BMW adds X3 and X4 to high-performance M lineup
BMW has taken the X3 sports activity vehicle and the X4 sports activity coupe and given them the M treatment. Both receive a souped-up six-cylinder twin-turbocharged engine for 473 horsepower of output, with special Competition models receiving 503 horses. And both will be built in the U.S.
The 2020 BMW X3 M and X4 M will enter production in April of 2019 at BMW's plant in Spartanburg, South Carolina. They will use the new BMW M S58 six-cylinder inline engine has a crank redline of 7,200 rpm in a closed-deck design for rigid construction.
The new six-cylinder engine outputs 473 horsepower (353 kW) at 6,250 rpm and 442 pound-feet (599 NM) of torque at 2,600 rpm. This gives the BMW X3 and X4 models a 0-60 mph (0-96 km/h) sprint time of 4.1 seconds. Competition models see more boosting, pushing power to 503 hp (375 kW) and reducing the 0-60 time to 4 seconds flat, BMW says. Top speeds are electronically limited to 155 mph (249 km/h) in the standard X3 M and X4 M models and 177 mph (285 km/h) in Competition models.
The new BMW engine features wire-arc sprayed-on iron coatings on its cylinder walls for frictional loss reduction and reduced weight. The cylinder head core is 3D printed, BMW says, to create precision use of geometric forms for weight reduction and strength improvement – something that traditional casting methods in aluminum do not allow.
The M TwinPower Turbo technology used in the new engine includes two mono-scroll turbochargers, each handling three cylinders. The turbos are cooled with a water-to-air intercooler and allow high-compression in the engine. Precision injection under 200 to 350 bar of pressure for fuel:air mixture is also key to the engine's efficiency when it comes to power output.
Cooling is derived from BMW's motorsports programs. Three radiators, one large central one and two flanking "wing" radiators, are used along with additional engine oil and transmission oil coolers. The oil supply system also includes an integrated suction channel and map-controlled oil pump that can draw oil from an additional oil chamber to keep flow continual and reliable.
The exhaust system on the new X3 M and X4 M models is a true dual exhaust designed to eliminate backpressure and create a strong soundtrack, with electronically-controlled flaps producing the engine note. These flaps are controlled through the mode selection in the cockpit, so drivers can dial in more (or less) aggressive sounds as they please.
The S58 engine outputs to an upgraded eight-speed M Steptronic automatic transmission. With tuning for faster gear changes, the transmission is programmed via the drive mode selected for either spirited fast-paced shifts or smoother, more controlled comfortable shifting.
Both the X3 M and X4 M feature traction control enhanced by new programming for BMW's xDrive all-wheel drive system. Power is sent to wheels according to dynamic need, using a rear-wheel bias for most driving and sending power to the front wheels only when rear traction is at its limit. Driver controls, however, allow full control of power distribution between the front and rear axles in the M Dynamic Mode's M xDrive 4WD Sport menu. An electronically-controlled multiple clutch in the transfer case controls power output front to rear.
Both new M models get Adaptive M Suspension as standard. This electronically-controlled damper system controls body movement at each wheel through internal electromagnetic valves. Three modes for the dampers are employed, depending on drive mode setting, smoothing bumps for comfort or tightening chassis stiffness for higher performance. Variable ratio steering with electric-assist M Servotronic steering adds to that handling characteristic.
Both M variants will also have specific badging and other details to differentiate them from the standard models. Competition models will include special Competition badges as well as M-specific bracing at the front end for improved stiffness and handling on the track –namely a carbon fiber-reinforced plastic (CFRP) strut brace that runs between the shock towers in the engine compartment.
The M compound brakes feature four-piston front and single-piston rear calipers (fixed and floating, respectively) on 15.6-inch (395mm) front discs and 14.6-inch (370mm) rear discs.
The wheels are a light-alloy V-spoke design clad in performance tires. The 20-inch wheels on the vehicles are specified as 255/45 ZR20 at front and 265/45 ZR20 at the rear. Competition models have 21-inch wheels and move to 255/40 ZR21and 265/40 ZR21 tires (front, rear).
As with all BMW M Series vehicles, the X3 and X4 M models will include interior features such as BMW's head-up display, M-specific gauges and vehicle information outputs, bolstered sport seating, and Harman Kardon surround sound audio.