Cars / Vans · ECU Remapping
BMW M5 4.0i 400 hp Tuning (1995–)
Factory specification and Stage 1 remap gains for the BMW M5 4.0i 400 hp (1995–). A Stage 1 calibration adds 15 BHP and 25 Nm — software only, no hardware modifications required.
| Measure | Stock | Stage 1 | Stage 2 | E85+ |
|---|---|---|---|---|
Power BHP | 400 | 415 +15 BHP · +4% | 436 +36 BHP · +9% | 415 +15 BHP · +4% |
Torque Nm | 500 | 525 +25 Nm · +5% | 551 +51 Nm · +10% | 525 +25 Nm · +5% |
+15 BHP
Stage 1 power gain
+25 Nm
Stage 1 torque gain
Rolling road
Dyno Graph
Power (BHP, solid) and torque (Nm, dashed) across engine speed (RPM). Peak figures match our database exactly.
Hover / touch the graph
Stock: 400 bhp · 500 Nm (peak)
Stage 1: 415 bhp · 525 Nm (peak)
Stage 2: 436 bhp · 551 Nm (peak)
Tuning tool compatibility
This ECU is listed in 3 of 4 manufacturer compatibility databases.
AutoTuner
Supported
ECU: MSS52
Alientech KESS3
Supported
ECU: MSS52
Magicmotorsport FLEX
Not listed in this manufacturer's data — ask us, coverage updates frequently.
Dimsport New Genius / New Trasdata
Supported
ECU: MSS52
Existing customers upload their ECU file via the Regal Tuning File Portal. New to Regal? Request a quote first.
About this remap
BMW M5 4.0i 400 hp Stage 1 — what changes
The BMW M5 4.0i 400 hp (1995–) leaves the factory at 400 BHP and 500 Nm of torque. Manufacturers deliberately detune this engine to separate it from more expensive variants in the range — a Regal Tuning Stage 1 calibration safely recovers that headroom through the ECU alone: no hardware changes, no dyno risk, fully reversible.
Fuelling, boost pressure, ignition and torque limiters are optimised within the safe tolerances of the 4.0i 400 hp powertrain (petrol). The result is 415 BHP and 525 Nm with factory smoothness, cold-start protection and emissions behaviour retained.
Why Regal Tuning
Verified on the dyno, backed by 20+ years
Every calibration is developed and verified by Regal Tuning on an in-house 4WD dynamometer and proven across a worldwide dealer network. Your file is supplied through the Regal Tuning file portal with full technical support, and the original factory file is always kept so the vehicle can be returned to stock at any time.
Figures shown are for this exact engine variant. Gains depend on vehicle health, fuel quality and conditions — we confirm the expected output for your specific vehicle in writing before work begins.
BMW M5 4.0i 400 hp remap FAQ
How much power does Stage 1 add?
Stage 1 takes the 4.0i 400 hp to 415 BHP and 525 Nm — a gain of 15 BHP and 25 Nm over stock.
Is Stage 1 safe for this engine?
Yes — software-only calibration within the safe mechanical tolerances of the engine, gearbox and drivetrain, developed and verified on our in-house 4WD dyno.
How do I get this remap?
Request a quote with your vehicle details or registration. Existing customers upload their ECU file through the Regal Tuning file portal for a fast turnaround.
20+ years of ECU calibration
Ready to unlock your BMW M5's real performance?
Tell us your vehicle and registration — we'll confirm support and the exact expected gains for your engine before any work begins.