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S38, the Engine of the BMW M5 E34

The BMW M5 E34 stands as an icon among classic vehicles, known for its elegant design and exceptional performance. At the heart of this legendary automobile beats the impressive S38 engine, a straight-six powerhouse that unleashes an exhilarating driving experience. In this article, we will delve into detail about the engine propelling the BMW M5 E34, focusing on the S38 and its various versions.

The S38 Engine: A Marvel of Engineering

The S38, a DOHC straight-six gasoline engine, is the jewel that breathes life into the BMW M5 E34. This engine replaced the M88 and was in production from 1984 to 1995. Initially designed for the North American market, the S38 soon became the global choice, replacing the M88 in 1989.

Design and Key Features

Based on the M88/3, the S38 features notable modifications that enhance its performance. With a lower compression ratio of 9.8:1, simplified exhaust manifold, catalytic converter, dual-row timing chain, and a shorter camshaft duration, the S38 stands out for its efficiency and responsiveness.

The DOHC valve train with shim-and-bucket valve actuation, along with six individual throttle bodies fed by an aluminum intake, contributes to the distinctive power of the S38.

S38 Versions

The S38 evolved over the years, giving rise to three notable versions:

S38B35 (1986–1989)

  • Displacement: 3,453 cc
  • Power: 190 kW (255 hp) at 6,500 rpm
  • Torque: 330 N⋅m (243 lb⋅ft) at 4,500 rpm
  • Applications: E28 M5, E24 M6, E24 M635CSi

S38B36 (1989–1993)

  • Displacement: 3,535 cc
  • Power: 232 kW (311 hp) at 6,900 rpm
  • Torque: 360 N⋅m (266 lb⋅ft) at 4,750 rpm
  • Applications: E34 M5 (worldwide), E34 M5 (Canada and U.S.)

S38B38 (1991–1995)

  • Displacement: 3,795 cc
  • Power: 250 kW (335 hp) at 6,900 rpm
  • Torque: 400 N⋅m (295 lb⋅ft) at 4,750 rpm
  • Applications: E34 M5 (European specification)

In 1998, the BMW M5 underwent a significant change by adopting the S62 V8 engine, marking the end of the S38 era. Although there is no direct successor to the S38, the S50 engine became BMW’s new benchmark for high-performance straight-six engines.

FAQs: Frequently Asked Questions about the S38 Engine in the BMW M5 E34

1. What makes the S38 engine of the BMW M5 E34 special?

The S38 engine stands out for its advanced design and ability to deliver exceptional performance. With features like multipoint fuel injection, DOHC valve train, and Motronic engine management system, the S38 is a masterpiece of automotive engineering.

2. What were the key changes in the evolution of the S38 throughout its versions?

The S38 versions experienced significant improvements in terms of displacement, power, and technical features. From the S38B35 to the S38B38, each iteration elevated the engine’s performance to new levels, adopting advanced technologies to optimize efficiency and responsiveness.

3. Why did BMW decide to switch to the S62 V8 engine in 1998?

The transition to the S62 V8 engine in 1998 marked a new direction for BMW in terms of performance and technology. The decision was based on the pursuit of a more powerful and efficient engine to maintain BMW’s position in the high-performance vehicle segment. The S62 V8 met these requirements, offering an exciting driving experience.

In summary, the S38 engine is the powerful heart that drives the legend of the BMW M5 E34. With its evolution across versions, the S38 set new standards in performance and technology. Although the S62 V8 eventually took the reins, the legacy of the S38 endures as an integral part of the history of BMW sports vehicles. With its unique combination of advanced engineering and exhilarating power, the S38 engine remains a marvel admired by classic vehicle enthusiasts.