BMW S52B32 Engine (Specs, Reliability & Issues)

Updated: Jan 23

The M52B28 engine is largely utilised in the S52B32's design. Instead of the S50B32 engine used in Europe, this engine was designed specifically for M-version vehicles in North America.


bmw S52B32 engine

Design

The engine has a cast iron cylinder block with a diameter of 86.4 mm (the same as the M52B28 in North America). It has a forged crankshaft that is both strong and light, making it capable of handling heavier loads.


The connecting rods were cut down to 135 mm in length, while the piston compression height was raised to 31 mm. With a 10.5:1 compression ratio and a 3.2-liter displacement, the crankshaft was extended to 89.6 mm.


The S52 engine uses a modified M52 cylinder head with a Double VANOS system. For better cooling, it has revised camshafts, stiffer valve springs, and bigger water channels. The head gasket on this engine is unique and not interchangeable with M52 engines.


The duration of the S52B32 camshaft is 252/244 degrees, with a valve lift of 10.2/10.2 mm.


A simple plastic intake manifold and an electronic throttle body are used in the intake system, while a new, more efficient exhaust manifold is used in the exhaust system. The engine control unit is a Siemens MS41.1.


Several European automobile enthusiasts buy S52 engines from the United States because of their greater reliability and tuning possibilities.


This engine was found under the hood of BMW M3 E36 or Z3M cars sold in the United States and Canada until 2000. The genuine M-engine, the S54B32, replaced it in 2000.


Specs

  • Manufacturer: Munich Plant

  • Production years: 1996-2000

  • Cylinder block material: Cast Iron

  • Cylinder head material: Aluminium

  • Fuel type: Gasoline

  • Fuel system: Fuel injection

  • Configuration: Inline

  • Number of cylinders: 6

  • Valves per cylinder: 4

  • Valvetrain layout: DOHC

  • Bore: 86.4 mm

  • Stroke: 89.6 mm

  • Displacement: 3152 cc

  • Type: Four-stroke, naturally aspirated

  • Compression Ratio: 10.5:1

  • Power: 240 hp at 6,000 rpm

  • Torque: 240 lb-ft (320 Nm) at 3,800 rpm

  • Firing order: 1-5-3-6-2-4

  • Engine oil weight: 0W-30, 0W-40, 5W-30, 5W-40

  • Engine oil capacity: 5.5 litres

  • Oil change interval: 6,000 miles (10,000 km) or 12 months

  • Applications: 1996-1999 E36 M3 (Canada and USA only), 1998-2000 E36/7/8 Z3M (Canada and USA only)


Problems & Reliability

  • Leaky thermostat: The thin walls of the plastic thermostat are often the source of coolant leaks.

  • Cylinder head coolant leak: The larger cooling channel in the head increases the chance of coolant entering into the cylinder when the engine overheats.

  • Oil usage: When pistons are exposed to high loads, excessive oil consumption may cause substantial damage.

  • Lambda sensor: The Lambda sensor reads inaccurately when there are air leaks in the intake manifold. With the S52 engine, this is a rather common occurrence.


Tuning

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 S52B32.


  1. 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.

  2. Induction kit, sports catalyst & performance exhaust, ported and polished head, fuel pump modifications, and high flow fuel injectors are all common stage 2 mods.

  3. 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.


Intake

On the S52B32, 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.


Camshafts

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

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.


Headwork

Porting and flowing the head has the purpose of getting air into the engine while reducing flow constraints and turbulence.


Increasing the S52B32 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

Mapping should assist you in realising the full potential of all the components you've installed on your S52B32.


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.


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