Updated: Jan 23
The M52B20 is a two-litre six-cylinder inline engine with six cylinders. It is a member of the M52 series of engines, which also includes the M52B24, M52B25, M52B28, and S52B32.
It was first presented in 1994. The M50B20 engine, which was still in service at the time, seems to have been replaced by the new engine.
The cylinder block is made entirely of aluminium alloy, with the bore-liners being coated with Nikasil. The engine received new pistons and connecting rods (the length is 145mm). The M52B20 cylinder head, sometimes known as the M50B20TU cylinder head, is a DOHC 32-valve aluminium cylinder head.
The engine features a rudimentary plastic intake manifold and a variable timing system (VANOS) that only affects the intake camshaft. The engine uses fuel nozzles with a size of 154 cc.
After 1998, the engine was dubbed M52TUB20. Cast iron sleeves are housed inside the new aluminium cylinder block. For this engine, everything was rebuilt from the ground up, including the connecting rods, pistons, and cooling system. The Double-VANOS system, a DISA variable geometry intake manifold, and an electronic throttle body are all included in this updated version.
The M52TUB20's camshaft specs are as follows: Valve lift 9.0/9.0 mm, duration 244/228 degrees. The 2.2-liter M54B22 engine from the M54-series replaced the M52B20 in 2000.
Manufacturer: Munich Plant
Production years: 1995-2000
Cylinder block material: Aluminium
Cylinder head material: Aluminium
Fuel type: Gasoline
Fuel system: Fuel injection
Number of cylinders: 6
Valves per cylinder: 4
Valvetrain layout: DOHC
Bore: 84.0 mm
Stroke: 84.0 mm
Displacement: 2793 cc
Type of internal combustion engine: Four-stroke, naturally aspirated
Compression Ratio: 10.2:1
Power: 193 hp at 5,300 rpm, 193 hp at 5,500 rpm (TU)
Torque: 210 lb-ft (280 Nm) at 3,950 rpm, 210 lb-ft (280 Nm) at 3,500 rpm (TU)
Firing order: 1-5-3-6-2-4
Engine oil weight: SAE 0W-30, 0W-40, 5W-30, 5W-40
Engine oil capacity: 6.5 litres
Oil change interval: 6,000 miles (10,000 km) or 12 months
Applications: BMW 328i E36, BMW 328i E46, BMW 528i E39, BMW 728i E38, BMW Z3, Land Rover Defender
Problems & Reliability
This engine has no specific issues, just those that are common to the M52-series, as described below.
Overheating: Overheating is a problem with the M52B28 engine. If a cylinder head overheats, it will be destroyed.
Oil usage: The oil rings in the engine are unreliable, and when they're bad, they use a lot of oil.
Ignition: Clogged hydraulic tappets/lifters may be the source of ignition issues. The ECU will turn off the ignition for cylinders with partially closed valves.
The M52B28 has a more refined design. Its engine life is less than that of M50 engines. All M52 engines have certain faults in common.
Remapping is usually the go-to for most people when tuning, however there are a verity of paths you can go down in order to tune your M52B20.
Fast road camshafts, sports exhaust manifolds, panel air filters, drilled and smoothed air boxes, intake headers, and remaps/piggyback ECUs are all common stage 1 upgrades.
Induction kit, sports catalyst & performance exhaust, ported and polished head, fuel pump modifications, and high flow fuel injectors are all common stage 2 mods.
Twin charging conversions, engine balancing and blueprinting, internal engine enhancements (head flowing porting/bigger valves), competition cam, crank, and piston changes to adjust compression, and adding or upgrading forced induction (turbo/supercharger) are all common stage 3 mods.
On the M52B20, the form and flow parameters of the air intake manifolds may have a significant impact on fuel atomisation. Although some manufacturers supply fairly well flowing air intake manifolds, most need motorsport components.
Larger intake pipes, smoother pipework, and a cold air feed or ram air feed may help improve power.
Fast road cams are one of the most important mechanical upgrades, but they must be fitted by someone who understands what they're doing, and they're not always easy to come by.
Note that these modifications will not add power on their own in most circumstances, but they may aid boost power after other mods by eliminating the limitation.
Forced induction is the most effective way to increase air supply, enabling you to burn more fuel and produce more power. It is one of the most expensive enhancements, but it yields the greatest benefits.
Porting and flowing the head has the purpose of getting air into the engine while reducing flow constraints and turbulence.
Increasing the M52B20 valve size, adding some port matching, and head flowing will also enhance power, and as a bonus, you'll be able to receive a bigger boost from other tuning tweaks.
Mapping should assist you in realising the full potential of all the components you've installed on your M52B20.
In certain circumstances, since the factory ECU is locked, flashing is not an option, therefore an aftermarket ECU is the way to go; many of these will exceed original ECUs but be sure it has knock protection and that it is correctly installed.
It will normally offer you roughly 30% more power on turbocharged cars and around 15% more power on naturally aspirated engines, but the final outcome will depend on the items you've installed and the state of your engine.