The 650, of course, stands for the engine’s metrically measured power output, while the S stands for Sport. One could be forgiven for thinking the designation redundant in McLaren’s tiny line-up, especially since the firm confirmed that the 12C would be discontinued. The M383T-designated twin-turbocharged V8 engine in the 650S is ostensibly the same onewe know well from all of McLaren’s cars. Here in the 650S it makes 641bhp. The hardware differs from that used in the 617bhp 12C thanks to new pistons and a redesigned cylinder head. There are also new exhaust valves and the cooling circuits have been redesigned to better deal with the inevitable extra heat that comes with such a power increase.
Camshaft timings are different, too. These are said to improve both economy and throttle response, while a new exhaust system is lighter than before. McLaren’s intention was to improve the perceived response of the engine. As such, torque now builds from 3000rpm to 7000rpm rather than plateauing, so the more revs you have, the faster it feels. The engine drives the rear wheels through a seven-speed dual-clutch automatic transmission, as before. But while there are no changes to the hardware, the software has been altered to elicit faster, crisper shifts.