Porsche 911 (991) GT3


Debut: 2013
Maker: Porsche
Predecessor: 997 GT3



 Published on 18 Aug 2013
All rights reserved. 


When the first 911 GT3 was introduced in 1999, it was supposed to be a homologation special that only hardcore, part-time gentleman racing drivers would buy. However, its sharp handling and high-revving engine quickly earned it the fame as the best-driving Porsche of all – and probably the most exciting sports car in the world. In the next 13 years, 14,145 GT3s were sold in 4 generations. The unexpected success drove the management to make it a permanent model like Carrera and Turbo. In the latest 991 generation, it will take an even more important role…

Since the very beginning, the GT3 had many racing genes. For example, its so-called "Mezger" engine, designed by motorsport department head Hans Mezger, was originated from the racing unit that powered 911 GT1. Its aero package and weight saving measures were closer to race cars than road cars. However, the new 991 GT3 marks a big departure from its predecessors. This can be seen in many areas: 1) It switches to a brand new 3.8-liter flat-six based on the direct-injected unit of production Carrera S; 2) It abandons traditional manual gearbox for a 7-speed dual-clutch PDK; 3) It is no longer a striped-out edition. Full equipment ensures a day-to-day practicality matching other 911s; 4) It employs an electrical power steering like the regular 991; 5) It introduces gadgetry 4-wheel steering, the first for Porsche. All these sound very un-GT3, don't they?

It goes without saying that the 991 GT3 is larger than the old car. Its wheelbase is 95 mm longer, while overall length and width have grown by 85 and 44 mm respectively. The chassis is constructed as an aluminum-steel hybrid structure, whereas most external panels are aluminum sheets. Larger front intakes, deeper air dam and skirts and a fixed rear wing mark it out from the regular 991 Carrera S. Compare with the latter, its rear body is 44 mm wider as it adopts the body shell of Carrera 4.



Despite of the lighter construction and a lighter engine, the use of PDK gearbox and 4WS, among others, lifted its kerb weight by 35 kg to 1430 kg. The PDK alone accounts for 30 extra kilos.

Speaking of the PDK, it differs from the applications in other Porsches by using 7 closely stacked ratios instead of 6 normal ratios plus an overdrive. This mean the 196 mph top speed is reached at 7th gear.

The new 3.8-liter engine shares its block and crankcase with Carrera S, but it gets the usual treatment of GT3, such as titanium connecting rods and lightweight forged pistons, to enhance revvability and throttle response. The cylinder heads are new, featuring rocker arms instead of tappets to cut weight. Direct injection and the addition of variable intake valve lift (the "Plus" part of VarioCam) ensure higher combustion and breathing efficiency. As a result, the new engine is capable to rev to 9000 rpm, 500 rpm higher than the last GT3 3.8 and GT3 RS 4.0. It is rated at 475 horsepower at 8250 rpm, 40 ponies more than the old GT3. Porsche engineers admitted its output rating is conservative and the actual figure is closer to 500 hp. Maximum torque of 324 pound-foot is the same as Carrera S. Better still, the new engine is 25 kg lighter than the Mezger engine, largely offsetting the extra weight of the PDK box, so the new car is hardly any more tail-heavy.

According to official figures, the new GT3 can sprint from 0 to 60 mph in merely 3.3 seconds, down from 4 seconds flat. It is also a couple of tenths quicker than the GT3 RS 4.0, thanks largely to the faster gearshift of PDK (which takes as little as 100ms on upshift) and its associated launch control. 0-100 mph sprint takes 7.5 seconds, compared with 8.2 sec of the old GT3 and 7.9 sec of RS 4.0. Top speed, however, barely inches up from 194 to 196 mph. Perhaps more important is the Nurburgring lap time of 7 min 25 sec, 15 seconds down from the last GT3 and 2 seconds quicker than even the RS 4.0! Technology improves the breed.



As before, the GT3 is served with some advanced electronic features, such as adaptive engine mounts and PASM adaptive damping. Now the list of standard features expands to active rear-wheel steering. At low-speed maneuvering (up to 37 mph) it counter steers the rear wheels to improve turn-in response and shorten turning circle. Above 50 mph, the rear wheels steer in the same direction by up to 1.5 degrees so to enhance stability. In fact, the feature contributes to the majority of time saved in Nurburgring. No wonder 918 Spyder and 991 Turbo will also adopt 4WS.

Braking is also improved. The 20-inch single-nut alloy wheels are an inch larger in diameter thus enable larger, 380 mm brake discs. As before, PCCB ceramic brakes are optional. Not that the standard steel brakes lack stopping power, but PCCB can withstand laps after laps of abuse thus is preferable for track racing.

In short, the new 991 GT3 is faster yet more sophisticated and easier to live with. In essence it is quite different to the striped-out, track-focused GT3 we used to know, even though the last 997 GT3 had already started migrating to this direction. In fact, under the pressure of competition (from Audi R8 to Nissan GT-R) Porsche has no alternatives but to develop the GT3 into an all-round high-performance model of the 911 family, and leaving the hardcore route to the future GT3 RS. That makes sense.

On the Road

Open the doors, you will see the Alcantara and carbon-fiber bucket seats distinguish it from other 911s. The same goes for the Alcantara trim on the lower half of dashboard and door panels as well as the steering wheel. Otherwise, the cabin is much the same. It has the same high-quality dashboard and center console, the same infotainment system and the same sound insulation, too. Seats aside, it doesn't lose any creature comfort.



Switch on the naturally aspirated flat-six, prod the throttle, it responds with an enthusiasm not found on the standard engine. The rev rises and falls freely as if there is no inertia. The engine runs smoothly at low rev, more so than the last GT3. It also produces slightly more mid-range torque, so the performance is more flexible. No, the 3.8-liter engine is not famous for torque, but now with 7 closely stacked ratios you can use its power band to the full. Each gearshift of the PDK transmission is completed with astonishing speed and smoothness. As a result, you lose precious little rpm in gearshift thus the acceleration is almost seamless. Such a perfect integration of engine and gearbox is rare – the only one worth comparison is perhaps Ferrari 458. The small aluminum shift paddles feel good in your hands, especially as they have shorter travel than other 911s. Having tried the new PDK, no one would miss the good old manual gearbox.

The addition of direct injection does not alter the classic sound. This is still one of the most beautiful exhaust notes in the sports car world. At low to medium rev it is a typical boxer sound, i.e. creamy yet characterful. From 5000 rpm, it intensifies, getting louder and harder edge. From 7000 to 9000 rpm is the magic moment, where it really goes mad and screams like a racing motor. The power and acceleration are relentless. By this time you would think it must be in the same league as 458 and MP4-12C!

Despite of the added punch, the 991 GT3 is significantly easier to drive than the last 997 GT3 or RS 4.0. This is not a surprise perhaps, because its chassis is 25 percent stiffer, has lower center of gravity, wider tracks and a longer wheelbase. Still, it is quite incredible that a car so focused on performance can ride so beautifully. Leave the PASM at Comfort mode, you can glide over B-roads all day long without feeling tired. It rides just as good as the regular 911, which is already a good everyday car. The new car is calmer and more stable than its predecessor, with less pitch and roll over undulations.



Then come the steering. When the 991 Carrera switched to ZF electrical power steering, some hardcore drivers thought it lost the tactile feel of the old hydraulic rack. With further fine tuning to the software, accompanied with sturdier mount and revised geometry, the GT3's system washes away all doubts. It feels really good in hands. Some of the small road surface information filtered out by the Carrera has returned, so you can tell the front end grip and road surface textures from the helm. It also feels heavier and more direct than the Carrera's. This is easily the best electrical power steering to date. Compared with the old hydraulic steering, it feels calmer and weighs more consistently. No wonder it wins the hearts of motoring journalists this time around.

However, the most important progress is how much better the new GT3 handles when you push it in a series of corners. Thanks to the effect of rear-wheel steering, the old car's understeer in corner entry and oversteer in corner exit have been largely reduced. As a result, it corners smoother, calmer and with less drama. You no longer need to fight against its rear-biased weight distribution. The new car is much more neutral and easier to handle. At the limit, its behaviour is more progressive, giving you a much wider scope to adjust its line. You can also use its deep reserve of grip more without fearing stepping over the limit. The result is faster cornering and a much more confidence-inspiring drive.

In essence, the GT3's sharp driving experience has not changed a bit in the evolution to 991 series. It is just made even more capable and easier to live with. Now it is no longer a hardcore driver's car. Every keen driver may enjoy the unparalleled driving thrills it brings if he has £100,000 to spend. Yes, this is still the best 911 of all and definitely one of the best sports cars in the world.
Verdict: 
 Published on 23 May 2015
All rights reserved. 
911 GT3 RS


It is hard to not give the new 991 GT3 RS a 5-star rating. After all, this car has more power, more grip and more downforce than the mighty 991 GT3 on which it is based, and that car won our Car of the Year title last year. The only questions we should ask are: is it a better car than the GT3 as a road car? Is it more thrilling to drive than a Ferrari 458 Speciale on track? Or more relevant to hardcore Porsche drivers, will it be more memorable than the last 997 GT3 RS 4.0?

At the first sight, the new RS looks even more spectacular, more track-oriented than the last one. Not only it is benefited from the advances of the 991-generation aluminum-intensive body, such as a wider front track, longer wheelbase and lower center of gravity, the RS is modified further. Its rear wheel arches are obviously wider than the GT3’s. This is because it is built on the wide-body chassis of 911 Turbo. Like the latter, it sports large air intakes at the rear fenders, but instead of feeding intercoolers they are adopted to produce ram effect to the engine at high speed (more on that later). Behind the rear wheels, an even larger and taller rear wing is mounted at the tail. So large that it looks as if coming straight from a race car. Ditto the new louvered air vents opened above the front wheel arches. They are undoubtedly adopted to release the air pressure built inside the front fenders thus contribute to downforce. The only thing the RS misses is a rear diffuser, for which the rear-mounted flat-six leave no space. However, that massive rear wing is more than enough. Overall, the car generates 330 kg of downforce at 186 mph (300 km/h), compared to 190 kg of the last RS.

Downforce adds grip, so do the new rubbers. They are now wider and larger in diameter – the front grow from 245/35ZR19s to 265/30ZR20s, while the rear goes from 325/30ZR19s to 325/30ZR21s – so that the contact patch area gets larger thus generate more traction and grip than ever. Moreover, the specially compounded Michelin PS Cup 2 rubbers are inherently stickier than those on either the GT3 or the last RS.



As a result, the new car feels astonishingly planted on the road. It now generates so much front and rear end grip that you need a track – and a fast one – to shake its balance. Roadholding is near race-car strong, especially at fast corners where downforce is built up. Also thanks to the planted front end, its turn-in is quicker. The retuned electric power steering feels sharper again than the GT3’s. However, to extract the most from it you need a fast race track. On public roads, it is difficult to push the car hard enough to feel its superiority over the GT3, what a pity!

Perhaps that is why the RS is not as fast as expected on the challenging surfaces of Nurburgring. So far Porsche has managed a lap time of 7 min 20 sec on a less than perfect day. They think it could be good for 7 min 17 sec, but even so it would be only 8 seconds quicker than the GT3 or 10 seconds better than the last RS 4.0. Not as quick as its spectacular looks suggested.
 
I think that has something to do with the lack of improvement on power. The new 4.0-liter engine is built on the GT3’s 3.8-liter unit rather than the legendary “Mezger” engine which retired together with the last RS. It is benefited with direct injection and variable valve lift, of course, but compared with the GT3 engine it is not a whole lot different. Yes, there is talk of revised cylinder heads, intake manifolds, valvetrains and lubrication system, but without specific details we can assume the changes are necessary to adapt to the larger, slightly more powerful motor. In particular, the GT3’s titanium connecting rods are retained. The extra capacity is achieved by lengthening the stroke for 4 mm. This resulted in the maximum rev drops slightly from 9000 rpm to 8800 rpm, although that is still 300 rpm higher than the Mezger. Unfortunately, peak output stays the same. It produces 500 horsepower at 8250 rpm and 339 lbft of torque at 6250 rpm, not a single horsepower or pound-foot more than the old engine, which is a shame. Perhaps it just tells how great the Mezger engine was. The new engine does produce more power under certain conditions, but that is achieved with the ram effect courtesy of the new intakes – at 193 mph top speed, it adds about 10 ponies.

That said, on the road the new engine is still incredible, revving freely and responsively, making great sound at high rev and producing respectable punch for a naturally aspirated motor. With reduced sound insulation, the 4.0 motor sounds even rawer and meaner than the 3.8-liter unit on GT3, although the old RS sounded angrier still. The compulsory PDK gearbox might be a let down beside the manual box of Cayman GT4, but as in the case of GT3, it is a must to match a performance level so high. Moreover, it is very responsive and accurate, loses nothing except driver involvement.



The GT3 RS is actually 3 mph slower at the top end than the GT3 due to its slightly higher drag coefficient (0.34 vs 0.33) and larger frontal area. As for acceleration, it is said to take 3.1 seconds to sprint from 0-60 mph, which is as much as 0.7 sec quicker than the old car. However, that is purely down to superior traction and responsive PDK. A clearer picture can be seen from the time it takes from 60 to 100 mph, which is 4 seconds flat, or merely a tenth faster than the old car. Lack of extra power is one reason, lack of weight saving is another.

The new car weighs 1420 kg, a considerable 60 kg more than the old car. Compared with the GT3, it is merely 10 kg less, thanks to using carbon-fiber front fenders, bonnet and engine lid, a magnesium roof, plexiglass rear screen and rear quarter windows, less sound insulation, thinner door panels and fabric door pulls to offset the extra weight of wider body and larger engine. However, it keeps most features of the GT3 road car, including air-con, audio, sat-nav, PDK, adaptive dampers, active differential, rear-wheel steering and adaptive engine mounts. The days of Renn Sport representing a stripped-out 911 have gone.

On the flip side, the new car is friendlier to drive on road. Although its stiff suspension still favours race track or smooth Autobahn, ride quality on country roads is more bearable now. At low speed, the engine runs and the PDK shifts with a civilized manner you won’t expect on an RS. The cockpit is also less noisy and more cosy than the past generations. The only real compromise is the extra width of its body, which hurts confidence when slipping through narrow country roads. As a road car, the GT3 is still the more sensible choice, but the RS version is no longer painful to live with.

This dual-purpose character can be seen as a double-edge sword but it could be also its identity problem. While the GT3 works better as a road car and is fun enough on occasional track days, the new RS has evolved to the extent that it needs absolutely a track to exploit its potential. Even then it doesn’t feel as emotional or characterful as the old RS 4.0, nor it is as thrilling to steer, to listen or to watch as the 458 Speciale. Still a superb driver’s car, but perhaps not the most special in memory.
Verdict:
 Published on 17 Jun 2016
All rights reserved. 
911 R


To the hardcore fans of Porsche, the development in recent years is not comprehensively satisfying. The latest 991.2 Carrera has switched to turbocharging which has a slight but noticeable negative effect on sound and character. While GT3 and GT3 RS keep using high-revving naturally aspirated motors, they skip traditional manual gearboxes in search for maximum track performance, which robs the pleasure of pure driver control. Moreover, the big spoilers of the GT3 duo are designed for race tracks instead of road use. This means, if you want a proper road car with naturally aspirated motor and manual gearbox, you have to downgrade to Cayman GT4 – sorry, even that car is no longer available! – or look elsewhere from Lotus, Aston Martin or Corvette. Now the complaint is finally answered by 911 R.

The 911 R is a clever project. It reuses all the existing best stuffs from the GT3 and GT3 RS but packaged in a road-going body. 991 examples are slated for production and each asks for a very profitable £137,000. That’s even more expensive than the GT3 RS! Despite that, demand is so overwhelming that all cars have been sold before production begins.

The 500-horsepower, 4.0-liter engine comes straight from the RS. It is good for 8800 rpm and offers a glorious sound. This is one of the best motors Porsche ever built and one of the greatest in the world today. Partnering the engine is not the 7-speed manual you can find in lesser 911s, but a lighter 6-speed gearbox. It is modified from the 7-speeder with the overdrive ratio discarded and the last 2 ratios stretched so that maximum speed is reached at 6th. Somehow, its gearshift is also sweeter, being precise and well weighted, matching the lighter duty 6-speed manual used in Cayman and Boxster. Good news is, this gearbox will be offered in the next GT3 and RS as well.

While the engine comes from RS, the chassis of 911 R is based on the narrower GT3, including its front bumper, axles, suspensions, wheels, tires as well as the 4WS system. However, it skips the fixed double-plane rear spoiler for the retractable one of lesser 911s so to improve drag and rearward visibility. Part of the lost downforce is compensated with a new diffuser and flat undertray. Meanwhile, GT3 RS donates many lightweight parts, such as carbon-fiber bonnet and fenders, magnesium roof, plexiglass rear screen and rear quarter windows. PCCB ceramic brakes are fitted as standard to shave further weight.



Inside, the 911 R is even leaner than the GT3 duo. Apart from lightweight door panels and fabric door pulls, it goes one step further by ditching the air-con and audio system as well as 4.5 kg of sound deadening materials. There are classic-looking lightweight bucket seats up front and no rear seats, of course. All these efforts result in a kerb weight of 1370 kg, 50 kilos lighter than even the GT3 RS. The manual gearbox alone contributes to 20 kg saving.

On the road, the 4.0 engine sounds even madder than in the RS thanks to the reduced sound insulation. As always, it can be tractable and mellow at low speed and go insane at sky-high rpm. With manual gearbox instead of the lightning-changing PDK, you tend to shift less frequently and let the engine staying longer at high revs, hence more chance to enjoy its glorious soundtrack. On the downside, performance inevitably suffers a little. Porsche said 0-60 mph takes 3.7 seconds, 0.4 and 0.6 second adrift of the GT3 and GT3 RS respectively, which is quite a lot. However, in the real world the car feels far faster once its traction is established.

If you find a clean stretch of Autobahn in early Sunday morning, you will find its superior top speed. It is able to do 201 mph, the first time a naturally aspirated 911 breaking the magic mark of 200 mph. At high speed, you do sense more float and the need for constant steering correction as it lacks the strong downforce of RS.

Also because of the much less downforce generated, the suspension of 911 R can be tuned softer. The steering and 4WS are also retuned to reflect the reduced load. As a result, the steering feels much lighter and more alert, but without losing precision. The ride becomes more supple. It doesn’t feel quite as locked down to the road as the RS, but it flows beautifully over bumps, albeit with more pitch, roll and yaw for the driver to take care of. There are still vast of grip and traction afforded by those fat Michelin Pilot Sport Cup 2 rubbers, but the chassis is more sensitive to driver input. To push the car to the limit, you have to keep concentrated and deliver 100 percent. And then the car rewards you with sharp feedback and response. Yes, some of the old-school 911 fun has returned! If we talk about driver engagement instead of absolute speed, the 911 R has to be the best Porsche today.
Verdict:
Specifications





Year
Layout
Chassis
Body

Length / width / height
Wheelbase
Engine
Capacity
Valve gears
Induction
Other engine features
Max power
Max torque
Transmission
Suspension layout

Suspension features
Tires

Kerb weight
Top speed
0-60 mph (sec)
0-100 mph (sec)
991 GT3
2013
Rear-engined, RWD, 4WS
Steel + aluminum monocoque
Steel, aluminum

4545 / 1852 / 1269 mm
2457 mm
Flat-6
3799 cc
DOHC 24 valves, DVVT+VVL
VIM
DI
475 hp / 8250 rpm
324 lbft / 6250 rpm
7-speed twin-clutch
F: strut
R: multi-link
Adaptive damping
F: 245/35ZR20
R: 305/30ZR20
1430 kg
196 mph (c)
3.3 (c) / 3.0* / 3.3** / 3.1***
7.5 (c) / 7.1* / 7.3** / 7.5***
991 GT3 RS
2015
Rear-engined, RWD, 4WS
Steel + aluminum monocoque
Aluminum, carbon-fiber, magnesium
4545 / 1880 / 1291 mm
2456 mm
Flat-6
3996 cc
DOHC 24 valves, DVVT+VVL
VIM
DI
500 hp / 8250 rpm
339 lbft / 6250 rpm
7-speed twin-clutch
F: strut
R: multi-link
Adaptive damping
F: 265/30ZR20
R: 325/30ZR21
1420 kg
193 mph (c)
3.1 (c) / 3.3* / 3.0* / 3.4****
7.1 (c) / 7.4* / 6.8* / 7.8****
991 R
2016
Rear-engined, RWD, 4WS
Steel + aluminum monocoque
Aluminum, carbon-fiber, magnesium
4532 / 1852 / 1276 mm
2457 mm
Flat-6
3996 cc
DOHC 24 valves, DVVT+VVL
VIM
DI
500 hp / 8250 rpm
339 lbft / 6250 rpm
6-speed manual
F: strut
R: multi-link
Adaptive damping
F: 245/35ZR20
R: 305/30ZR20
1370 kg
201 mph (c)
3.7 (c) / 3.4*
7.7 (c) / 7.4*




Performance tested by: *C&D, **Sport Auto, ***MT, ****Autocar





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