Tuning · BMW X3 M40i (G01 / G45)
X3 M40i
B58 Gen 2
The performance X3 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 X3 M40i tuning
The B58 Gen 2 in the G01 / G45 X3 M40i is the same 3.0-litre single-turbo straight-six fitted to the M340i, M440i, M240i G42, Z4 M40i and Toyota Supra 3.0 — same MG1CS003 DME, same hardware ceiling, taller and heavier SUV body. BM3, MHD and MG Flasher all have full B58 Gen 2 support on the X3 M40i. Stage 1 targets 440 bhp / 680 Nm from OEM hardware; Stage 2 adds downpipe (OPF delete if applicable) and intake for 480 bhp / 700 Nm. The X3's higher kerb weight means the torque lands with more body effect than in the M340i, but the calibration is the same. Every map hand-calibrated for the specific car and chassis variant — G01 LCI or G45 post-2024.
Engine
B58 Gen 2
Stock
374 bhp · 500 Nm
Stage 3 ceiling
374 bhp
Configurator
Build your X3 M40i 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 X3 M40i runs the B58 Gen 2 in G01 LCI (2017–2024) and G45 (2024–present) SUV form — xDrive standard, 8-speed ZF automatic. The same drivetrain as the M340i saloon in a taller, heavier body. Samuel calibrates both G01 LCI and G45 variants to the same standard; the ECU and engine are identical between the two. xHP gearbox calibration is available as an add-on and is strongly recommended at Stage 2 and above where the torque increase to 700 Nm is most pronounced on the ZF 8HP.
Compatibility
This X3 M40i 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 X3 M40i map revision covers: B58 Gen 2 stages explained
The MG1CS003 DME in the X3 M40i supports the same flash path and hardware ceiling as every other B58 Gen 2 in the lineup. BM3 and MHD both give good visibility on the platform — important at Stage 2 where torque sits at 700 Nm. Stage 1 targets 440 bhp / 680 Nm on OEM hardware — 66 bhp / 180 Nm from no hardware changes. Stage 2 adds downpipe (OPF delete if applicable) and intake for 480 bhp / 700 Nm. The TU fuel pump is factory-fitted on all B58 Gen 2 cars, so Stage 2 headroom is available without an additional pump upgrade. Every map 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 X3 M40i Stage 1 unlocks 440 bhp and 680 Nm from the OEM hardware (up from 374 / 500 stock). The BMW X3 M40i G01 tuning starting point, the most cost-effective change you can make to the SUV, and the difference is immediately obvious given the X3's weight.
Every X3 M40i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW X3 M40i tuning done correctly accounts for the SUV chassis weight, xDrive calibration and UK fuel quality; the map is reviewed against your data logs after the first flash and revised before sign-off.
X3 M40i specs & stage targets
BMW X3 M40i tuning at a glance
- Engine
- B58 Gen 2
- Body styles
- G01 SUV (LCI) · G45 SUV (post-2024)
- Chassis codes
- G01 / G45
- Production
- 2017–2024
- 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
X3 M40i tuning — frequently asked questions
Stage 1 on the X3 M40i (G01/G45) targets 440 bhp / 680 Nm from the 374 bhp / 500 Nm factory baseline — 66 bhp / 180 Nm gained from the OEM B58 Gen 2 hardware. The MG1CS003 DME is flashed via the OBD port on BM3, MHD or MG Flasher in around 15 minutes.
This page covers the G01 SUV LCI (2017–2024) and G45 SUV (2024–present) — B58 Gen 2 engine, xDrive, ZF 8HP automatic. Every tune Samuel delivers is calibrated for the specific car, its fuel grade and installed hardware.
A factory warranty can be voided if BMW attributes a specific failure to the tune — that is a personal call. Samuel's X3 M40i 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 X3 M40i without issue.
BM3 is the most widely used on the B58 Gen 2 platform and the best pick if you want realtime monitoring through the app. MHD covers Stage 1 and Stage 2 with a strong data-logging toolset. MG Flasher is the clean alternative. The calibration is the same on all three.
Yes. Once you've driven the X3 M40i on the new map, send your data logs back through your platform and Samuel reviews them before sign-off. The B58 Gen 2 in the X3 M40i operates in a heavier chassis than in the M340i — that context is part of the review before any file is signed off.
Keep exploring
Keep exploring X3 M40i tuning
Other B58 Gen 2 models we tune: M240i, M340i, M440i, Z4 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 X3 M40i, 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