro races against other automakers and is built under strict rules and the dreaded Balance of Performance (BoP) criteria. These classes are red-hot right now, with many manufacturers wading into the fray. In fact, its more noticeable if a manufacturer isn’t in this series. The competition is fierce, perhaps more so than at any other time in history. A manufacturer can’t just show up and expect to win; it must be totally on its game or suffer the humiliation of backmarker status.
Surprisingly, the GT3 R engine is very similar to the street unit, generating about a rated 500 hp depending on the rules of the series it’s running. This power runs through the Porsche sequential six-speed with those ubiquitous paddles that can do no wrong.
The R can easily smoke a Cup car, but that speed comes entirely from the chassis, aero, and tires. The race modifications touch everything. The body treatment enhances downforce and reduces weight, with most of it done in carbon-fiber composite, of course. It’s still built on the “intelligent aluminum-steel composite construction” of the street GT3 RS, but if you check the specs, this homologated car is actually 20 kilograms (about 44 pounds) heavier than the more street-based Cup car. Say what now? It turns out the light components of the body and other parts allow Porsche to locate the mass more ideally, such as lower and closer to the middle of the car, and thus counteract the added mass of extra width and additional aero pieces.
All windows are polycarbonate, even the windshield (a first for Porsche). There is the unique double-bubble roof from the street RS (reducing frontal area) and a radiator repositioned to a much more protected location between the front wheels and vented through the hood—also reducing polar moment for quicker turn-in and making fragile coolers much more likely to survive on-track battles. I’ve been there in more than a few 911 race cars; a light touch to a front corner, and a sure win slips away. The heartbreakingly sweet aroma of leaking coolant is the bitter stench of defeat.
Aero tweaks are many, from an enormous splitter out front to huge, racy vents atop the front fenders and more wing (always a personal favorite). The track is widened considerably with fat front fenders and rear flares covering the ever-larger race slicks on BBS wheels. More width equals more cornering g—it’s that simple.
The 991 GT3 R still uses the sturdy strut-type front suspension like the street car, with racing versions of its ABS and traction control, as well. This creates great confidence and lets me attack the Lausitzring with times that impress my young Werksfahrer guide, Mathieu. Perhaps because of this, the 911 R was my favorite. It had quicker, sharper responses than the Cup, yet it was more hooked up, as well, more stable in the critical entry to the corner. The balance was better, the limits were higher, and with the ABS safety net, I dove deeply into the brake zones. Exiting the turns, the GT3 R seemed to have better traction, but honestly it was masked a bit by the traction control. I came out of this car pumped and ready to race. If anyone has a spare 429,000 Euros ($506,000 USD), I’ll gladly take one! But alas, time to move on. The RSR awaits.
Have you been frustrated by how the 911 clings to the tradition of the rear-mounted engine? Do you think “Finally!” when hearing that this world-class racer has repositioned the flat-six into the back seat? Have you no respect for the 50-year cult surrounding the Porsche holy scripture? Besides, rear weight is ideal for braking into and powering out of corners. So there.
Until now. The blasphemous RSR of 2017 is aft-engine no longer. Could it be a sign of the future for the vaunted sports car? Porsche engineers were mute on the subject. Just remember, this is motorsports. Victory is expected, but the FIA writes the rules. And the rules forced Porsche’s hand. Have you seen the outrageous protrusions jutting from the rear of today’s GT3-class racers? When I saw the Audi R8 and Lamborghini diffusers two years ago, I was sure they’d be dislodged in the first corner. Regardless, it means low-drag downforce, and it’s really fast. Unfortunately, having the flat-six out back puts it in the way.
This is not the first time race-bred Porsches have “positioned the engine in front of the rear axle,” as they like to say (the term “mid-engine” was never seen in the press release or heard in talking points). Every Porsche prototype has placed it there, from the 962 to this year’s overall LeMans-winning 919 Hybrid. And the limits of the 911 concept have been pushed forward before, as with the 911 GT1 that triumphed at LeMans in 1998. Don’t hate the player; hate the regulations.
This concept makes this RSR a very special 911, indeed. It’s a ground-up fresh design—even wider than the GT3 R (for more g), with a couple more inches of wheelbase—that maximizes every aspect of the rules. Another striking evolution is the use of control arms at the front axle, which, combined with the engine placement, makes this chassis racing-spiral its way ever closer to the realm of full-on prototypes. In the words of the head of Porsche Motorsport, Frank-Steffen Walliser: “While retaining the typical 911 design, this is the biggest evolution by now in the history of our top GT model.”
As with the GT3 R compared to the Cup car, the RSR will in turn wax the GT3 R. And again, it is not due to the engine, which is quite similar to the others. Rather, it’s the chassis and aerodynamic improvements. (Interestingly, the 911 Cup car probably has a better top speed due to less frontal area and downforce drag, yet it is far slower on a full lap for the same reasons.)
These racing upgrades make the RSR a pleasure to drive. It is, as you might expect, more race car, as in more stuck to the road. The challenge is to release the brake and trust the grip. The power is magnified by its light weight and traction off the corner.
At that far end of the Lausitzring straight, I found the most obvious improvement to be in the brake zone, where the aero rewards a very aggressive attack on the pedal and then an easing back as speed rapidly dissipates. Although the car is not lighter than the others, it feels it due to the grip. It’s quicker, more responsive, and not finicky like the Cup can be.
To be perfectly frank, I found the mid-placement of the engine not terribly obvious in the driving feel, a testament to how well developed the rear positioning is on the GT3 R. Walliser said the change was only 1 percent, significant in a race car, ja, ja, but not what I expected for sure. In stepping from a street 911 to a Cayman, the change is much more obvious. The real advancement is in the ground-grabbing splitter, wing, and that massive protuberance: the diffuser. In today’s racing world, aerodynamics rule the roost.
Well, that and reliability. The RSR is the most tested of any Porsche race car, with visits to circuits all over the world last year, including a climactic 50-hour test at Sebring. For two days and two hours straight, the RSR endured the pounding on the roughest place on Earth, with concrete that is older than the 911’s rear-engine layout. This emphasis and focus on quick serviceability will serve the teams well once they’re out in the real racing world. Having calculated the cost per hour to run a race car on course, I can better appreciate the 832,700 Euro ($982,000 USD) price. Precious, indeed.
Having bagged all three racing versions, I begged my way into a new street-legal 911 GT3 that happened to be parked on pit lane. The engine seemed so familiar right off the bat, that same 500-hp flat-six, but I just let the PDK do its shifting magic. The car exhibited a rare but wonderful balance: stable entering the corner and loosening up in the middle of the turn. Many other cars are the other way around, but with the GT3 powerplant out back, this handling is ideal. Drive it in deep with confidence, and then have it steer willingly for the apex. Could this be the result of an advancement in rear steer? I hope so, and we’ll learn more with the full track test of this latest generation. Stay tuned.
View more photos of these Porsche 911 race cars in our gallery: