BMW S38
motor vehicle engine
The BMW S38 is a straight-6 DOHC petrol engine which replaced the M88 and was produced from 1984–1995. 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 M88/3 engine. Compared to the M88/3, the S38 has a lower compression ratio (9.8:1), simplified exhaust manifold, catalytic converter, dual-row timing chain and a shorter camshaft duration. As per the M88/3, the S38 uses a DOHC valvetrain with shim-and-bucket valve actuation. Air intake is via six individual throttle bodies with intake trumpets, fed by a cast aluminum intake plenum.
Versions
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).
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This entry incorporates text from “BMW S38” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.