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DC Remapping UK
DC Remapping UK · BMW

BMW 40d
Custom Remap

Bespoke ECU calibrations for the N57 twin-turbo diesel. Unlock the full potential of your 40d safely on our V-Tech 4WD linked rolling road.

Stage 1 — 385–390 BHP Stage 2 — 400–410 BHP xHP Gearbox Tune xDrive Safe
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387
Tuned BHP
770
Tuned Nm
305
Stock BHP
628
Stock Nm
Tuning Packages

Choose Your Stage

ECU + Gearbox Tune
Stage 1
Power 385–390 BHP
Torque 770–780 Nm
Gearbox xHP Included

Custom ECU calibration + xHP gearbox software. No hardware modifications required. Suitable for standard cars in good health. Dyno verified on our V-Tech 4WD linked rolling road.

ECU + Gearbox + Hardware
Stage 2
Power 400–410 BHP
Torque 800–830 Nm
Gearbox xHP Included

Modifications required before Stage 2 calibration can be applied — see below. Significant gains over Stage 1 with the right hardware in place.

⚙️  Stage 2 — Modifications Required
Gearbox Software

xHP ZF8 Gearbox Tune

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What Is xHP?
xHP is the world-leading gearbox software for BMW ZF 8-speed automatic transmissions. It unlocks the full potential of the ZF8 by rewriting shift logic, torque limits and pressure tables that are locked down from the factory.

On the 40d — which produces considerably more torque than the ZF8's factory calibration is programmed to expect after a Stage 1 remap — xHP is essential, not optional. Without it, the gearbox will limit engine torque to protect itself, meaning you'll never see the true gains from your ECU map.

With xHP installed alongside your ECU remap, both systems work in harmony. Shift speeds increase dramatically, torque limits are raised to match the engine output, and you unlock additional driving modes including a track-optimised shift map. The result is faster, harder shifts and a driving experience that genuinely transforms the car.
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DC Remapping — #2 xHP Worldwide
DC Remapping UK holds the #2 ranking worldwide on the xHP global installer leaderboard — a testament to the volume and quality of gearbox calibrations carried out in our workshop. When it comes to ZF8 software on BMW applications, few operations in the world have more experience or more cars through the door.

Every xHP calibration is carried out on the dyno so we can verify the shift points and torque figures are correct for your specific ECU map — not a generic off-the-shelf setting.
The DC Difference

Bespoke 40d Calibrations

Unlock the full potential of your BMW with a custom ECU calibration from DC Remapping. Our team of experts specialise in creating bespoke calibrations tailored to your specific vehicle, making sure you get the best performance possible.

Our power and torque improvements are designed to stay within the safe limits of your engine, ensuring your vehicle remains reliable and safe to drive. With our Stage 1 Dyno Tuning, you can expect to see increases of up to 385–390 horsepower and 750–770 Nm of torque, all while maintaining the integrity of your engine and its components.

We understand the importance of maintaining the health of your vehicle, which is why we carry out a thorough health check before any tuning takes place. This ensures that any potential issues are addressed before we begin the tuning process.

Our team has spent thousands of hours researching and developing these engines, ensuring that our calibrations are accurate and reliable. Trust us to take your BMW to the next level.

At DC Remapping we use the state-of-the-art V-Tech 4WD Linked Dyno — specifically designed to handle the most complex and demanding systems, including xDrive. This ensures we can provide accurate, precise tuning for your vehicle, maximising its performance and efficiency.

We understand that every vehicle is unique. Our V-Tech 4WD Linked Dyno is xDrive safe, guaranteeing your vehicle is in the best hands. Our team of expert tuners is dedicated to providing the best tuning services for all our customers, ensuring you experience the full potential of your car's performance.

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xDrive — Safe With Us
BMW xDrive, Audi Quattro and Mercedes 4Matic systems cannot be safely run on a standard non-linked rolling road. Our V-Tech VT-4 is mechanically linked, meaning your 4WD system runs as intended — no risk of transfer box damage and no over-reading of torque figures.
On the Dyno

BMW 40d · Rolling Road

BMW 640d on DC Remapping UK dyno
BMW 640d — On the Dyno
BMW X5 xDrive on DC Remapping UK dyno
BMW X5 xDrive — 4WD Run
DC Remapping UK · Rolling Road Result
Stock vs DC Stage 1 Custom & xHP ST3 — Engine Power, Torque & Wheel Power
BMW 40d dyno graph — Stock vs DC Stage 1 Custom
See It In Action

BMW 40d · Dyno Run

Customer Reviews

What Our Customers Say

★★★★★

"Absolutely blown away by the results. The 40d feels like a completely different car — pulls hard from low down and the power delivery is so smooth. DC Remapping are the real deal."

James H.
BMW 640d Gran Coupé
★★★★★

"Took my X5 40d in for a Stage 1 remap. Gains were exactly as advertised and the xDrive ran perfectly on their 4WD dyno. Couldn't be happier — highly recommend."

Mark T.
BMW X5 xDrive40d
★★★★★

"Professional setup, friendly team and the numbers speak for themselves. 387bhp on a diesel! Health check before the remap gave me peace of mind too."

Craig W.
BMW 540d xDrive
★★★★★

"These lads know BMW 40d engines inside out. Custom map was spot on — MPG actually improved as well as the performance. Already booked the M Sport in."

Stuart M.
BMW 340d Touring

Ready to Unlock Your 40d?

Book your appointment today and experience the full potential of your BMW.

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