The N45 is a compact straight-4

Straight-4

The inline-four engine or straight-four engine is an internal combustion engine with all four cylinders mounted in a straight line, or plane along the crankcase. The single bank of cylinders may be oriented in either a vertical or an inclined plane with all the pistons driving a common crankshaft....

 automobile

Automobile

An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

 piston engine from BMW

BMW

Bayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...

. The series debuted with the E87 116i in 2004. The engine does not have Valvetronic

Valvetronic

The Valvetronic system is a variable valve timing system to offer continuous and precisely variable intake valve lift, from ~0 to 10 mm, and duration. It typically works in conjunction with the independent Double VANOS system that continuously varies the timing...

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Models

Engine	Displacement	Stroke/Bore	Power	Torque	Redline	Year
N45B16	1.6 L (1596 cc / 97 in³)	72 mm / 84 mm	85 kW (115 PS) @ 6000	150 N·m (110 ft·lbf) @ 4300		2004
N45B20S	2.0 L (1997 cc / 121 in³)	88 mm / 85 mm	126 kW (173 PS) @ 7000	200 N·m (147 ft·lbf) @ 4250	7300	2006

The facelift version of the N45B16 engine was introduced in 2007. This engine contains BMW's Efficient Dynamics technology and Valvetronic. From March 2007, the 116i contains the N43B20.