The BMW S38 is a DOHC in-line six -cylinder petrol engine in four-valve technology with fuel injection the car manufacturer BMW and was introduced in 1988. The dual overhead camshafts are driven by a duplex chain. The mixture is supplied for each cylinder separately through its own intake manifold and throttle valve (single throttle system). He came in the E34 M5 used. The origins of the engine in the BMW M30, with which he has in common, however, is not much and is also based on the successor to the M30 BMW M88.

The special feature of the S38 is compared to other BMW six-cylinder engines in the then used only in racing single throttle valve system, which provides for a better cylinder filling and a better response. An electrically adjustable flap in the intake plenum, which causes the same effects as a variable intake manifold length, made ​​itself felt in a better power delivery in the lower speed range.

Was developed and built the engine, just like the corresponding vehicle at the BMW M GmbH.

This engine was only offered with a manual gearbox, first with a 5 - speed gearbox and from 05 / 94 to a 6 -speed transmission manufacturer Getrag.


The S38 is an evolution of derived from the M30 engine BMW M88. While the M88 had a displacement of 3.5 liters, available to the first embodiment of the S38 ( S38B36 ) through a displacement of 3.6 liters. An increase to 3.8 liters ( S38B38 ) was achieved by a larger hole and a new forged crankshaft, which raised the stroke from 86 to 90 mm. Further, the intake valves have been enlarged and the air filter housing for optimum flow. The S38B38 engine weighs 236.8 kg.



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