Rumors regarding what’s under the bonnet of this car center around a new, smaller block. Supposedly, BMW has lobbed a couple of cylinders off the 4.4-liter twin-turbo in the M5 and M6. The new 3.3-liter that resulted supposedly uses a tri-turbo setup and about 450 horsepower.
The V6 engine is supposed to be a brand new unit, not a tuned version of any existing engine like the straight-six in the 335i. The focus will also be on reducing emissions and fuel consumption to a significant level.