[E90Fleet]

Originally Posted by waterborn0

Do you know the specific changes? Overhauling top to bottom is a bit vague.

N63TU differences

Engine mechanical
• New cylinder head due to use of the Turbo Valvetronic Direct Injection (TVDI) procedure
• 3rd generation Valvetronic
• New valvetrain with modified timing
• Adoption of VANOS from the N55 engine
• New cylinder head cover with adapted crankcase ventilation
• Pistons with modified piston crown geometry
• New connecting rod with even pitch and adaptation of the crankcase due to modified connecting rod shape
• Adapted crankshaft
• Chain drive with modified guide rails and an extruded chain with 142 elements.

Oil supply
• Pendulum slide cell pump with small overall width
• Eight individual oil spray nozzles for piston crown cooling.

Cooling
• Integration of the two engine control units in the low-temperature circuit and cooling over the back panel with cooling pipe
• Expansion tank under the left side wall with separate filling hopper.

Intake and exhaust emission systems
• Adaptation of the manifold for the air intake duct due to new geometry of the cylinder head cover
• Use of the hot film air mass meter 7
• Adoption of the charge air temperature and intake-manifold pressure sensor from the N20 engine
• Exhaust turbocharger with new compressor and modified wastegate valves
• Discontinuation of the blow-off valves.

Vacuum system
• Two-stage vacuum pump with new arrangement of the bolt connection
• Vacuum reservoir for the wastegate valves in the V-area of the engine.

Fuel preparation
• Use of the known high-pressure injection with injectors and high pressure pump HDP5
• Discontinuation of fuel low-pressure sensor

Engine management system
• New dual control unit concept with one control unit per bank
• Oil level sensor with an additional temperature sensor in the main oil duct behind the starter motor.