Another modern BMW petrol refined properly. This 2020 BMW 420i — the B48 2.0 turbo petrol — came in for our full engine and gearbox package: a custom Stage 1 dyno calibration paired with xHP gearbox tuning, all developed live on our 4WD linked V-Tech dyno.
It arrived producing 179bhp and 274Nm on our baseline run. After the Stage 1 calibration and xHP gearbox tuning, it left making 284bhp and 412Nm — measured on the rollers, not estimated:
| Measurement | Stock | DC Stage 1 + xHP |
|---|---|---|
| Engine power | 179.1 hp @ 5,721rpm | 284.0 hp @ 5,600rpm |
| Engine torque | 274 Nm @ 2,162rpm | 412 Nm @ 3,144rpm |
| Wheel power | 142.3 hp @ 4,946rpm | 243.1 hp @ 5,374rpm |
That’s +105bhp and +138Nm, and the focus here was smooth, usable performance rather than just peak numbers. The result is a completely different driving experience — sharper throttle response, a much stronger mid-range and effortless acceleration, all while keeping OEM-level refinement and reliability.
Paired with xHP gearbox tuning, the ZF8 transmission responds far more effectively to the increased power — quicker, cleaner shifts and improved torque management. The overall package feels sharper, more responsive and far more engaging to drive.
As with every vehicle we tune, all work was carried out in-house on our 4WD linked V-Tech dyno, with a full health check before any tuning and live data logging throughout. The map was written for this exact car — its ECU variant, its fuel, its condition. No generic files. No shortcuts. Just precision B48 tuning done properly, with the original software backed up so it’s fully reversible.
420i, 430i or another B48-powered BMW — we can transform how it drives. See our engine + gearbox tuning page for packages, check your car’s gains, or get a free quote and we’ll book you in.
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Specialist BMW & VAG tuning, dyno-proven in Warrington. Tell us your car and we’ll send your gains and pricing.
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