BMW N46B18 Engine

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

N46B18 Specs

Manufacturer BMW Plant Hams Hall
Also called BMW N46
Production 2004-2005
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 10.2
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)
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 N46B18 engine reliability, problems and repair

Younger modification of N46 series was produced on base of N46B20 in 2004 and was used only for BMW E46 316i models. That is why production of E46 engines was stopped in 2005. The same thing is with this motor which has not turned out to be rather popular. Apart from N46B20 engine N46B18 had new crankshaft with low stroke as well as new pistons with 10.2 compression ratio. Non-DISA intake manifold was installed.
This version was produced to replace N42B18. N46 had new crankshaft and balance shafts along with new connecting rods, cylinder head cap, timing chain tensioner, new intake manifold and several other modifications.
Engine was managed by Bosch ME 9.2. control unit.
As well as 2-liter modification N46B18 has several related models which were produced alongside. They include N45B16 and N43B16.
Replacement for this 4-cylinder engine as well as other BMW gasoline motors appeared in 2011. It was 4-cylinder 1.6-liter turbocharged N13B16 engine.

BMW N46B18 disadvantages and problems

Common malfunctions of N46B18 are the same as in N46B20. HERE you can find out more about them.

BMW N46B18 engine tuning

N46B18 Chip tuning

As well as all other related4-cylinder BMW engines of N series, N46B18 was not designed for further upgrades and modifications. The only way to increase HP rate is to buy cold air intake and cat-back performance exhaust system combining them with aggressive ECU firmware which will add extra 10 HP. If you want more powerful engine you are recommended buying new BMW model.