ENGINE · 1985-1995
S38 tuning
S38 — BMW E28/E34 M5 3.5/3.8 NA inline-6 M-engine. I6 NA DOHC 24v M-engine, 3.5 / 3.8 L, 286-340 HP stock. Cars: BMW E28 M5, E34 M5, E24 M6 (S38B35), M635CSi.
Engine specs
| Engine code | S38 |
|---|---|
| Configuration | I6 NA DOHC 24v M-engine |
| Displacement | 3.5 / 3.8 L |
| Production years | 1985-1995 |
| Stock power | 286-340 HP |
| ECU family | Bosch Motronic 1.2 / 1.3 → |
Tuning stages on S38
| Stage 1 | +10-20 HP (chipped EPROM swaps + adjustable fuel pressure) |
|---|---|
| Stage 2 | +25-40 HP (cams + headers + ITBs) |
| Stage 3 | +100+ HP (forced induction) |
Conservative real-world estimates. Actual results depend on hardware health, fuel quality, ambient temperature, and the specific calibration written.
Services available on S38
Common DTC codes on S38
Brands running S38
Workshop workflow
- Read the S38 ECU via OBD or bench using your existing flasher (KESS3, AutoTuner, MPPS, Trasdata, FRF).
- Open Softechpro V5 and drag the .bin / .ori / .hex / .s19 / .frf onto the workspace. The Bosch Motronic 1.2 variant is auto-detected.
- Pick the service tab and apply Stage 1 / 2 / 3 / DPF OFF / EGR OFF / AdBlue OFF as required.
- Save patched .bin — the outer CRC is recomputed automatically.
- Flash via your existing flasher. Adaptation reset via OEM scan tool if required.