The 620R is built around the firm’s carbonfibre Monocell II tub. In that respect, it’s unlike the 720S and the latest Ultimate Series cars (which use the bigger, stiffer Monocage tub) but like the McLaren GT and, fairly obviously, the 570S. Like all modern McLaren road cars thus far, it has a twin-turbocharged V8 between the driver and the rear axle line. But from this point on, the differences between this end-of-the-line special and the rest of the Sports Series portfolio are many, various and significant.
While the 570S GT4 car’s 3.8-litre ‘M838TE’ engine is limited by strict competition regulations to an output of just 430bhp, it’s uncorked in the 620R to hitherto unprecedented levels. In this application, it makes 611bhp at 7250rpm and 457lb ft between 3500rpm and 6500rpm.
This uplift in output comes courtesy of reworked ECU and turbocharger management and makes the 620R the most powerful version of McLaren’s lower-level model family of this generation. It does, however, leave it some way behind key rivals, both front- and rear-engined, for outright firepower.
A seven-speed dual-clutch automatic gearbox transmits that power to the road, as do centre-lock forged alloy wheels of staggered sizes and specially developed Pirelli P Zero Trofeo R tyres. To give a genuine race car experience, McLaren also offers a set of racing slicks for track use as an option. We were offered the opportunity to fit these to our test car, but the rules of the Autocar road test dictate road-legal rubber is used throughout. Carbon-ceramic discs, with vacuum pump and brake booster technology derived from the Senna, help haul the 620R to a stop.