Tuning · BMW 330i (G20 / G21)
330i
B48
The B48 in everyday saloon form. Hand-calibrated from Stage 1 through to a hybrid-turbo build. The B48 is sharper than its reputation when calibrated correctly.
Engine
B48
Stock
255 bhp · 420 Nm
Stage 3 ceiling
255 bhp
BMW 330i tuning
The G20 330i arrived in 2019 as the B48-powered successor to the N20 F30, available in Saloon (G20) and Touring (G21) body styles. BMW set the factory output at 255 bhp · 420 Nm — the same block, head, and turbo as the 320i, with a fuller injector calibration but the same conservative software ceiling. The DME is either the MG1CS003 on later production cars or the MEVD17 on early examples, both accessible over OBD with no bench work required. Drivetrain on UK spec is rear-wheel drive with the 8-speed ZF automatic on every variant Samuel tunes; manual-gearbox versions exist in some markets and take the same ECU map. The 330i shares its hardware ceiling with the 430i and 530i — once the software limits are lifted, the platform behaves consistently across all three. At Stage 1, no hardware changes and OBD flash only, the B48 moves from 255 bhp to 310 bhp with torque rising from 420 Nm to 520 Nm. That's where most 330i owners start, and the margin it uncovers was already in the engine before the car left the factory.
The 330i (G20 / G21) sits at the top of the naturally aspirated B48 lineup in the 3 Series — the same hardware as the 320i below it and the same platform ceiling as the 430i and 530i it shares a family with. That cross-model consistency matters: every B48 stage target has been validated across the family, and the 330i calibration is built with the G20 chassis and ZF gearbox as the reference point. Samuel tunes the G20 Saloon and G21 Touring to an identical spec — 310 bhp · 520 Nm at Stage 1 with no hardware required, 340 bhp · 550 Nm at Stage 2 with downpipe and intake, and up to 500 bhp on a hybrid or full big-turbo build — every map built for the specific car, its fuel grade, and the hardware list submitted with the order.
Configurator
Build your 330i 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
330i tuning on the G20 / G21: B48 in context
The B48 in the 330i is the same unit fitted to the 320i, 430i, 530i, and Z4 sDrive20i — same block, same head, same turbo across the family. What varies between those chassis is weight, drivetrain, and the factory software limit. In the G20 / G21, the combination of rear-wheel drive and the 8-speed ZF means xHP gearbox calibration is worth considering from Stage 2 onwards, where torque climbs 130 Nm above the stock figure and the default transmission map wasn't built for that load. Samuel's 330i calibration accounts for the ZF — stage targets match the rest of the B48 family, and the map is built with the gearbox calibration in view.
Stage 1
310 bhp · 520 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. BMW 330i Stage 1 unlocks 310 bhp / 520 Nm from the OEM hardware (up from 255 / 420 stock), with a noticeably broader torque curve and sharper throttle response. The BMW 330i chip tuning starting point for almost every owner.
Every 330i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW 330i tuning done correctly accounts for the G20 chassis behaviour, the 8HP gearbox calibration and UK fuel quality; the map is reviewed against your data logs after the first flash and revised before sign-off.
Compatibility
This 330i tune runs on Bootmod3, MHD or MG Flasher — all three flash the B48 over OBD. Compare platforms or see full B48 compatibility.
330i specs & stage targets
BMW 330i tuning at a glance
- Engine
- B48 · 2.0L turbocharged inline-four
- Body styles
- G20 Saloon · G21 Touring
- Chassis codes
- G20 / G21
- Production
- 2019–present
- Drivetrain
- Rear-wheel drive
- Gearbox
- 8-speed ZF automatic
- Stock output
- 255 bhp · 420 Nm
- Tuning ceiling
- ~500 bhp on the right hardware
| Stage | Target |
|---|---|
| Stage 1 | 310 bhp · 520 Nm |
| Stage 2 | 340 bhp · 550 Nm |
| Stage 3, Hybrid Turbo | Up to 500 bhp depending on spec |
| Stage 3, Big Turbo Kit | Up to 500 bhp depending on spec |
FAQ
330i tuning — frequently asked questions
This page covers the G20 Saloon and G21 Touring (2019–present). Both body styles run the B48 2.0L turbocharged inline-four and take the same core ECU calibration — Samuel tunes them to an identical spec. Every 330i map is built for the specific car: fuel grade, installed hardware, and chassis variant are all submitted at order and factored into the calibration before it's delivered.
A factory warranty can be voided if BMW attributes a specific failure to the tune. Samuel's 330i maps are calibrated within the mechanical limits of the B48 hardware — the turbo, fuel system, and internals all run well within their tolerances at Stage 1 and Stage 2. The tune is fully reversible to the supplied stock file before any dealer visit; many owners run a tuned 330i without issue. It's a personal call.
The calibration Samuel delivers is the same on all three — the platform is your flashing tool, not the map. BM3 is the most widely used for the B48 family and gives you realtime monitoring via the app, which most owners find useful for verifying the tune after the first flash. MHD has a strong data-logging toolset and suits anyone who wants to dig deeper into lambda, ignition correction, and intake temperatures after each session. MG Flasher is a clean, reliable option for owners already in the MG ecosystem — full B48 support on the MG1CS003 DME, straightforward flash process.
The 330i runs the ZF 8HP automatic on UK spec. At Stage 1 the torque increase is manageable and xHP is optional — you'll notice the difference in shift speed and response, but the stock transmission map holds. From Stage 2 onwards, where torque climbs to 550 Nm, xHP is strongly recommended: the default shift strategy and torque limits weren't built for that load. Available as an add-on on this page. Manual-gearbox variants don't need it.
Yes. Once you've flashed and run the car through a few pulls, send the logs back through BM3, MHD, or MG Flasher. Samuel checks them and revises the map before sign-off. That review step is what makes the calibration hand-built rather than a file delivered and closed — the first flash is the start of the process, not the end.
Keep exploring
Keep exploring 330i tuning
Other B48 models we tune: G20 320i, 330e, G22 420i, 430i, 530e, 530i.
Engine guide
B48 tuning
Every B48 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 330i, 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