- The 2014 BMW M3 sedan and the 2014 BMW M4 coupe will deliver 424 horsepower from a mostly new, twin-turbo 3.0-liter inline-6 engine.
- The lightest version will weigh less than 3,307 pounds, while there will be "well in excess" of 369 pound-feet of torque.
- The new M models are set to launch in January at the 2014 Detroit Auto Show.
MUNICH, Germany — With BMW giving an insight into the future of the 2014 M3 and the new 2014 M4 coupe, Edmunds can finally confirm the worst kept secret in automotive history: The V8 has been evicted from the M3's engine bay.
Due to be launched at the 2014 Detroit Auto Show in January, the M3 sedan and the M4 coupe will deliver 424 horsepower from a mostly new, twin-turbo 3.0-liter inline-6 engine. The lightest version of the new cars will weigh less than 3,307 pounds, while there will be "well in excess" of 369 pound-feet of torque to help shove it all around.
BMW says the new engine will be capable of delivering 0-60-mph times in the low 4-second bracket.
M engineering boss Albert Biermann expects more than 60 percent of the combined sales will go to the two-door M4, with 30 percent for the four-door M3 and 5-7 percent for the late-arriving M4 Cabriolet. Both the M3 sedan and the M4 coupe will go on sale in the spring.
All models will be available with a choice of a new, stronger six-speed manual (derived from the 1M Coupe's 'box, but with a twin-plate clutch, stronger gears and rev-matching added) or a dual-clutch transmission that is actually faster but adds around 60 pounds.
The manual gearbox is unashamedly aimed at U.S. customers, with Biermann pointing out that more than 20 percent of U.S. M3 buyers took pride in changing their own gears.
To get this drive to the rear differential, with its in-built locking unit that now has a drift-recognition system that switches the diff to fully locked, M developed a one-piece carbon-fiber propshaft that adds stiffness, reduces rotational inertia and saves 11 pounds.
While Audi Quattro and Mercedes-Benz's AMG divisions continue to pursue all-wheel drive, Biermann said the junior Ms will remain rear-drive, even into the next full generation.
"To accelerate out of corners, it is so fantastic with this concept that it's not needed.
"People quote Audi, but look at Audi. They have no possibility to make a rear-wheel-drive car so they might as well do all-wheel drive."
M has confidence that the chassis will impress buyers, but knows they will always come for the engine. Loosely based on the 1M Coupe's six-cylinder engine, the S55B30 unit will rev beyond 7,500 rpm, even though the torque peak will be available from around 2,000 rpm and the power peak arrives around 5,000 rpm and holds to 7,300 rpm.
BMW insists on calling it a high-revving engine, though the torque curve indicates a flat, early performance delivery rather than the sweet spinning of the outgoing motor.
Weighing 452 pounds fully dressed, the engine is 22 pounds lighter than the V8 it replaces, even with its pair of Honeywell turbochargers and indirect intercooling system attached. The two turbos generate around 18 pounds of boost pressure, which is then fed through the intercooler into chambers with an 80mm bore and an 89.6mm stroke.
The turbochargers don't use twin-scroll technology, but combine with variable valve timing and lift and direct fuel injection to deliver more power than ever before in an M3 but with emissions around 30 percent lower than the E36 M3 of 1992.
There are four exhaust pipes, too, all of which are permanently open, though an electronically activated flap can short-circuit the rear silencer at the push of a button for more sound.
Even though the 435i's suspension was a significant upgrade over the 335i sedan, the M3/4 has gone even further. M has developed unique front and rear suspension hardware, with the rear end's five-link system attaching to a steel subframe that bolts directly to the body.
It has stiffened up the front end with a combination of forged aluminum suspension components and a thin carbon-fiber strut brace that looks like a giant boomerang, all accommodating M's first electronic power steering system.
Holding up the standard M3 and M4 will be a set of 19-inch forged alloy wheels clad in Michelin Pilot Super Sport 255/35ZR19 tires at the front and 275/35ZR19s at the rear.
The standard brake package will include steel rotors with four calipers at the front and two at the rear, though there is an optional carbon-ceramic disc setup that uses six pistons for the front end and four at the back.
The net result is a set of track dimensions that are nearly 2 inches wider than the 435i's (and almost as wide as the M5's), which demanded unique body panels everywhere. The only panels shared with the 435i are the doors.
While the large rear three-quarter panel is steel, the hood and the front quarter panels are aluminum and the roof and the deck lid (including the aero-friendly Gurney flap) are made from carbon fiber.
"We didn't aim for the previous-generation M3 as the target weight," M's Michael Wimbeck said. "We aimed at the previous, previous generation that was 3,296 pounds."
While the M3 and M4 will retain M's signature 50/50 front-to-rear weight distribution, Wimbeck admits it was a close thing.
"Generally it's 50/50. It's easier to find parts at the rear of the car to make the car lighter but then you have to chase more and more expensive parts in the front to keep the balance."
Edmunds says: As much as we hate to see the high-revving V8 go, BMW looks to have provided more than a few reasons to get excited about the return of the M3's straight-6.