Flow-optimised air intake.
To give the engine an instantaneous, immediate response, the air volume on the intake side of the throttle butterfly must be reduced to an absolute minimum. The problem in this case, however, is the large intake cross-section and air collector volume required by a high-performance power unit of this calibre. So to meet both of these requirements, the throttle butterflies in the intake manifolds are positioned right in front of the intake valves.
From front to rear, the entire flow of intake air in the new eight-cylinder power unit does not require the usual hot-film air mass flow meter with its obligatory sensors. Instead of determining engine load by means of such elaborate sensors, therefore, which would also create disadvantages in air guidance due to the geometry of the components involved, the V8 power unit of the new BMW M3 uses the engine control unit to perform this function. To do this, the system determines engine load under current driving conditions by taking the position of the throttle butterfly and idle adjuster, the position of the VANOS control unit, engine speed, air temperature and air pressure into account. This, in turn, gives the engineers at BMW M GmbH new freedom in the configuration and optimisation of the engine air intake process. And at the same time this management concept operates with maximum reliability.
The length and diameter of the eight intake funnels also helps to ensure an optimum charge effect in the oscillating tube. Like the single-piece, extra-large air collector, the funnels are made of a light composite material with a 30 per cent share of glass fibre. The air filter cartridge in the air collector, in turn, uses the maximum filter area possible, the air collector being supplied with air by an extra-large intake air silencer with three intake air openings.
Innovative exhaust system.
Though its design and configuration, the exhaust system also serves to optimise the cylinder charge cycle. To give the eight-cylinder power unit optimum power and torque behaviour, the focus is on keeping counter- pressure as low as possible, which is why exhaust gas flows through two chambers into the rear-end silencer.
The development engineers have likewise given their full attention to consistent lightweight engineering also in developing the exhaust. To achieve these and other targets, the dimensions of the exhaust manifold, the entire exhaust system, as well as all suspension and fastening elements were calculated by means of the CATIA CAD computer system, the 3D data obtained in the process being used consistently also in production and quality assurance. ...next page >>