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.
On the rollers, every map is developed live on our 4WD linked V-Tech dyno.
The numbers
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
The before-and-after printout every customer takes away, stock in red, tuned in blue.
What the transformation feels like
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.
Strapped down for back-to-back verification runs.
Why the xHP gearbox tune matters
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.
How it was done
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.
We use essential cookies to make this site work. With your consent we also use cookies to measure traffic and improve our marketing. See our Privacy Policy.
·
BMW & VAG specialists · Warrington
·
★ 5.0 on Google
·
247+ 5-star reviews
·
10,000+ vehicles tuned
·
14+ years experience
·
In-house 4WD dyno
·
0% finance available·Buy now, pay later with 
