The project is internally codenamed P15, and it calls for a new flagship that will cap the company's lineup once the P1 finishes its limited production run, but carry a price tag in the neighborhood of $500k to slot in between the P1 and the new 650S.
Just how, you wonder, can McLaren possibly develop another supercar each year? Simple: underneath, they're all essentially the same. (Only we're sure it's anything but simple.) That is to say they're all based on the same carbon monocoque structure and powered by the same 3.8-liter twin-turbo V8 mated to a seven-speed dual-clutch transmission driving the rear wheels. What differentiates them is what the engineers in Woking build around that monocoque and how they tune the engine: +/- 600 horsepower in the 12C (depending on the year it was built), 640 hp in the 650S, or 727 hp in the P1 (with another 177 from the electric assist). The 911 fighter would likely develop in the 500hp range, and the P15 will probably land in the upper 600 (or lower 700) range.
McLaren confirms that the P15 would, again, be based on that same architecture. But while C/D, noting the renewed Formula One partnership between the two, suggests that it could incorporate some measure of Honda powertrain technology, McLaren's communications director Wayne Bruce dismisses the prospect as pure speculation. "The focus of the Honda and McLaren relationship right now is very much on racing." Which isn't to say that it couldn't extend to road cars at some point in the future, but though the P15, we're told, is still "some years away yet," when it does emerge, it will in all likelihood use some form or another of the M838T engine and seven-speed DCT which McLaren developed with Ricardo to power the rest of the McLaren Automotive lineup.