Tuning · BMW Z4 sDrive20i (G29)
Z4 sDrive20i
B48
The B48 in roadster form. Hand-calibrated from Stage 1 through to a hybrid-turbo build. Choose your package, send your build to Samuel, and get a tune that fits the way you actually drive.
Engine
B48
Stock
197 bhp · 320 Nm
Stage 3 ceiling
197 bhp
BMW Z4 sDrive20i tuning
A two-seat roadster is the lightest, most driver-focused body the B48 is fitted to, and that is the whole case for tuning the G29 Z4 sDrive20i: every gain is felt more keenly here than in any saloon. Owners rarely come to Samuel wanting a monster — they want an engine that works the G29 chassis as hard as it deserves, with the roof down and the shove arriving earlier in the rev range.
The sDrive20i leaves BMW with 197 bhp and 320 Nm. Stage 1 alone recalibrates that to 290 bhp and 480 Nm — no hardware, just software — and in a car this size that single flash is transformative. Stage 2 adds a downpipe and intake for 320 bhp and 500 Nm, at which point the mid-range torque runs ahead of a standard Z4 M40i's, carried in a lighter car.
The G29's tuning ceiling sits around 400 bhp — lower than the saloon B48s because the roadster carries a smaller cooling pack — reached with hybrid or full-frame turbo hardware and supporting fuelling. Everything is done remotely and reversibly: Samuel calibrates your file by hand, releases it to BM3, MHD or MG Flasher inside 24 hours, and the untouched factory map stays saved should the car ever need to go back.
Configurator
Build your Z4 sDrive20i 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 Z4 sDrive20i tuning, stages, hardware and what to expect from the G29 B48
The G29 Z4 sDrive20i runs the B48, BMW's 2.0-litre single-turbocharged inline-four, in the lightest body the engine appears in. From the factory, BMW set the sDrive20i at 197 bhp / 320 Nm, a software limiter between the 320i and 330i. BMW Z4 sDrive20i tuning with Samuel unlocks that headroom and exploits the roadster's weight advantage, the same Stage 2 figure that puts a 330i at 340 bhp feels considerably sharper in the G29 body.
Stage 1
290 bhp · 480 Nm
No hardware required. The MG1CS003 DME is flashed via the OBD port, boost pressure, ignition timing, fuel delivery and torque limiters all revised. BMW Z4 sDrive20i Stage 1 unlocks 290 bhp / 480 Nm from the OEM hardware (up from 197 / 320 stock), a transformative single change for a 1,500-kg roadster.
Every Z4 sDrive20i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW Z4 sDrive20i tuning done correctly accounts for the G29 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
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.
Z4 sDrive20i specs & stage targets
BMW Z4 sDrive20i tuning at a glance
- Engine
- B48 · 2.0L turbocharged inline-four
- Body styles
- G29 Roadster
- Chassis codes
- G29
- Production
- 2018–present
- Drivetrain
- Rear-wheel drive
- Gearbox
- 8-speed ZF automatic
- Stock output
- 197 bhp · 320 Nm
- Tuning ceiling
- ~400 bhp on the right hardware
| Stage | Target |
|---|---|
| Stage 1 | 290 bhp · 480 Nm |
| Stage 2 | 320 bhp · 500 Nm |
| Stage 3, Hybrid Turbo | Up to 400 bhp depending on spec |
| Stage 3, Big Turbo Kit | Up to 400 bhp depending on spec |
FAQ
Z4 sDrive20i tuning — frequently asked questions
The sDrive20i goes from 197 bhp and 320 Nm to 290 bhp and 480 Nm on standard hardware — and in a compact two-seater those numbers land harder than they would in a saloon. Throttle response sharpens, the torque arrives earlier, and the roadster finally accelerates the way its stance suggests.
Packaging. The G29 carries a smaller cooling pack than the saloons that share this engine, so the platform peaks a touch lower — around 400 bhp on a hybrid or full-frame turbo with supporting fuelling. Within that limit the calibration approach is the same, built per car around the fitted hardware.
In the mid-range, yes — at Stage 2 the four-cylinder car's 500 Nm arrives in a lighter package, and between corners that is what you feel. The six-cylinder keeps the advantage at the top end, but a tuned 20i closes far more of the gap than the price difference between the two cars ever suggested.
Just a downpipe and an intake, after which Samuel calibrates the standard turbo to 320 bhp and 500 Nm. On a roadster there is an added bonus: the downpipe brings more of the engine's voice into the cabin, which matters rather more with the roof folded away.
Completely. The original calibration is saved before anything is written, and flashing it back over the OBD port returns the DME to factory. At Stage 1 no physical parts have been touched, so once the stock file is restored there is nothing on the car to give the tune away.
Keep exploring
Keep exploring Z4 sDrive20i tuning
Other B48 models we tune: G20 320i, 330i, 330e, G22 420i, 430i, 530e.
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 Z4 sDrive20i, 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