Cylinder Heads: Notes
The two N73 cylinder heads are a new development from BMW and have been adapted to the new direct injection system. The cylinder heads are equipped with Valvetronic valve gear and Bi-VANOS. The inlet camshaft and the Valvetronic eccentric shaft are jointly guided by a bridge support.
The ports for the high pressure fuel injectors are located on the intake side. The engine is equipped with a high pressure fuel pump for each cylinder head. Each cylinder head has a bucket-tappet drive on the exhaust camshaft for the high pressure fuel pump.
The secondary air ducts for subsequent exhaust gas treatment are integrated in the cylinder heads. The cylinder heads are cooled by the "cross-flow" principle. The cylinder heads are made from aluminum and are manufactured using gravity die-casting.