HIS is the comparison Mercedes-Benz dared us to do. ĎDonít bother with a standard 911,í they said, as if suggesting it would be no contest. ĎGo for the raciest road version, the GT3. No, seriously: we want to know how our new AMG GT supercar measures up.í
We had our doubts, to be honest, since the Porsche 911 GT3 is effectively a race car for the road, and the AMG GT S while it may well be hugely capable on a race track, is still more luxury sports car than road-going race car. But Benz was insistent and Porsche, of course, didnít hesitate. Name the date and the track, and weíll be there, they both said.
That track is Sandown Raceway and, even though it is the middle of winter, Melbourneís infamous weather is almost behaving. Itís cold but clear, and the track is mostly dry. And weíre about to cut loose in two of Germanyís best driving machines.
One holds the title of best driverís car; the other wants it. One has a six-cylinder engine in the back; the other a twin-turbo V8 under its long nose. One is a road car honed for track use; the other is a grand tourer with serious sporting ambition.
And yet performance is surprisingly close. Both blast to 100km/h from rest in less than four seconds, and T comfortably top 300km/h. And, as weíll soon discover, thereís little more than a second between them on a full-noise lap of Sandown.
This bold yellow AMG GT S is one of just two such cars in Australia the day of our test, three months before customer deliveries commence. Mercedes- Benz has a packed schedule of customer events and advertising shoots, so the message is clear: donít bend it. But kid gloves will not do if weíre to truly measure this lighter, faster, SLS successor against the 911 GT3.
Compared to the silver GT S on the previous pages, this SolarBeam Yellow GT S picks up the track-focused Michelin Pilot Sport Cup 2 tyre upgrade ($1200), and carbon-ceramic brakes and a fixed carbonfibre spoiler as part of the Edition 1 pack. Plus $13,500 for the paint job, probably because it contains actual solar beams.
Our GT3 arrives as it does out of the showroom, with the same pricey Michelins, $8K of sports bucket seats and the Clubsport Pack, a no-cost option that brings a half-cage, extinguisher and six-point driverís harness. It adds just 22kg to the GT3ís 1430kg kerb weight.
Even so, the Porsche is still almost 120kg lighter than the AMG. Put that down partly to the cabin, which looks like it skipped a few stops on the Porsche production line. Thereís little in here that doesnít contribute to going faster, a spartan approach to equipment that helps the GT3 win the power-to-weight battle Ė just Ė despite having a smaller and non
turbocharged engine: 141kW per tonne compared to the beefier AMGís 139kW/tonne. But when it comes to peak power and torque, the Mercís twin-turbocharged 4.0-litre V8ís 375kW and 650Nm easily beats the GT3ís 3.8-litre flat-six (350kW and 440Nm).
Despite its lesser output, the rear-engined Porsche launches hardest. The rear tyres initially spin as the clutch violently engages from a launch-control burst, but then they grip and propel the 911 to 100km/h in 3.5sec, and on to 160km/h in just 7.3sec. Itís the initial leap that gives the GT3 its advantage. The track-spec gearing helps.
By comparison, the AMGís turbocharged torque keeps the electronics busy trying to stop its 20-inch rears turning into a pile of expensive track detritus.
Once traction is restored, the Benz hits 100km/h in 3.9sec Ė one-tenth shy of the factory claim Ė before unleashing its full fury to haul in the escaping Porsche.
Tellingly, the GT S is one-tenth faster from 100km/h- 160km/h, a rolling acceleration advantage that could prove handy for flying laps.
Straight-line acceleration numbers done, itís first blood to the Porsche. Now for the real test: one of the best tracks in the land.
The 911 GT3 is a car I know well, and one I never tire of belting around a track. It feels raw, from the roar of the tyres as speed builds to the 3.8-litre boxer six that starts with a characteristic clatter and peaks with an intoxicating shriek.
Through the first left-hander, the GT3 instantly feels reassuring, a reminder of the evolution and finessing of that 911 formula. On paper it shouldnít work with all that engine hanging behind the rear axle, but it does, brilliantly. The Porsche feels chuckable, almost playful.
Thereís some understeer, which prompts me to run in harder with more weight over the nose. Coaxing the front end through slow corners is best done by going in front end through slow corners is best done by going in hard under brakes and using the weight shift to pivot the car mid-corner. That extra entry speed helps you resist the temptation to squeeze the throttle before the apex, which is guaranteed to send the nose wide and pinch you on exit.
Be patient, get it right, and the GT3 is a cornering weapon. It never feels like itís trying to unload you.
More like itís tempting you to dive deeper and go in harder, especially in the fast left-hander at the end of Sandownís back straight, the fastest part of the track.
The GT3ís clever four-wheel-steering system, which turns the rears in the same direction as the fronts above 80km/h, adds to its surefootedness.
But while the GT3ís commendable skills can flatter the driver, they also make you work for those last few tenths. Much of it is about balance, ensuring the front tyres have weight when they need it before transferring carefully to the 305mm rears.
The GT3ís 350kW peak output isnít stratospheric by modern supercar standards, yet the light body, lengthy 9000rpm rev range and tightly packed gear 9000rpm rev range and tightly packed gear ratios make it feel like itís giving you more.
Pouring through the corner off the back straight at 140km/h, the engine is so responsive a quick blip on exit adds 25km/h before you ride the kerb through the fast right-hander. Yet the chassis is unfazed by aggressively cutting that kink before you dive deep on the stoppers that kink before you dive deep on the stoppers into the tight Dandenong Rd left-hander.
You feel a direct link between your foot and the 380mm six-pot calipers as the GT3 constantly telegraphs whatís going on at ground level. The pedal is firm, like a racing car; much firmer than the AMGís.
On exit, the GT3 rears a little, weight transferring under acceleration, giving those wide rear hoops every advantage as the speedo spins quickly. Itís here the Porsche really expresses its strengths. The electronics may chime in, but only if youíre not clean with the line or youíve provoked a slide.
Then the world recedes as the engineís metallic howl dominates. What the boxer engine lacks in low-rev muscle it makes up for with top-end punch. It takes akes muscle it makes up for with top-end punch. It takes time to reprogram yourself for the high rev-limit. power arrives at 8250rpm, but the engine happily rushes beyond that. Gearshifts via the seven-speed PDK are rapid and jolty, as if adding a last desperate kick in the right direction. akes it. Peak ily eed perate
DESPITE differences in mechanical layouts, these cars share technology designed to improve response and handling, and reduce lap times.
Active engine mounts can be stiffened to reduce engine movements when applying the throttle, to improve stability and handling on the limit. For road driving, they can be softened to improve NVH and comfort.
The AMG GT S also gets an active rear wing, but our Edition 1 model Ė which also has a carbonfibre roof and various high-gloss elements Ė gets a fixed rear wing instead.
PORSCHEíS extensive 911 line-up is legendary, with up to 20 models common. The current GT3 is the hardest of the lot, at least until the arrival of the more powerful GT3 RS.
For now there are only two versions of the AMG: the regular GT (which isnít sold here) and the more powerful GT S. But even more potent versions are on the way. Mercedes has only already revealed the track-only GT3, and some of the lessons learned in developing that car will be put to effective use in an inevitable road-going Black Series version.
The Porsche fires towards the finish line with one final demonstration of traction and control, adeptly dealing with undulating ripples as the last corner opens onto the straight. And across the line in a time of 1min 19.22sec.
Now for the challenger to the GT3ís throne.
On-paper similarities between these two German beasts fall away the moment you launch the AMG GT S. The twin-turbo V8 comes on early with an almighty heave of torque. There is almost no lag, thanks in part to the turbos having been located within the V to shorten the distance the pressurised air travels.
It feels more ferocious more of the time, and thatís especially noticeable on part-throttle. If we measured these two solely by the way they shove you back in your seat, Affalterbach wins.
Gearchanges from its seven-speed transaxle arenít as whip-crack sharp as the Porscheís, but theyíre still decisive, and the distinctive exhaust crackle and boom only adds to the occasion. Dial up Race mode and the dual-clutch dumps down a couple of ratios, the V8 raising its pitch as revs climb. Even so, itís an oldschool muscular burble rather than a high-tech yowl.
Peering out the slim screen, you feel like the GT S is faster down the front straight, despite the more luxurious cabin being quieter. Thankfully, its optional 402mm carbon-ceramic brakes have the muscle to temper the ballistic acceleration. The pedal offers less travel and more assistance than the GT3ís but itís just as effective at burying the nose and shedding speed.
Into the first corner, the AMGís long snout, coupled with the extra distance between the driver and the front wheels, exaggerates the change of direction. The AMG demands you pour the steering on smoothly.
Turn-in is direct and enthusiastic despite its longer wheelbase, and the steeringís a tad light, not quite a match for the immersive Porsche. The GT S is deceptively quick mid-turn, poised and composed, and the rear end is well planted.
This rock-solid composure works beautifully through the tight right-left-left. But where the Porsche lets you stomp the accelerator out of corners, the GT demands a more judicious squeeze to ensure its 650Nm doesnít trigger the electronics. As good as its ESC tuning is, it can handicap exit speed.
Even though it all but matches the Porsche from 100-200km/h, it doesnít carry as much speed through the slowest corner, so it enters the back straight at a disadvantage and must play catch-up. And then its additional weight Ė and stiffer suspension Ė demands more respect when clipping the ripple strips at high speed before lunging into the tight left.
Accelerating out of the tighter corners, the Mercedes feels decisively quicker, that final run to the line wringing everything out of the V8ís massive (210Nm) torque advantage.
The data tells a very different story, though. The 1min20.83sec lap time is 1.6sec slower than the GT3ís.
On that basis, this would seem a mismatch, but the GT S is far from embarrassed. In fact, our track trace shows the Mercedes is within a hair of the 911ís midcorner pace and peak speeds on the straights. In a few spots itís even a smidge quicker.
So why did it set a slower time?
The Porscheís, track-focused gearing (itís claimed to use 32 percent more fuel) and slick gearchanges help.
Equally, the GT3ís skilfully tuned (and lighter) chassis Ė communicative and malleable to the very end Ė helps the driver extract every possible tenth.
The AMG GT S canít quite match the transparency and composure of the 911 GT3 at the edge of its performance envelope. Itís fantastic up to nine-tenths.
But the Porsche continues to communicate seamlessly all the way to its limits, whereas the GT S becomes a fraction distant, a little less malleable.
Itís in that final couple of percent that Porscheís many decades of finessing the 911 make the difference. The GT3ís steering is slower yet more predictable, and its brakes are firmer but more communicative. This added bandwidth delivers more space in which to work at the limits of adhesion.
The genius of the GT3 is in creating a convincing analogue response from its torrents of digital data.
Itís hard to fathom the hours of calibration that have gone into making its four-wheel-steer system feel so natural, despite it switching tack at 80km/h.
Yet there it is, just one of a forensic array of marginal gains that result in it besting the AMG through every sector of a Sandown hot lap.
In fairness, Porsche has been perfecting the 911 concept for more than half a century, whereas AMGís career as a supercar maker arguably started with the SLS in 2010. It deserves considerable kudos for clambering up a vertiginous experience curve and running the GT3 so close in this track test. Mercedes- AMG has managed to do what so many others havenít: genuinely challenge Germanyís performance champ.
The GT S is the fastest, most engaging AMG weíve driven, by some margin. Where AMGs have often been largely about the engine, the GT S brings the dynamic capabilities to harness its prodigious grunt.
But it still fell a fraction short. Yet again, the Porsche 911 GT3 proves just how special it is: a master of the racetrack, happy to take on all challengers. And itís still the king. But with Mercedes having revealed its track-only GT3, and with the learning from that car expected to filter into a Black Series street version, the question must be asked: for how long?
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