Mercedes-AMG GT3 track test

Thunder and lightening

Its forebear had a reputation as one of the most accomplished racers of its kind, but AMG has just reset the bar

Forget the mere here and now; there can be few phenomena in the history of motor sport more successful than what is known today as GT3 racing. Around the world there are better than 20 series for GT3 cars, and many more for which GT3 cars are eligible. In turn this has prompted every major sports car company – with the ongoing and curious exception of Jaguar – to field cars, knowing there is profit not only in their sale, but their repair and upgrading. GT3 racing has become the ‘go to’ place not just for wealthy patrons to get their kicks but, increasingly, for serious full-time professional racing drivers to ply their trade.

What this has meant is that despite the best intentions of Balance Of Performance equalisation measures, the cars have rapidly become ultra-sophisticated racing machines far removed from the race-tuned road cars they were a decade or so ago. 

Back then I can remember driving the new Aston Martin DBRS9 and, despite full carbon bodywork and a convincing-looking aero package, the car was a handful to say the least. It felt like a halfway house, trapped somewhere between street and circuit. A modern GT3 car is, by comparison, as a starving wolf to a snoozing labrador, so much sharper, quicker and better suited to a wild race track environment as to render further comparison entirely unhelpful. 

Indeed GT3 cars are now so quick that, were they permitted to race at Le Mans, it would be interesting to see how much quicker the ACO-approved GTE cars (some costing close to three times as much as their unaccredited GT3 siblings), would be: I’ve spoken to plenty of GT3 racers who insist it would in fact be the GTEs that would be left chasing GT3 tails, and not the other way around.

One of the most successful of the past five years has been the Mercedes-Benz AMG SLS GT3. Renowned in racing circles for its reliability and driver friendliness, Mercedes’ business plan was based on selling 75 units over five years. In the end, AMG shifted exactly 100 before calling time on production to focus on its replacement, known simply as the Mercedes-AMG GT3. It’s sitting, waiting for me in a sodden pitlane at the Misano racetrack on Italy’s Adriatic coast.

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But before all that, how do you improve a car that remained a winner until its final season, and whose performance is going to be balanced in any case? The ever-genial AMG test driver and racer Thomas Jäger is my official tour guide. He was the same person who showed me around the SLS when it was a new car six years ago, so there’s no one better placed to illuminate the difference between them.

“The engine is the same, but that’s about it,” he explains. Unlike the AMG GT road car which uses a brand new twin-turbo 4-litre motor, the racer retains the 6.2-litre normally aspirated V8 used in the SLS GT3, an engine so old Mercedes doesn’t even sell a road car fitted with it any more.

“We kept it because we know it inside out, it has perfect reliability and all the power we need.” Also the new engine’s turbos would increase fuel consumption and position ancillaries in places where they could be damaged in a crash, forcing an otherwise serviceable car to retire. The old engine is now so dependable, Mercedes says it will do 20,500 racing kilometers before needing to be rebuilt. In the SLS it was 14,000km. So that’s almost 13,000 miles of flat-out racing without having to put a spanner on it. The new Hewland six-speed transaxle is not only quicker and lighter, it’s now lifed at 10,000km, up from 7000km.

Otherwise, everything has changed. Fundamentally the new GT3 is lighter than the SLS, with a dry weight as low as 1265kg (the SLS struggled to dip below 1325kg) that can then either be ballasted up to its homologated 1285kg race weight or, in long-distance events, be fitted with extra lights, air-conditioning and a drinks system without straying over its minimum weight.

“The wheelbase is shorter by 50mm,” says Jäger. “The SLS was a friendly car but it had a slightly lazy front end, so we wanted a sharper turn in to slower corners.” The suspension kinematics are also brand new, as are the four way adjustable dampers. The SLS had simple two-way shocks. As for the air flow over and under the car, Jäger reveals the GT3 now exists at the very edge of the permissible envelope of aero performance for such a car and that overall drag has actually gone up as a result. “But,” he insists, “we have so much downforce, it is more than worth it.”

Perhaps most attention was paid to the car’s sole unreliable component, the one that links the steering and pedals, usually referred to as the driver. Probably my strongest memory of driving the SLS was just how user-friendly it was, but the GT3 takes the philosophy and puts it on a whole new plane. The cabin will happily accommodate a 130kg, two-metre tall driver thanks to not only a massive range of adjustment to the seating position and steering wheel, but also a sliding pedal box. A new Bosch display presents page after page of information more clearly than any I’ve known and includes such refinements as different colour lights to indicate whether the front or rear tyres are on the point of triggering the ABS, so there’s no excuse for ever binning the car because you got the brake bias wrong. 

Every switch and toggle is colour coded, every change to the ABS or traction control settings flagged up in big flashing lights in front of you. Airflow through the car is so extraordinarily good I can’t imagine the optional air-conditioning being worth its cost and 14kg weight unless you’re minded to triple-stint in the Dubai 24 Hours. All-round visibility is superb and reprofiled side intrusion bars make the whole getting in and out process far faster and more dignified. Such a change may be small, but it’s also smart, because the faster pitstops that will result could easily add up to whole minutes of time saved come Sunday afternoon.

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Misano is a 90-minute flog down the autostrada from Bologna airport. The circuit layout looks interesting but it’s actually rather lacking in the medium to quick corners that make cars such as this come alive. In slow corners their mass and tight differentials can make them feel a little unwieldy even in the dry. Which it is anything but today. Rain is sheeting down, enough for my German hosts to wheel out the old jokes about me putting the British weather in my hand luggage. Those I speak to about the tyres are highly complimentary about the slick Pirelli offers for the car, but have their admiration under somewhat closer control for the wets I’ll be using.

Still there’s no coming back another day, and after five or six laps slithering around in an AMG GT road car, which did nothing to inspire confidence but at least gave me some idea of which way the track went, I was duly directed to the race car.

It would be an interesting test to put a decent driver in the car and deliberately give him an ill-fitting seat, the wrong pedal and steering positions, jam his head against the roof and send him out to do a time and compare it to one achieved with an optimal installation. I reckon only the pros would be able to drive around the problem. For me, just being this comfortable in a racing car is a privilege so rarely afforded I find myself feeling entirely relaxed and at home in my environment, despite the best efforts of the weather.

The old V8 starts with a thunderclap and responds to the slightest pedal pressure, as if to remind those brought up on turbos what proper throttle response is really like. With restrictors it’s giving about 550bhp, slightly less than it had in its ultimate road-going iteration in the SLS Black Series. There’s a clutch but, as expected, it’s only used for getting out of the pits. Tug a paddle, hear the clunk as the Hewland offers up a gear and feel the clutch gently take the strain so you don’t stall: they’ve even thought of that.

It feels a little arcade-like at first. Teams can adjust how much assistance is fed to the steering but only in the garage and with the right software and equipment. For me as someone used to wrestling with old racing cars, it’s a little light. It’s also very direct which is off-putting until you’re mentally dialled in. Then it makes the car feel far more agile than its size and weight suggest, one of the key areas in which Jäger says AMG worked hardest. And once you’ve learned to divine what the car is saying to you through your backside rather than fingers, it all starts to come together even on this strange track and in this awful weather.

There’s actually not that much grip even using full wets, though whether this is down to all the rubber lying beneath the surface of the water or the limitations of the tyre is not at all clear. What is entirely evident is just how drivable the car is, especially with a set-up designed above all to keep their precious new racing car out of the wall. It wants to understeer and if you try to correct it with a dose of power the traction control will shut down the attempt immediately. But once I’d twiddled the knob to dial down the intervention a couple of notches from AMG’s preset maximum and was less uncouth with my right boot, the car could cleanly be neutralised, allowing the engine to exploit the natural traction inherent in its transaxle design.

And then, for just a couple of laps, the GT3 was bloody brilliant. Whisper it, but in a straight line the restrictors mean it’s actually not that fast – I expect something like a Ferrari 488GTB street car would give it a decent contest – but the noise of the V8 is as good as I’ve heard from a road car-derived machine, the snap of each shift as quick and clean as you could wish. And on those parts of the track where you could raise reasonable speed, it felt surreally good in those conditions, offering vast aero-assisted grip and flawless stability even when braking into a turn, at least until you’d washed off enough speed for the wings no longer to work.

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I returned for a bit of a chat because that’s what I’d been asked to do, but when they saw me grinning like a fool, they just shut the doors, checked the pressures and sent me out again. Sadly in those few minutes what had been steady rain had turned into bucketing torrents leaving the track more flooded than drenched. Suddenly this was no longer much fun. All my earlier bravado deserted me as I turned the traction control back to max without delay. But even that was not enough: any attempt actually to drive the car as you might wish to drive any racing car would cause it to snap and bite, reminding me somewhat starkly that for all its electronic trickery, stability control systems in these cars are not permitted. You couldn’t use any of its power in at least half its gears, even in a straight line.

It was no more the car’s fault than had you flung it in a lake and expressed surprise that it did not float. The track was simply not safe to drive. After one last lurch, this time when gently lifting off on the way into a quick kink, I concluded I’d learn nothing more by staying out, other than perhaps just how strong was the carbon-fibre safety cell around my body, information I thought both you and I could probably survive without.

In one way it was clearly a shame not to be able really to experience the full envelope of the GT3’s performance, but in another the weather actually did me a favour: this is a track test, and that was some test of the car and its ability to look after an amateur driver in the worst conditions in which you’d ever consider racing a car. And until the track conditions deteriorated to a stage where any race would be red-flagged, it did extraordinarily well, a true beast from end to end, but one with unwavering loyalty to its temporary master. On a quick dry track wearing a fresh set of slicks, I expect you’d have the time of your life.