2019 Mercedes-AMG GT4 performance review

There are many unusual sensations that fight for your attention while driving the 2019 Mercedes-AMG GT4, but the most surprising is undoubtedly the breeze.

Its location is the primary reason it dominates the senses, a strong stream of cool, fresh air being sent straight up the legs of my race suit in an attempt to keep steering wheel attendant temperatures under control.

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Air-conditioning might seem a strange inclusion in a racing car, but it’s important when the GT4 may be driven at maximum attack for hours at a time and by owners who may not necessarily be whippet-thin professional racers.

It adds 11kg and costs a single kilowatt, though can be foregone for a cool suit which is lighter and saps no power but can be prone to failure, leaving the driver slowly basting over the course of a stint like Sunday’s roast chicken.

Thankfully, air-con has no such issues as I need all the help I can get. It might look outwardly familiar but the driving experience of the GT4 is completely alien to somehow who has only really ever driven road cars.

You sit quite reclined and deeply ensconced in a carbon safety cell lifted from AMG’s GT3 machine, Merc’s rationale being that it doesn’t want to offer a race car that’s anything less than as safe as it can possibly make it.

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With the belts tightly fastened, HANS device connected and nets to the left and right (presumably to restrain flailing limbs) it’s a fairly claustrophobic environment, and I have a weird propensity to fidget constantly when six-point harnesses are involved.

The instruction from my teacher, racer and AMG driving instructor Nathan Antunes, to start the engine provides a welcome distraction, a whirr of starter followed by a cacophonous explosion as the 4.0-litre twin-turbo V8 is woken.

Unlike road-going GTs, the GT4 has a clutch pedal, albeit a fairly apologetic one that isn’t required once moving. Fears of a bitey, capricious bastard of a thing are unfounded, with a smooth release resulting in forward motion, though the accompanying noise sounds like the tracks on an M1 Abrams tank.

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The three pedals are necessary as the GT4 also steals the six-speed sequential gearbox from its GT3 big brother. It’s lighter, smaller and much more durable than the road car’s seven-speed dual-clutch, being built to cop an unholy amount of abuse – AMG claims it’ll do 12,000 race kilometres before a check is required.

This durability is what separates the GT4 from regular road cars. Aside from the gearbox, most other bits are lifed for 18,000km except the engine, which apparently lasts, essentially, forever. “We tried to destroy an engine on the dyno and we stopped at 50,000km,” explains Stefan Wendl, head of Mercedes-AMG customer racing.

Key to its longevity is its standard nature. Whereas the GT R road car produces 430kW, the GT4 maxxes out at the 375kW we’re using today, while running as low as 295kW depending on the standard of the competition, nine boost maps allowing various power levels to achieve balance of performance.

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Factor in a 150kg-odd diet, however, and the GT4 certainly doesn’t want for straight-line pace, particularly as the brutal blend of noises envelopes you like a warm blanket. The uncorked V8 mixes with straight-cut gear whine, the metallic clack of gear changes and the impatient rattle of the diff in tight corners as it awaits the next throttle application.

The car has been pre-warmed so the slicks are up to temperature and, satisfied I’m not a complete liability, Antunes begins to coach me through how to drive the GT4 properly. With 305mm-wide slicks all round grip is plentiful, but the effective use of the electronics – again, lifted from the GT3 car – is key to exploiting the car’s abilities.

A pair of knobs adjusts the ABS and traction control systems through 12 settings. The latter is pretty self-explanatory, allowing more wheel-slip as the system is relaxed; set to eight it’ll allow oversteer slides on corner exit if you’re too eager with the throttle.

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Understeer is the predominant characteristic, though, so to overcome this you hit the unassisted brakes HARD to trigger the ABS, pinks and purple lights flashing on the instrument display to indicate you’ve done so.

Carry this brake pressure into the turn and the GT4 turns beautifully; release it too early and the front will push wide of the apex and delay throttle application. Finding the balance isn’t easy but the process is incredibly rewarding.

It’s an unbelievable machine. The harder it’s driven the better it gets and suffers no performance degradation, unlike the driver. The experience is mentally and physically taxing and after seven or eight flat-out laps fatigue starts to creep in, which is a good sign to park it.

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The GT4 might look like its road-going siblings but it’s a completely different animal. For track use there is just no comparison between this purpose-built racing car and even the most track-focused production cars.

AMG GT4s are sold direct from Germany so the price depends slightly on exchange rates, but the fact that it’s roughly equal to the GT R – and half the price of a GT3, which is remarkably similar to drive according to those in the know – makes it an absolute bargain.

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2019 Mercedes-AMG GT4 SPECS
Engine: 3982cc V8, DOHC, 32v, twin-turbo
Power: 375kW
Torque: 650Nm
Weight: 1390kg
0-100km/h: 3.5sec (est.)
Price: $350,000 (approx..)