BMW 4 Series Gran Coupe (G22) 2021> 420i 181bhp remap figures
Stock, this 2021> BMW 4 Series Gran Coupe petrol (2.0L) produces 181bhp and 300Nm. Our expected figures for a Stage 1 remap are 308bhp and 484Nm, an expected gain of up to 127bhp and 184Nm.
Choose your map
Stage 1 remap figures
A Stage 1 remap is a software-only change to the ECU on an otherwise standard car. It needs no extra parts, which makes it the usual starting point.
| Stock | Vanguard expected | Expected gain, up to | |
|---|---|---|---|
| Power | 181 bhp | 308 bhp | +127 bhp |
| Torque | 300 Nm | 484 Nm | +184 Nm |
All maps at a glance
| Map | Power | Torque | Expected gain, up to |
|---|---|---|---|
| Stock | 181 bhp | 300 Nm | |
| Stage 1Maximum software-only performance | 308 bhp | 484 Nm | +127 bhp +184 Nm |
| Stage 1 EcoPerformance with economy in mind | 276 bhp | 469 Nm | +95 bhp +169 Nm |
| Eco mapEconomy first | 266 bhp | 460 Nm | +85 bhp +160 Nm |
Who is the Stage 1 map for?
- Drivers who want a sharper throttle and a small, honest gain from software alone.
- Owners who would rather keep the car standard in every other way.
- Anyone who wants the fullest software-only map for this engine, accepting that the gain is modest without a turbocharger.
What this means for your 4 Series Gran Coupe
Without a turbocharger the improvement comes from ignition, fuelling and throttle mapping rather than boost, so expect a smaller but still noticeable change in response.
The ECU recorded for this variant is a Bosch MG1CS201. Newer ECUs often protect their software, so we read the exact unit and version on the car before confirming the figures on this page.
We remap at our Belgrave Gate workshop in Leicester, or at your home or work within 30 miles, and every job starts with a diagnostic check.
Please note: these are expected figures, not guarantees. Real results vary with the condition of the vehicle, the ECU software version, fuel quality and the hardware fitted. Some options - including Stage 2 and anything that needs extra hardware - are for off-road or competition use only. We check every vehicle first and confirm what is achievable before any work starts.
Figures reviewed 22 October 2026.
Stage 1 questions
How much power does the Stage 1 map give the BMW 4 Series Gran Coupe 420i 181bhp?
We expect 308bhp and 484Nm against 181bhp and 300Nm as standard: up to +127bhp and +184Nm. These are expected figures, and we confirm what is achievable on your own car after a diagnostic check.
Does a Stage 1 remap need any extra parts on the BMW 4 Series Gran Coupe 420i 181bhp?
No. Stage 1 is a software-only change to the ECU on an otherwise standard car.
Is there a gentler map than Stage 1 for this engine?
Yes, two. Stage 1 Eco is performance with economy in mind: 276bhp and 469Nm expected. The Eco map is economy first: 266bhp and 460Nm. Both still sit above the standard 181bhp and 300Nm.
Do I need to tell my insurer about a remap?
Yes. A remap is a modification, so you should declare it to your insurer.
More BMW 4 Series Gran Coupe figures
Other petrol variants
All petrol 4 Series Gran Coupe (G22) variants · 4 Series Gran Coupe (G22) 2021> overview · All BMW figures