Tuning Guide — BMW E36 M52 (328i)
Tools & Prep
We tune on the factory MS41 ECU for OEM drivability and easy fault-code reading. Use a reliable K+DCan cable and MS41 Quickflash to flash. Baseline matters: fix vacuum leaks, confirm VANOS health, fresh plugs/coils, and a good battery.
Stage 1 — Stock Car
Fueling & ignition optimisation for a sharper curve.
- Expected: healthy cars sit ~200–205 hp.
- Gains: +5–10 hp peak from fueling & timing tweaks.
- Torque: +15–20 lb·ft lower down for better in-gear pull.
- Fuelling: Stock maps run lean low-rpm; richening for too long costs economy a touch but helps response.
- Good for: Clean baseline & daily drivability.
Stage 2 — Bolt-Ons
M50 intake + exhaust + custom tune.
- Expected: ~225–235 hp when mapped properly.
- M50 intake: +15–20 hp top-end; minor low-rpm trade-off if untuned.
- Exhaust: S50 headers help peak; may add a dip ~2k rpm.
- Tune: Smooths the whole curve; recovers low-end where possible.
- Good for: Value gains without opening the engine.
Camshafts
Hold power longer; stronger mid/top.
- Stock: ~228° / 9 mm lift — small for serious top-end.
- S52-style: ~252°/10.2 mm in, ~244°/9.5 mm ex — proven street setup.
- Mapping: Needs VANOS targets, fueling & ignition to match profile.
- RPM: We like ~7300 rpm on hydraulic lifters.
- Good for: NA builds wanting more top without ITBs yet.
Individual Throttle Bodies (ITBs)
Response, sound, and gains across the revs.
- Gains: Broad improvements; minimal losses when set up well.
- Cams: Supports wilder profiles & timing while keeping idle civil.
- Supporting: Valve springs & lifters help if you’re chasing revs.
- Mapping: Critical — airflow model changes with no plenum/MAF. Commonly tuned via Alpha-N on stock MS41.
- Good for: NA enthusiasts who want feel + top-end.
Stroker Builds
More capacity = more torque.
- Routes: M54B30 internals → M52B30; or Alpina/M3 cranks (3.2–3.4 L).
- Mid-range: Big +40 lb·ft-ish gains on like-for-like builds.
- Top-end: +30 hp+ with matching cams/exhaust & tune.
- Mapping: Re-scale fuel/airload; watch injector/MAF headroom.
- Good for: Street/track torque with room to grow.
Turbocharging
From safe low-boost to serious power.
- Low boost: ~7 psi on stock compression ≈ 300–340 hp, conservative timing.
- High boost: Lower compression (gasket/spacer or pistons); ~1.0 bar ≈ ~400 hp.
- Upper end: Some see 420–440 hp @ ~1.2 bar with strong setups.
- Focus: Charge temps, reliable fueling, knock control — reliability first.
- Good for: Max hp/£ with the right hardware & calibration.