Tuning · BMW M240i (G42)
M240i
B58 Gen 2
The G42 generation M240i with the Gen 2 B58 underneath. Hand-calibrated from Stage 1 to a fully bespoke big-turbo build. Choose your package, send your build to Samuel, and get a tune that fits the way you actually drive.
BMW M240i (G42) tuning
The B58 Gen 2 in the G42 M240i is the same revised 3.0-litre single-turbo straight-six fitted to the M340i, M440i, Z4 M40i and Supra 3.0 — MG1CS003 DME, ZF 8HP, the TU fuel pump fitted from factory. Samuel starts with the specific car: its fuel grade, installed hardware, and the 374 bhp / 500 Nm factory baseline. Stage 1 revises boost, ignition timing, fuel delivery and torque limits for 440 bhp / 680 Nm from the OEM hardware, flashed in around 15 minutes via the OBD port. Stage 2 recalibrates around downpipe (OPF delete if applicable) and intake, targeting 480 bhp / 700 Nm. Stage 3 is bespoke around the hybrid or big-turbo spec you submit.
Engine
B58 Gen 2
Stock
374 bhp · 500 Nm
Stage 3 ceiling
374 bhp
Configurator
Build your M240i tune
Choose your stage — Stage 1, Stage 2 or Stage 3 — add the options that fit your car, and send the full build to Samuel for a custom remote remap. He'll quote, schedule, and personally calibrate within 24 hours of confirmation.
Add a stage or add-on
£0
About this tune
The G42 M240i (2021–present) is the second-generation 2 Series coupe, the first to run the B58 Gen 2 in the smallest available body. Stock is 374 bhp / 500 Nm, xDrive, ZF 8HP — the quickest stock figures BMW have ever shipped in a 2 Series coupe. The G42 is structurally a smaller cousin of the M340i, sharing the same engine, gearbox and MG1CS003 ECU in a tighter shell. Samuel tunes the G42 coupe with xHP gearbox calibration available as an add-on, and the TU fuel pump fitted from factory means Stage 2+ hardware requirements are simpler than on the older F22 M240i.
Compatibility
This M240i tune runs on Bootmod3, MHD or MG Flasher — all three flash the B58 Gen 2 over OBD. Compare platforms or see full B58 Gen 2 compatibility.
Engine guide
What the M240i G42 map revision covers: B58 Gen 2 stages explained
The MG1CS003 DME in the G42 M240i manages boost pressure, ignition timing, fuel delivery and torque limits — and the factory calibration runs them conservatively against global fuel variation. Samuel's Stage 1 map revises each of those targets for 440 bhp / 680 Nm from the OEM hardware, flashed via the OBD port. Stage 2 recalibrates around the expanded airflow from downpipe (OPF delete if applicable) and intake, targeting 480 bhp / 700 Nm. The TU fuel pump is fitted from factory on the G42, which means the Stage 2 headroom is available without the additional fuel-pump upgrade required on older Gen 1 cars. Every file is log-reviewed after the first flash before sign-off.
Stage 1
440 bhp · 680 Nm
No hardware required. The MG1CS003 DME is flashed via the OBD port. BMW M240i G42 Stage 1 unlocks 440 bhp and 680 Nm from the OEM hardware (up from 374 / 500 stock), with substantially more accessible torque and noticeably sharper throttle. The BMW M240i G42 chip tuning starting point, the most cost-effective change available on the platform.
Every G42 M240i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW M240i G42 tuning done correctly accounts for the chassis weight, 8HP gearbox calibration and UK fuel quality; the map is reviewed against your data logs after the first flash and revised before sign-off.
M240i specs & stage targets
BMW M240i (G42) tuning at a glance
- Engine
- B58 Gen 2
- Body styles
- G42 Coupe
- Chassis codes
- G42
- Production
- 2021–present
- Drivetrain
- xDrive
- Gearbox
- 8-speed ZF automatic
- Stock output
- 374 bhp · 500 Nm
- Tuning ceiling
- ~1000 bhp on the right hardware
| Stage | Target |
|---|---|
| Stage 1 | 440 bhp · 680 Nm |
| Stage 2 | 480 bhp · 700 Nm |
| Stage 3, Hybrid Turbo | 550-1000 bhp depending on spec |
| Stage 3, Big Turbo Kit | 550-1000 bhp depending on spec |
FAQ
M240i tuning — frequently asked questions
The calibrated M240i G42 map is delivered to your BM3, MHD or MG Flasher account within 24 hours of payment confirmation. You flash it over OBD yourself in around 15 minutes — Samuel personally calibrates every file, no automated delivery.
Yes — the original B58 Gen 2 stock file is supplied before you flash, so the car can return to factory calibration at any time. The flash takes the same 15 minutes in reverse.
A factory warranty can be voided if BMW attributes a specific failure to the tune — that is a personal call. Samuel's M240i G42 maps are calibrated to stay within the mechanical limits of the B58 Gen 2 hardware, and the tune is fully reversible to stock before any dealer visit. Many owners run a tuned G42 without issue.
BM3 is the most widely used on the B58 Gen 2 and the best pick if you want realtime monitoring through the app. MHD covers Stage 1 and Stage 2 cleanly on the G42 with a strong data-logging toolset. MG Flasher is a clean alternative for owners already in that ecosystem. The calibration Samuel delivers is the same on all three.
Yes. Once you've driven the G42 on the new map, send your data logs back through your platform and Samuel reviews them before sign-off. If anything needs adjusting, the file is revised — that review step is what separates this from a generic off-the-shelf map.
Keep exploring
Keep exploring M240i tuning
Other B58 Gen 2 models we tune: M340i, M440i, Z4 M40i, X3 M40i, X4 M40i, Supra 3.0.
Engine guide
B58 Gen 2 tuning
Every B58 Gen 2 BMW we calibrate, with the full Stage 1, 2 and 3 breakdown for the engine.
Learn moreStages
Stage 1 & Stage 2 explained
What separates Stage 1 from Stage 2 on the M240i, the real-world gains and the hardware each one needs.
Learn morePricing
How tuning is priced
How the licence, off-the-shelf maps and custom calibration are priced. We quote your exact spec, never a fixed menu.
Learn moreGuide
What is bootmod3?
New to remote flashing? A plain-English explainer on the platform and how a custom map reaches your car.
Learn more