Tuning · BMW 320i (G20 / G21)
G20 320i
B48
The entry-point B48 in saloon and Touring form. Hand-calibrated from Stage 1 to Stage 3. Choose your package, send your build to Samuel, and get a tune that fits the way you actually drive.
Engine
B48
Stock
184 bhp · 300 Nm
Stage 3 ceiling
184 bhp
BMW 320i tuning
The BMW 320i (G20 / G21, 2019–present) runs the B48 2.0L turbocharged inline-four and leaves the factory at 184 bhp · 300 Nm, Rear-wheel drive, 8-speed ZF automatic. Samuel tunes the G20 Saloon and G21 Touring to the same standard — every map hand-calibrated for the specific car, its fuel grade and its installed hardware, not a base file loaded and left. G20 320i Stage 1 alone takes it from 184 bhp · 300 Nm to 280 bhp · 450 Nm on the standard turbo, flashed over OBD on BM3, MHD or MG Flasher.
Add the Stage 2 hardware and the G20 320i targets 320 bhp · 500 Nm; from there the B48 stretches to around 500 bhp on a hybrid or big-turbo build with supporting fuelling. Whichever stage suits the G20 320i, the file is delivered within 24 hours and is fully reversible to the supplied stock calibration.
Configurator
Build your G20 320i 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 320i tuning, stages, hardware and what to expect from the G20 B48
The G20 320i runs the B48, BMW's 2.0-litre single-turbocharged inline-four in its detuned 184 bhp configuration. The block, head and turbo are identical to the 330i's; only the software calibration and a slightly smaller injector spec separate the two. BMW 320i tuning with Samuel exploits the fact that the 320i ships from the factory with the most conservative software limiter in the modern B48 family, there is significant headroom in the OEM hardware, and Stage 1 alone unlocks more torque than a stock 330i makes. BMW 320i G20 tuning and BMW 320i G21 Touring tuning use the same map; only the build sheet differs for the wagon exhaust geometry.
Stage 1
280 bhp · 450 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 320i Stage 1 unlocks 280 bhp / 450 Nm from the OEM hardware (up from 184 / 300 stock), one of the largest single-software gains available on any modern BMW because the factory limiter is so conservative.
Every 320i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW 320i tuning done correctly accounts for the G20 chassis weight bias, 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
Platform and hardware compatibility
Bootmod3 (BM3)
Full B48 support across every chassis in the family (320i, 330i, 420i, 430i, 530i, Z4 sDrive20i). OBD-port flashing on the MEVD17 (early) and MG1CS003 (later) DMEs. Realtime monitoring via the BM3 app, the most widely used platform for B48 tuning.
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MHD
Full B48 support. Suitable for Stage 1 and Stage 2 across the family. Strong data-logging toolset for verifying lambda, ignition correction and intake temperatures after each flash.
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MG Flasher
Full B48 support. Clean interface and reliable flash process on the MG1CS003 DME, a common choice for owners who prefer the MG ecosystem.
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xHP Flashtool
Compatible with the ZF 8HP gearbox fitted to every modern B48 chassis (G20 / G22 / G30 / G29). Available as an add-on, strongly recommended at Stage 2 where torque jumps significantly for a 2.0-litre four. Manual-gearbox cars do not need xHP.
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ECU: MEVD17 / MG1CS003 DME across B48 production. Accessible via the OBD port, no bench flash required for Stage 1 or Stage 2.
G20 320i specs & stage targets
BMW 320i 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
- 184 bhp · 300 Nm
- Tuning ceiling
- ~500 bhp on the right hardware
| Stage | Target |
|---|---|
| Stage 1 | 280 bhp · 450 Nm |
| Stage 2 | 320 bhp · 500 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
G20 320i tuning — frequently asked questions
G20 320i Stage 1 lifts the B48 from a stock 184 bhp · 300 Nm to 280 bhp · 450 Nm, with no hardware required. The map is flashed through the OBD port on BM3, MHD or MG Flasher and is the starting point for almost every G20 320i owner — broader torque and sharper throttle response from the factory hardware.
This page covers the G20 Saloon and G21 Touring (G20 / G21). They share the B48 2.0L turbocharged inline-four and run the same core calibration, but every G20 320i tune Samuel delivers is tailored to your exact car, fuel grade and installed hardware — never a base map loaded and left.
Stage 2 on the G20 320i targets 320 bhp · 500 Nm and needs downpipe + intake. Everything else — turbo, fuel system, intercooler — holds within the Stage 2 figures on the B48.
On the right hardware spec the B48 in the G20 320i reaches around 500 bhp. Stage 1 and Stage 2 run the standard turbo; beyond that needs a hybrid or full big-turbo conversion with supporting fuelling, and the calibration is built bespoke per car.
Remotely. Once Samuel has your build details, the calibrated G20 320i map is delivered to your flashing tool account (BM3, MHD or MG Flasher) within 24 hours and you flash it yourself over OBD in about 15 minutes. It's fully reversible — the original B48 stock file is supplied before you flash, so the car can return to factory at any time.
A factory warranty can be voided if BMW shows a tune caused a specific failure, so it's a personal call. Samuel's G20 320i maps are calibrated to stay within the mechanical limits of the B48 hardware, and because the tune is reversible to stock before any dealer visit, many owners run a tuned G20 320i without issue.
Keep exploring
Keep exploring G20 320i tuning
Other B48 models we tune: 330i, 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 G20 320i, 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