BMW M3 Convertible

The move to eight cylinders in the fourth generation BMW M3 provides a powerplant offering the seemingly disparate characteristics of more power, increased efficiency and reduced weight when compared with the previous six-cylinder M3 engine. Displacing 3,999 cubic centimeters (4.0 liters), the new light-alloy engine produces 414 hp at 8,300 rpm and 295 pounds-feet of torque at 3,900 rpm with 85 percent of the maximum torque available consistently through 6,500 rpm. This power output represents a 24 percent increase over the six-cylinder from the last generation M3 and it comes with a seven percent weight saving. Compression ratio is dialed in to 12.0:1 and redline is set at 8,400 rpm.The V8 engine of the new BMW M3 Convertible boasts the company's variable double-VANOS camshaft management. Offering extremely fast and responsive valve timing, this technology reduces charge cycle losses and improves the output, torque and response of the engine, with a positive influence on fuel economy and emission management.A separate throttle butterfly for each cylinder - eight in this instance - is a feature adapted from BMW M's racing heritage and provides immediate reaction to the gas pedal at all times. Two stepper motors operate the four throttle butterflies on each row of cylinders, giving the engine a particularly sensitive response at low speeds together with an immediate reaction whenever the driver presses down the accelerator for extra power and performance.A volume flow-controlled, pendulum-slide cell pump supplies the engine with lubricating oil, delivering the quantity required by the engine. Wet sump oil lubrication, optimized for dynamic performance, ensures consistent oil supply to the high-rpm engine at all times, particularly in extreme braking maneuvers. The system features two oil sumps-a small oil sump in front of the front axle subframe and a large oil sump behind it.A new, comprehensive electronic management system coordinates all engine functions with optimum efficiency and maximizes operational integration with the clutch, gearbox, steering and brakes. In addition, the engine control unit performs a wide range of on-board diagnosis functions and masterminds the ancillary engine units.A highlight of the engine management system is the use of ion-current technology to determine engine knock as well as misfire and poor combustion events within the cylinders. Contrary to conventional methods, this monitoring and control function is performed precisely where the phenomena occurs-within the combustion chambers. The spark plug in each cylinder senses and controls the risk of knocking, at the same time monitoring the correct ignition and recognizing any misfiring. In other words, the spark plug acts as an actuator for the ignition and as a sensor monitoring the combustion process, and is therefore able to distinguish between a misfire and poor combustion. This dual function of the spark plugs facilitates the diagnostic procedures required in service and maintenance.