BMW S38

Source: Wikipedia, the free encyclopedia.
BMW S38 engine
DOHC
Combustion
Fuel typePetrol
Chronology
PredecessorBMW M88
SuccessorNone

The BMW S38 is a straight-6 DOHC petrol engine which replaced the M88 and was produced from 1984–1995.[1][2] The S38 was originally produced for North America as an equivalent to the M88 with slightly lower power output. In 1989, power output of the S38 was increased and it became the worldwide replacement for the M88.

In 1998, the BMW M5 switched to the S62 V8 engine. There is therefore no direct successor to the S38, however the BMW S50 engine took over as BMW's high performance straight-6 engine.

Design

The S38 is based on the

throttle bodies with intake trumpets, fed by a cast aluminum intake plenum.[6]

Versions

Version Displacement Power Torque Years
S38B35 3,453 cc (210.7 cu in) 190 kW (255 hp)
at 6,500 rpm
330 N⋅m (243 lb⋅ft)
at 4,500 rpm
1986–1989
S38B36 3,535 cc (215.7 cu in) 232 kW (311 hp)
at 6,900 rpm
360 N⋅m (266 lb⋅ft)
at 4,750 rpm
1989–1993
S38B38 3,795 cc (231.6 cu in) 250 kW (335 hp)
at 6,900 rpm
400 N⋅m (295 lb⋅ft)
at 4,750 rpm
1991–1995

S38B35

The initial version of the S38 has a bore of 93.4 mm (3.7 in) and a stroke of 84 mm (3.3 in).

Applications:

S38B36

For the S38B36, the displacement was increased to 3,535 cc (216 cu in).

engine management.

Applications:

S38B38

In late 1991, BMW further enlarged the S38 engine to 3,795 cc (231.6 cu in), by increasing the bore to 94.6 mm (3.72 in) and the stroke to 90 mm (3.54 in).[10] Power increased to 250 kW (335 hp) at 6,900 rpm and torque increased to 400 N⋅m (295 lb⋅ft) at 4,750 rpm.[7]

The engine management was upgraded to

coil-on-plug ignition. Other changes included the compression ratio increasing to 10.5:1, a dual-mass flywheels, an exhaust manifold made of Inconel, larger intake and exhaust valves, lighter pistons, and the throttle bodies increasing by 4 mm (0.16 in) to 50 mm (2.0 in).[8]

Applications:

References

  1. ^ "BMW S38B35 car engine". bmw-grouparchiv.de. Retrieved 17 June 2019.
  2. ^ "BMW S38B38 automotive engine". bmw-grouparchiv.de. Retrieved 17 June 2019.
  3. ^ a b c "BMW S38 engine". www.usautoparts.net. Archived from the original on 18 November 2012.
  4. ^ "FAQ E28 M5". www.bmwmregistry.com. Retrieved 16 September 2017.
  5. ^ "BMW S38 Valve adjustment tool". www.bigcoupe.com. Retrieved 16 September 2017.
  6. ^ "BMW M88 and S38 M-Tech 24 Valve Six Cylinder Engines". www.unixnerd.co.uk. Retrieved 14 September 2017.
  7. ^ a b c "Information on Motorsport engines". www.bmwheaven.com. Retrieved 14 September 2017.
  8. ^ a b "FAQ E34 M5". www.bmwmregistry.com. Retrieved 16 September 2017.
  9. ^ "Exhaust manifold - M5 3.6 E34 Sedan USA S38". wwwbmwfans.info. Retrieved 14 September 2017.
  10. ^ Zal, Pawel. "1994 BMW M5". Automobile-Catalog. Retrieved 2018-12-08.