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 Saloon / G21 Touring, 2019–present) leaves the factory at 184 bhp · 300 Nm. Stage 1 takes that to 280 bhp · 450 Nm with no hardware changes — Samuel calibrates the MG1CS003 / MEVD17 DME via OBD on BM3, MHD or MG Flasher, every file built for the specific car and its fuel grade. Stage 2 adds downpipe and intake and targets 320 bhp · 500 Nm; the B48 runs to around 500 bhp on a hybrid or big-turbo build with supporting fuelling.
The G20 320i is the most conservatively mapped B48 in the current 3 Series range. The block, turbo, and fuel system it shares with the 330i are the same physical hardware — only the software calibration limits it to 184 bhp. That gap is large enough that Stage 1 alone gives the 320i more torque than a stock 330i makes. G20 Saloon and G21 Touring run the same core calibration; the only variable between them is the build sheet you submit.
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
This G20 320i tune runs on Bootmod3, MHD or MG Flasher — all three flash the B48 over OBD. Compare platforms or see full B48 compatibility.
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 goes from 184 bhp · 300 Nm to 280 bhp · 450 Nm — no hardware required. The MG1CS003 / MEVD17 DME is flashed through the OBD port on BM3, MHD or MG Flasher. Torque band broadens noticeably across the mid-range; throttle response is sharper from lower revs.
Stage 2 targets 320 bhp · 500 Nm and requires downpipe and intake. The stock turbo and fuel system hold within those figures — nothing else needs replacing to reach Stage 2 on the B48.
Remotely, within 24 hours of payment. The calibrated file goes to your BM3, MHD or MG Flasher account; you flash it yourself over OBD in around 15 minutes. Samuel personally calibrates every file — no automated delivery.
Yes. The original stock file is supplied before you flash, so the car returns to factory calibration at any time.
The 320i runs the ZF 8HP, which responds well to xHP calibration once torque increases. At Stage 2 — where the torque jump is significant for a 2.0-litre four — xHP is strongly recommended. At Stage 1 it's optional, but the shift behaviour difference is noticeable. Available as an add-on on this page.
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