AMG One aside, this is the most powerful Mercedes product ever sold in Australia. We test the 620kW plug-in hybrid with a little help from Mick Doohan
Mick Doohan has delivered some of the more memorable moments of my career as a motoring journalist. Some of the more hilariously outrageous ones remain locked in the off-the-record vault, but the five-time 500cc World Champion is always good company. My introduction to Doohan was at Phillip Island, a track where he claimed only one of his 54 total 500cc Grand Prix victories (Doohan’s other two local wins came at Eastern Creek which hosted the Australian Grand Prix from 1991-97).
Doohan has been a long-time Mercedes-AMG ambassador and he was at Phillip Island not long after his retirement from motorcycle racing in 1999, as the assembled journalists tested a gathering of the latest hot Benzes from Affalterbach.
At day’s end, Doohan was given his pick of AMGs to take the members of the media for hot laps of the magnificent circuit overlooking Cunningham Bay and Bass Strait. Doohan opted for a menacing CL55 AMG, and the big coupe was loaded with three journos, me in the left rear. Doohan entertained with a fast and committed outlap, but also with a casual approach to the AMG’s speed borne out of a decade in the world of Grand Prix motorcycle racing and the well-documented risks and injuries that went with it. Halfway down Gardner Straight on the flying lap, I’d asked Doohan a not very important question. I don’t recall the question, nor its answer, but I certainly remember Doohan turning in his seat to look me in the eyes as he addressed me, all while casually floating the thundering CL55 through turn one (named in his honour two years prior) with just the one hand on the wheel as the other made his point.
Fast forward more than 20 years and this time I’m in the front passenger seat of Mercedes-AMG’s newly arrived GT63 S E Performance as Doohan cruises out of pitlane at Sydney Motorsport Park. As always, he’s on it from the off, and the big AMG is bucking and squirming across ripple strips with the tyres protesting as they give up and regain grip at regular intervals.
As Doohan tips into the notoriously tricky turn five, we both spot a decently sized freshwater turtle making its way across the track towards the exit kerb. A slight reset of the throttle and tightening of his line allows the AMG to safely (albeit noisily) straddle the turtle and we all continue on our way. Doohan and I then spend the remainder of the lap discussing Cape Barren Geese at Phillip Island and the monkeys that Doohan has avoided at the Malaysian Grand Prix.
As we rapidly negotiate turn five on the flying lap, we spot the turtle well off to the right of the circuit. I remark that it’s got a decent turn of speed for a turtle, but Doohan deadpans that he’s so slow that even a turtle has plenty of time to get out of the way. Even 25 years after his last World Championship, there’s nothing slow about Doohan, nor the extremely rapid GT63 S E Performance.
With a combined output of 620kW and 1400Nm (more on this figure shortly) there’s no way the big four door could be anything other than capital-F fast. The all-wheel-drive GT63 gets off the line and to 100km/h in just 2.9 seconds, reaches 200km/h in 9.9sec and tops out at 316km/h. The GT63 is AMG’s first performance hybrid and uses a plug-in hybrid system that’s since been adopted by the C63 S E Performance that we drove on its international launch nearly 12 months ago. Here, the system combines with the GT63’s 4.0-litre twin-turbocharged M177 V8 that on its own supplies 470kW and a herculean 900Nm. The outputs of the engine are delivered to all four wheels via a nine-speed MCT gearbox and 4Matic+ all-wheel-drive system. A 6.1kWh battery pack supplies energy to an electric motor that acts on the rear axle via a two-speed gearbox. For 10-second bursts, the motor provides 150kW, to deliver the headline power figure of 620kW, but its continuous output is 75kW for a still-handy 545kW combined output. The motor also provides 320Nm which, thanks to the multiplication factor of the two-speed gearbox, delivers the 1400Nm combined figure.
Of course, a car this big (5054mm in length) and stuffed with this much hardware isn’t going to be light, and so the 2380kg GT63 S E Performance proves. The 6.1kWh battery pack – which requires 14 litres of coolant – weighs 89kg. Charging is via the onboard AC charger (rated at 3.7kW) and the electric-only range is 12km – given the capacity of the battery pack, there is no DC charging. As we found out during our cool-down laps of Sydney Motorsport Park, the system regens so quickly that customers are likely to never need to plug in.
As this was a track-only test, there’s little to report in terms of ride quality or other real-world concerns, but the GT63 rides on AMG’s Ride Control+ suspension. Ride Control+ uses multi-chamber air suspension with adaptive electronically controlled damping and automatic level control. It’s a new system for this generation of the GT63, and for the first time uses pressure relief valves to adjust damping force for each wheel. The system adjusts in milliseconds, and rebound and compression are controlled independently. Despite the mass the system is tasked with controlling, it manages to minimise dive, squat and roll even in the extremes of track driving. There’s plenty of Michelin rubber generating serious grip even on a surface that’s initially drying from an early morning shower. The road-biased Pilot Sport 4S tyres measure 275/35 ZR21 up front and 315/20 ZR21 at the rear. Obviously, a Cup 2 would help on the track, but the 4S rubber provides impressive grip and wear on SMP’s notoriously abrasive surface.
There’s not much in the way of outright feedback flowing to the driver, but the square-shouldered nature of the Michelins and the flat stance afforded by the suspension signals available grip levels if you’re attuned to the chassis. The one spike of oversteer I experience (out of turn six) is signalled early and corrected with an opening of the steering a slight throttle release. Journalists aren’t allowed to completely switch off the safety electronics and even in their most lenient setting they nibble at excesses in speed and throttle application (even down the main straight at over 200km/h). Mick Doohan was freed from such constraints and as a result, the chassis of the GT63 felt more alive, at least from the passenger seat while dodging turtles.
Again, due to the track-focused nature of this drive, we skipped through the other modes available via AMG Dynamic Select and went straight to Race. And the gearbox was flicked to manual for additional control and involvement. The vocal V8 revs freely and you need to keep an eye on the tacho so that you’re not late on a shift and stutter into the limiter. I was guilty of that once, thinking that the V8 had another thousand revs to offer.
With the full 900Nm from the V8 arriving at just 2500rpm (and staying until 4500rpm), there’s little need for torque fill, but you can feel the electric motor providing a boost out the Sydney Motorsport Park’s two slowest corners (two and eight). The rear-steering is also most noticeable negotiating these low-speed corners, providing the rear wheels with up to 1.3 degrees of steering in the opposite direction to the fronts to virtually shorten the three-metre wheelbase. At higher speeds, the rear wheels turn in the same direction as the fronts, virtually lengthen the wheelbase for additional stability, and the big AMG feels as safe as houses firing through the very high-speed turn one after breaching 250km/h down the straight.
After several sessions for each of the assembled journos, each GT63 S E Performance had completed around 30 laps and the brakes were still there on my last laps. Given that the rotors measure 420mm up front and 380mm at the rear, with six-piston fixed front calipers and single-piston floating rear calipers, you’d rightly expect performance and stamina, but slowing a 2380kg projectile from high speeds isn’t an easy task. You’re aware of that mass, but the pedal continues to sit at the top of its travel after repeated hard stops.
Though obviously not a track car, the new GT63 S E Performance doesn’t feel like a fish out of water at SMP. Indeed, it’s fast, stable and entertaining to hustle through the high-speed corners and change of direction through turns nine and ten.
Anyone buying the $399,900 GT63 S E Performance is likely to have other choices in the garage, and some might be dedicated to the track. But if not, the most powerful Mercedes-AMG product available to be registered in Australia is a surprisingly complete package.