BMW S52B32 Engine (Design, Issues & Tuning)

✔ This article has been fact checked.

The S52B32's design heavily relies on the M52B28 engine. This engine was created especially for M-version cars in North America as opposed to the more powerful S50B32 engine used in Europe.

It is a 3,152 cc straight-6 DOHC petrol engine which produces 240hp and 325nm. The S52 is a higher performance version of the M52 produced between 1996-2000.

The BMW S52B32 engine is used in the following cars:

• 1996-1999 E36 M3 (Canada and United States only)

• 1998-2000 E36/7/8 Z3M (Canada and United States only)

Table of Contents:

• Design

• Specs

• Problems & Reliability

• Tuning

• Images

• Videos

BMW S52B32 Engine Design

The engine features an 86.4 mm diameter bore in a cast iron cylinder block (the same as the M52B28 in North America). Because of its sturdy and lightweight forged crankshaft, it can sustain greater loads.

The piston compression height was increased to 31 mm while the connecting rods' length was reduced to 135 mm. The crankshaft was lengthened to 89.6 mm and had a 3.2L displacement with a 10.5:1 compression ratio.

A modified M52 cylinder head with a Double VANOS system is used by the S52 engine. It boasts redesigned camshafts, stiffer valve springs, and larger water channels for better cooling. This engine's head gasket is distinct from that of M52 engines and cannot be used on them.

The S52B32 camshaft has a duration of 252/244 degrees and a valve lift of 10.2/10.2 mm.

In the intake system, a simple plastic intake manifold and an electronic throttle body are employed, and in the exhaust system, a new, more effective exhaust manifold is utilised. Siemens MS41.1 is used for the engine management system.

Because of their better reliability and more flexible tuning options, many European car enthusiasts purchase S52 engines from the US.

Up until 2000, this engine was installed under the hood of BMW M3 E36 or Z3M vehicles sold in the US and Canada. In 2000, the S54B32 took its place.

Engine 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

• Redline RPM: 7,000 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

The S52B32 engine does have some common issues, as detailed below.

• Leaky thermostat: The plastic thermostat's thin walls are frequently where coolant leaks develop.

• Oil usage: When pistons are subjected to heavy loads, excessive oil consumption may cause significant damage.

• Cylinder head coolant leak: The likelihood of coolant entering the cylinder if the engine overheats is increased by the bigger cooling channel in the head.

• Lambda sensor: When there are air leaks in the intake manifold, the Lambda sensor gives false readings. This happens fairly often with the S52 engine.

Tuning & Performance Upgrades

The majority of users typically default to remapping when tuning, although there are several more ways to modify your S52B32.

• Stage 1 improvements include fast road camshafts, sports exhaust manifolds, panel air filters, drilled and smoothed air boxes, intake headers, and remaps/piggyback ECUs.

• Stage 2 modifications include the induction kit, performance catalyst and performance exhaust, ported and polished heads, modified fuel pumps, and high flow fuel injectors.

• Stage 3 modifications include adding or upgrading forced induction (turbo/supercharger), twin charging conversions, engine balancing and blueprinting, internal engine upgrades (head flowing porting/bigger valves), competition cam, crank, and piston changes to adjust compression.

Intake

The geometry and flow conditions of the air intake manifolds on the S52B32 may significantly affect atomization. Despite the fact that certain manufacturers offer reasonably well-flowing air intake manifolds, the majority require motorsport parts.

Power could be increased by using larger intake pipes, smoother pipework, a cold air feed, or ram air feed.

Camshafts

One of the most important mechanical upgrades is the installation of fast road cams, but this requires a competent technician who is not always easy to find.

In most cases, these modifications won't increase power on their own, but by reducing the restriction, they could help boost power following other mods.

Forced Induction

The best method for increasing airflow is forced induction, which enables you to burn more fuel and generate more power. Even though it is one of the priciest modifications, it provides the most gains in power.

Headwork

The purpose of porting and flowing the head is to enhance airflow while reducing flow restrictions and turbulence.

Power can be increased by enlarging the S52B32 valve, adding port matching, and head flowing; as an additional benefit, you'll be able to get a bigger boost from other tuning modifications.

Mapping

Unlocking the full potential of all the parts you've installed on your S52B32 should be made easier with the help of ECU mapping.

Because the factory ECU is locked, in some instances, flashing is not an option, thus an aftermarket ECU is the preferred option. Many of them will outperform factory ECUs, but make sure it has knock protection and is installed properly.

On turbocharged vehicles, it will usually offer you around 30% more power, and on naturally aspirated engines, it will offer you around 15% more power, but the final result will depend on the parts you've installed and the condition of your engine.

Images

Below are images of the BMW S52B32 engine.

Videos

Sources