2015 BMW M4 Coupe
The new-generation M car—which gets its own chassis code for the first time, F82—sheds its predecessor’s naturally aspirated 4.0-liter V-8 in favor of a quintessentially BMW straight-six. BMW has affixed the "TwinPower" moniker to the all-new, M-developed engine; the badging is applied to BMW’s gas and diesel turbocharged engines, and can refer to single, twin, or triple turbos, single or multiple dual-scroll turbos, or a turbo with variable inlet geometry. The M4 is fitted with a pair of Mitsubishi-sourced turbochargers.
The M4’s 3.0-liter unit, code-named S55, can rev up to 7600 rpm—a remarkable achievement for a turbocharged mill. The twin-turbo six-cylinder is rated at 425 horsepower from 5500 to 7300 rpm, while torque tops out at 406 lb-ft from 1800 rpm. Those are increases of 11 horses and 111 lb-ft of twist versus the V-8–powered M3. The standard transmission is a six-speed manual, which automatically revs on downshifts. The optional transmission is a seven-speed dual-clutch automatic, which delivers quicker shifts in exchange for additional weight.
BMW says that the 0-to-60-mph sprint takes 4.1 seconds with the six-speed manual, and the dual-clutch drops that number to 3.9. (For reference, the last M3 we tested came equipped with a stick and we managed a 0–60 time of 4.3 seconds.) Top speed is governed at 155 mph, but we believe that there will be an option to raise that limiter to 174 mph. Despite the impressive gains in output and claimed performance, the Bavarian automaker says that the M4 will be 25 percent more efficient than the model it replaces.
The loss of two cylinders certainly aids the quest for improved efficiency, but a strict diet played a role, too. BMW says that it cut 175 pounds from the E92-generation M car—the F82 is said to weigh exactly as much as an E46 M3. No curb weights were provided, but we expect the M4 to weigh in at 3400 pounds. The Bavarians’ claim that the new engine is just 20 pounds lighter than the V-8, so the remaining 155 pounds of savings comes from structural changes, lightweight seats, and a liberal use of carbon fiber—including for the roof panels.
Befitting the unique chassis code, M GmbH also has significantly reworked the M’s underpinnings versus the 435i. The control arms are lighter and stiffer, the rear subframe is bolted directly to the body without any use of rubber elements, and a carbon-fiber strut brace winds its way through the engine bay. The new car comes with an electronically controlled rear differential called Active M Differential, borrowed from the M5 and the M6. Eighteen- and 19-inch wheels will be offered, and they’ll be be wrapped in 255/35 rubber up front and 275/35 in the rear. The M4 uses an entirely new electric steering system that offers the requisite driver-selectable modes of Comfort, Sport, and Sport Plus. Carbon-ceramic brakes, the same as those found on the M5 and M6, and an adaptive suspension are available as options.
The M4 looks every bit as aggressive as its spec sheet indicates it will be. It has a wider track than the base 4-series, the front end is dominated by massive intakes, and the traditional power-dome is as muscular as ever.