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BMW M52

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BMW M52 engine

M52TUB25 from an E46 323Ci (125 kW/245 Nm)
Overview
ManufacturerBMW, Bayerische Motoren Werke AG
Production1994–2001
Body and chassis
ClassStraight-6
Chronology
PredecessorBMW M50
SuccessorBMW M54

The BMW M52 is a Straight 6 piston engine. Displacement ranges from 2000 cc to 3200 cc. It is a DOHC 24-valve engine, originally introduced with VANOS Variable Valve Timing. It replaced the BMW M50 engine in 1994 and was replaced in 2001 with the BMW M54 engine. The world market engine used Nikasil lined aluminium cylinders instead of a cast iron sleeves used in the Americas market engine. The reason for this is Nikasil is eroded by the higher sulfur content fuel used in Americas.

In markets with low-sulfur fuel this engine was very highly regarded and the M52 was on the Ward's 10 Best Engines list for 1995 through to 1998. However, there was criticism of the M52 engine in some markets, especially the UK, which had high levels of sulfur in the petrol during the late 90's. Sulfur acts as a corrosive agent against Nikasil and led to a lot of the early engines having premature bore-liner wear. Fortunately this problem was solved in post-September 1998 cars with the introduction of steel cylinder liners, with the designation M52 TU-3. However problems are still present in these engines so affected cars of this period should be bought with caution unless the service history verifies that work was carried out to rectify the problem. The American market M52 used iron sleeves from the beginning, and so, was unaffected by this problem.

A Technical Update or M52TU version in 1999 added Double-VANOS and other modifications.

Models
Engine Displacement Power Torque Redline Year Stroke Bore Compression
M52B20 2.0 L (1991 cc/121 in³) 110 kW (148 hp) @ 5900 190 N·m (140 ft·lb) @ 4200 6500 1994 66 mm (2.6 in) 80 mm (3.15 in) 11.0:1
M52TUB20 110 kW (148 hp) @ 5900 190 N·m (140 ft·lb) @ 3500 6500 1998 66 mm (2.6 in) 80 mm (3.15 in) 11.0:1
M52TUB24 2.4 L (2394 cc/146 in³) 135 kW (184 hp) @ 5800 240 N·m (177 ft·lb) @ 3600 6500 2000
M52B25 2.5 L (2494 cc/152 in³) 123 kW (170 hp) @ 5500 245 N·m (181 ft·lb) @ 3950 6500 1995
M52TUB25 123 kW (170 hp) @ 5500 245 N·m (181 ft·lb) @ 3500 6500 1998 75 mm (2.95 in) 84 mm (3.31 in) 10.5:1
M52B28 2.8 L (2793 cc/170 in³) 142 kW (193 hp) @ 5300 280 N·m (207 ft·lb) @ 3950 6500 1995 84 mm (3.31 in) 84 mm (3.31 in) 10.2:1
141 kW (191 hp) @ 5300 275 N·m (203 ft·lb) @ 3950 6500 1997
M52TUB28 142 kW (193 hp) @ 5500 280 N·m (207 ft·lb) @ 3500 6500 1998

M52B20

A 2.0 L (1991 cc/121 in³) version was introduced in 1994. Bore is 80 mm and stroke is 66 mm.

Applications:

Ogun Kaya

M52TUB20

Applications:

M52B24

2.4 L. For Thai market only.

Applications:

M52B25

A 2.5 L (2494 cc) version introduced in 1995, with an alloy block (at least for Europe). It produces 125 kW (170 hp). Bore is 84 mm and stroke is 75 mm, as for the previous M50B25Applications:

M52TUB25

While retaining most of the internal dimensions and components of the earlier M52, the M52TU (Technical Upgrade) featured an aluminum alloy block in all markets including North America. More importantly, it featured a revised head design with Double-VANOS (variable intake AND exhaust cam timing) for additional improvements in torque delivery, economy and emissions. It also featured a variable intake manifold and an upgraded Siemens engine control system.

Applications:

M52B28

A 2.8 L (2793 cc) version also debuted in 1994. It has square 84 mm bore and stroke and produces 193 hp (142 kW).

Applications:

M52TUB28

Applications:

S52B32

This engine was sold only in the USA and Canada and is closely based on the iron-block USA-spec M52 engine. It differs in having an 86.4mm bore and an 89.6mm stroke for a displacement of approximately 3.2 litres. It shares very few components with the European S50. The S52 is essentially a large displacement M52 with minor upgrades to increase performance. It uses a regular M52 head with the same stepped VANOS system (on the intake cam only) but uses more aggressive cams. The intake manifold and throttle body is from the M52B28. The exhaust manifolds are the same between M52 and S52 but the S52 uses special muffler designed by Boyesen that is less restrictive. Even the connecting rods are exactly the same 135 mm units used in the M52B28. The lubrication system on the S52 is optimized for greater flow. Engine management is handled by the same Siemens system as the M52 but is tuned to the larger displacement and slightly more performance biased.

Physically, there are very few external characteristics that distinguish the S52 from its M52 brother. The "M-Power" valve cover is the easiest to spot although it must be noted that S52 and M52 valve covers are easily interchangeable. A more subtle difference is the oil filter housing. While the M52 uses a threaded black plastic cover on its filter, the S52 uses an aluminum cover held in place by a bolt. This is the same housing as was used on the 1991-1995 M50 series engines. As such, the S52 uses M50-style filter cartridges instead of the M52 style. Power from the S52B32US is officially quoted at 240 HP but many[who?] feel that this figure is understated. Maximum permissible engine speed varies from 6500 rpm to 6800 rpm to allow a margin of safety for the hydraulic lifters and the rest of the valve-train, although the engine can safely rev to 7000 rpm.

Applications:

See also

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