Tuning · BMW M140i (F20 / F21)
M140i
B58 Gen 1
One of the great hot-hatch sleepers. Calibrated by hand 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.
Engine
B58 Gen 1
Stock
335 bhp · 500 Nm
Stage 3 ceiling
335 bhp
About this tune
The F20 / F21 M140i (2016-2019) is the LCI 1 Series hot hatch with the B58 Gen 1, the engine that replaced the N55-powered M135i. Stock is 335 bhp / 500 Nm, sent rear-wheel via the ZF 8HP. Available as the F20 5-door and the rarer F21 3-door, both sharing the identical drivetrain. Widely regarded as the last RWD 1 Series, and one of the most-tuned hot hatches in the UK, because the B58 Gen 1 underneath responds exceptionally well to a remap.
BMW M140i tuning
Few modern BMWs wear the sleeper label as honestly as the M140i. It is a five-door school-run hatch hiding a turbocharged straight-six and rear-wheel drive, a pairing BMW has never offered in a 1 Series since, and used values have made the F20 and F21 the cheapest route into this engine. Owners tune them because the drivetrain was built with far more in reserve than the factory figures suggest.
A standard M140i produces 335 bhp and 500 Nm. Samuel's Stage 1 file lifts that to 420 bhp and 600 Nm without touching a single component, and the difference in mid-range pull is immediately obvious. Fit a downpipe and an intake and Stage 2 pushes the same turbo to 450 bhp and 650 Nm; add the TU fuel pump and Stage 2+ finds 480 bhp and 680 Nm, the honest limit of the standard hardware.
Past the bolt-on stages the ceiling sits around 1,000 bhp, reached with hybrid or full-frame turbo hardware and a calibration built specifically around your parts list. None of it needs the car to visit anyone: Samuel works remotely through BM3, MHD or MG Flasher, your file is ready within 24 hours of sending your build, and the original map is saved before you flash so the hatch can return to standard at any point.
Configurator
Build your M140i 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
Engine guide
BMW M140i tuning, stages, hardware and what to expect from the F20 B58 Gen 1
The M140i runs the B58 Gen 1, BMW's 3.0-litre single-turbocharged inline-six in its first-generation calibration, shared with the M240i, 340i and 440i. From the factory, BMW left meaningful headroom in the M140i's tune to suit the warranty position and global fuel-quality variation; the turbo, fuelling and chassis are all capable of considerably more than the 335 bhp / 500 Nm stock figure suggests. BMW M140i tuning with Samuel starts with finding exactly where that headroom sits on your specific car, then building a map that extracts it reliably across the full operating range. The approach is identical for a BMW M140i F20 tuning project and the F21 three-door, same drivetrain, same calibration.
Stage 1
420 bhp · 600 Nm
No hardware required. The MG1CS003 / MEVD17 DME is flashed via the OBD port, boost pressure, ignition timing, fuel delivery and torque limiters all revised. On the M140i the result is 420 bhp and 600 Nm (up from 335 / 500 stock), with substantially more accessible torque through the mid-range and a noticeably sharper throttle. This is the BMW M140i chip tuning starting point and by far the most popular single modification on the F20 / F21 platform.
Every M140i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW M140i tuning done correctly accounts for the F20 chassis weight bias, the 8HP gearbox calibration and the realities of UK fuel quality; the map is reviewed against your data logs after the first flash and revised before sign-off.
Compatibility
Platform and hardware compatibility
Bootmod3 (BM3)
Full B58 Gen 1 support across the MEVD17 (early) and MG1CS003 (later) DMEs. OBD-port flashing, realtime monitoring via the BM3 app. The most widely used platform for B58 Gen 1 tuning.
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MHD
Full B58 Gen 1 support. Suitable for Stage 1, Stage 2 and Stage 2+. Strong data-logging toolset and active community support.
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MG Flasher
Full B58 Gen 1 support. Clean interface and reliable flash process. Common alternative to BM3 for owners who prefer the MG ecosystem.
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xHP Flashtool
Compatible with the ZF 8HP gearbox fitted to every B58 Gen 1 chassis. Gearbox calibration matched to the ECU map, strongly recommended once torque jumps at Stage 2 and above. Available as an add-on.
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ECU: MEVD17 DME on early production cars; MG1CS003 DME on later production. Both accessible via OBD for Stage 1, Stage 2 and Stage 2+; bench-flash only required for some Stage 3 hybrid setups.
M140i specs & stage targets
BMW M140i tuning at a glance
- Engine
- B58 Gen 1
- Body styles
- F20 5-door · F21 3-door
- Chassis codes
- F20 / F21
- Production
- 2011–2019
- Drivetrain
- Rear-wheel drive
- Gearbox
- 8-speed ZF automatic
- Stock output
- 335 bhp · 500 Nm
- Tuning ceiling
- ~1000 bhp on the right hardware
| Stage | Target |
|---|---|
| Stage 1 | 420 bhp · 600 Nm |
| Stage 2 | 450 bhp · 650 Nm |
| Stage 2+ | 480 bhp · 680 Nm |
| Stage 3, Hybrid Turbo | 550-1000 bhp depending on spec |
| Stage 3, Big Turbo Kit | 550-1000 bhp depending on spec |
FAQ
M140i tuning — frequently asked questions
Yes — it is the biggest single change you can make to the car. Stage 1 takes the M140i from 335 bhp and 500 Nm to 420 bhp and 600 Nm using only the factory hardware, flashed at home through BM3, MHD or MG Flasher. Most owners run it for months before deciding whether Stage 2 hardware is worth the extra.
Cars built from 2018 carry a petrol particulate filter, so the Stage 2 downpipe requirement means an OPF delete on those examples. Paired with an intake or panel filter, the standard turbo then supports 450 bhp and 650 Nm. Pre-2018 cars simply need the downpipe and intake; the calibration is matched to whichever setup your car runs.
Fuelling headroom. The B58 TU fuel pump lets the map hold more boost higher in the rev range, taking the M140i from Stage 2's 450 bhp and 650 Nm to 480 bhp and 680 Nm on the original turbo. It is the last step before turbo hardware, and for many owners the sweet spot for a fast road car.
The eight-speed ZF behind the M140i handles Stage 1 and Stage 2 torque well in normal use. Plenty of owners pair the engine map with a TCU tune for firmer, quicker shifts at higher torque levels — if yours runs one, or you plan to add one, include it when you send Samuel your build so the calibration accounts for it.
It is the lightest, cheapest body the B58 Gen 1 came in, it drives the rear wheels, and the aftermarket for the F20 platform is enormous. Because the engine is shared with the M240i, 340i and 440i, the same 1,000 bhp ceiling applies — the M140i just gets there in a smaller, more affordable package.
Keep exploring
Keep exploring M140i tuning
Other B58 Gen 1 models we tune: M240i, 340i, 440i.
Engine guide
B58 Gen 1 tuning
Every B58 Gen 1 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 M140i, 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