BMW N42B18 Engine

  1. Specifications
  2. Overview, problems
  3. Performance tuning

N42B18 Specs

Manufacturer BMW Plant Hams Hall
Also called BMW N42
Production 2001-2004
Cylinder block alloy Aluminum
Configuration Straight-4
Valvetrain DOHC
4 valves per cylinder
Piston stroke, mm (inch) 81 (3.19)
Cylinder bore, mm (inch) 84 (3.3)
Compression ratio 10.5
Displacement 1796 cc (109.6 cu in)
Power output 85 kW (116 HP) at 5,500 rpm
Torque output 175 Nm (129 lb·ft) at 3,750 rpm
Redline 6,500 rpm
HP per liter 64.6
Fuel type Gasoline
Fuel system Bosch ME 9.2
Weight, kg (lbs) 120 (265)
Fuel consumption, L/100 km (mpg)

for E46 316i
9.9 (23.8)
5.5 (42.8)

7.1 (33.1)
Turbocharger Naturally aspirated
Oil consumption , L/1000 km
(qt. per miles)
up to 0.7
(1 qt. per 850 miles)
Recommended engine oil 5W-30
Engine oil capacity, L (qt.) 4.25 (4.5)
Oil change interval, km (miles) 7,000-10,000
Normal engine operating temperature, °C (F)
Engine lifespan, km (miles)
-Official information

250+ (155)
Tuning, HP
-Max HP
-No life span loss


The engine is installed in BMW 316i E46

BMW N42B18 engine reliability, problems and repair

New 1.8-liter 4-cylinder BMW N42B18 engine was produced in 2001 to replace M43B16 and M43B18. This engine was developed on base of N42B20. The difference between N42B18 and N42B20 includes crankshaft with less stroke.
If compared with M43 engine N42B18 has new aluminum cylinder block, new connecting rods and pistons with compression ratio 10.5. At the same time new engine can boast 16V cylinder head with two camshafts. Hydraulic lifters were still used in N42.
New Double-VANOS cylinder head is installed in N42B18. At the same time new Valvetronic lifting system was also added in order to regulate the level of inlet valves. Diameter of inlet and exhaust valves is 32 and 29 mm respectively.
BMW N42B18 stock camshaft specs are as follows: duration 250/258 deg, lift 9.7/9.7 mm.
Engine is equipped with new Bosch ME 9.2 motor control unit.
This engine was used for BMW 16i models.
As well as its older version N42B18 got three successors at the same time. In 2004 N45B16 and N46B18 were produced. Last N43B16 appeared in 2007.

BMW N42B18 disadvantages and problems

BMW N42B18 minuses and pluses are the same as older N42B20 engine version has. HERE you can learn more about them.

BMW N42 engine tuning

N42B18 Chip

N42 upgrade is rather tough and demanding challenge. You will hardly find something efficient to increase HP rate available on the market. The only way to increase engine’s power is to buy cold air intake, cat back performance exhaust system and proceed with engine management tuning. Such modifications will make it possible to obtain additional ~10 HP.
More reasonable solution to this problem will be purchasing of BMW M54B30 or M54B25 and complete swap.