Custom Dyno Tuning & xHP Gearbox Tuning – tailored for your BMW 40D G-series

BMW B57 40D Engine Tuning
 

BMW G-Series 40d Stage 1 Custom Dyno Tuning

The BMW G-Series 40d represents the next evolution of BMW’s renowned 3.0-litre straight-six diesel platform. Refined, immensely powerful, and exceptionally smooth, the 40d combines modern ECU strategy with BMW’s latest drivetrain technology to deliver effortless real-world performance.

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Powered by the latest iteration of the B57 engine and paired with the ZF 8-speed automatic transmission, the G-Series 40d offers outstanding torque delivery and everyday usability. Most models are equipped with BMW’s xDrive all-wheel-drive system, ensuring the substantial torque output is transferred cleanly and consistently to the road in all conditions.

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The 40d engine is found across a wide range of BMW G-Series models, including:

• BMW X3 M40d (G01)

• BMW X4 M40d (G02)

• BMW X5 40d (G05)

• BMW X6 40d (G06)

• BMW 540d xDrive (G30/G31)

• BMW 740d xDrive (G11/G12)

• BMW 840d xDrive (G14/G15/G16)
   

In factory form, BMW typically quote figures of around 340bhp and 700Nm. However, on our 4WD linked dyno, we regularly see stock outputs closer to 320–330bhp and 670–690Nm, leaving considerable headroom within the OEM calibration.

With our Stage 1 custom dyno ECU tuning, the BMW 40d truly comes alive.

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We consistently achieve circa 395–405bhp and 780–820Nm of torque, transforming the vehicle’s acceleration and in-gear performance while retaining smooth, refined power delivery. Throttle response is sharpened, mid-range torque is significantly increased, and overtaking performance is dramatically improved — all without sacrificing drivability or comfort.

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Our calibrations are torque-managed, gear-aware, and safety-led, ensuring power is delivered progressively and sympathetically to the drivetrain. This approach keeps gearbox operation smooth, protects driveline components, and results in a car that feels fast everywhere, not just at full throttle.

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Having tuned hundreds of BMW 40d and 35d platforms, our extensive R&D allows us to extract industry-leading gains while maintaining OEM-level reliability. Every Stage 1 calibration is developed in-house on our dyno and tailored specifically to the vehicle in front of us — no generic files and no compromises.

The end result is a G-Series 40d capable of super-saloon performance, with effortless torque, refined delivery, and long-term reliability you can trust.

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​xHP Gearbox Tuning (ZF8 Transmission)

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The ZF8 automatic gearbox in the BMW 40D G-series is exceptionally strong and, when optimised through xHP gearbox tuning, it transforms how the car drives.

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xHP Stage 1, Stage 2, and Stage 3 gearbox software enhances:

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• Shift speed and smoothness

• Gear display in all modes

• Torque limit removal

• Improved launch control

• Smarter shift points for performance and comfort
   

The ZF8 gearbox is capable of handling up to 950Nm of torque with ease, making it the perfect pairing for our custom Stage 1 and Stage 2 engine tuning.

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Dyno Tuning & Safety

All BMW xDrive vehicles are tuned on our mechanically linked 4WD rolling road, which is fully xDrive safe.

Unlike non-linked dynos — which can damage the transfer box or give false torque readings — our dyno provides accurate, real-world performance data.

Before any tuning, your vehicle undergoes:

• Full diagnostics and live data checks

• Health assessment and DPF regeneration

• Custom data logging to ensure optimal safety and results
   

At DC Remapping UK, every tune is designed for maximum performance, reliability, and drivability giving you the ultimate BMW diesel tuning experience.