BMW X5 G05 on the DC Remapping UK 4WD dyno

ECU Calibration · Stage 1

BMW 40d Stage 1 Remap

G-Series B57 · 3.0 Straight-Six DieselCustom dyno ECU tuning for the BMW G-Series 40D. Significant gains in power and torque across the entire rev range, tailored specifically to your vehicle on our 4WD linked rolling road.

+75hpPower increase · 325 to 400 HP

+120NmTorque increase · 680 to 800 Nm

£449Stage 1

Book Your Appointment See the dyno results

4WD linked dyno, xDrive-safe
S1 · No hardware mods
In-house ECU unlocking
xHP Gold dealer
Tuning BMWs for 15+ years

About This Tune

B57 Platform. Exceptional Results.

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.

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 to 330bhp and 670 to 690Nm, leaving considerable headroom within the OEM calibration.

With our Stage 1 custom dyno ECU tuning, we consistently achieve 395 to 405bhp and 780 to 820Nm of torque. Throttle response is sharpened, mid-range torque is significantly increased and overtaking performance is dramatically improved, all without sacrificing drivability or comfort.

Our calibrations are torque-managed, gear-aware and safety led, ensuring power is delivered progressively and sympathetically to the drivetrain. Having tuned hundreds of BMW 40D and 35D platforms, our R&D allows us to extract industry-leading gains while maintaining OEM-level reliability. Every calibration is developed in-house on our dyno and tailored specifically to the vehicle in front of us. No generic files and no compromises.

+75hpPower Increase · 325 to 400 HP

+120NmTorque Increase · 680 to 800 Nm

320hpBMW Claimed 340hp · 20hp short from factory

S1Stage Level · No Hardware Mods

Compatible Models

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)

Locked ECU? No Problem

G-Series 40d? Built 2020 To Mid-2026.

If your 40d was built from June 2020, its ECU is almost certainly locked. BMW encrypt it at the factory, and it is why some places turn these cars away. We don't. We unlock it here on our own bench, on the same visit, then map it on the dyno like any other 40d.

Built	ECU	What it means
Built before June 2020	Usually not locked	Straight on the dyno, no unlock needed.
June 2020 to May 2026	Locked, we unlock it	Done in-house on the same visit. Adds £100 to your tune and no extra time.
Built from June 2026	Not yet	A new ECU lock that can't be opened yet, so we can't tune these for now.

Check If Yours Is Locked How the BMW unlock works ›

Live Dyno Data

The Numbers Don't Lie.

BMW G-Series 40D Dyno Chart — Stock vs Stage 1

Measurement	Stock	DC Stage 1
Engine Power	320-330 HP	395-405 HP +75hp
Engine Torque	670-690 Nm	780-820 Nm +120nm

Power325400bhp+75 bhp · +23%

Torque680800Nm+120 Nm · +18%

BMW Claimed vs Actual Stock: 340 to 325 HP. Tested at DC Performance Centre, Warrington. BMW's claimed factory output is 340bhp. Our stock baseline on this platform consistently measures 320 to 330bhp.

Customer Reviews

What Our Customers Say.

What BMW owners say on Google

4.9 from 269+ Google reviews

★★★★★

Had my X3 M40D and gearbox remapped at DC, and what a difference it's made, 405bhp and 811Nm end result, very professional and informative

Jamie Foster · BMW X3 M40d · Google review

★★★★★

Brilliant Place DC Remapping UK 👌 Recommended 100% 👌👍 BMW 740d stage 1 plus xhp stage 3 😊 Thank you 🙏

Adrian Rudzikiewicz · BMW 740d · Google review

★★★★★

Amazing results on my Bmw 335d F30 achieving 388hp and 771nm stage 1 with the XHP stage 3 on the ZF8 , great customer service, travelled 5hrs round trip i would definitely recommend, tranformed the car enormously.

Jon copland · BMW 335d F30 · Google review

Quoted word for word from our Google reviews. Read them all on Google.

Gearbox Software

xHP Flash.

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

From the factory the gearbox is programmed to prioritise comfort and fuel economy. xHP software unlocks its full potential, with sharper and faster shifts that better match the increased torque output from your Stage 1 tune. The ZF8 is capable of handling up to 950Nm of torque, making it the perfect pairing for our engine calibration.

The result is a car that feels substantially more alive. Power gets to the wheels quicker, the gearbox holds gears when you want it to and the overall driving experience is transformed across all conditions.

Faster, Sharper ShiftsDramatically reduced shift times across all modes. Sport and manual become genuinely responsive.
Torque Limit RemovalFactory TCU torque limiters are raised to correctly handle the elevated output of your Stage 1 tune.
Improved Launch ControlSmarter launch control function for maximum acceleration from a standstill.
Smarter Shift PointsOptimised shift points for both performance and comfort across Stage 1, Stage 2 and Stage 3 profiles.
Fully ReversibleCan be restored to factory settings at any time. Your gearbox ECU is not permanently altered.

Watch It Run

On the Dyno.

Watch a BMW G-Series 40D run on our V-tech 4WD Linked Dyno. Our dyno is fully xDrive safe, using mechanically linked axles to protect your transfer box and give accurate, repeatable results every time.

How It Works

The Process.

Full Diagnostics

Full diagnostics, live data checks and a health assessment including DPF regeneration status. Any issues are resolved before we begin tuning.

Baseline Run

Your 40D is strapped to our mechanically linked 4WD dyno for a baseline power run. We capture exact stock figures before any changes are made.

Custom Calibration

Our technicians write and apply a bespoke calibration developed specifically for the B57 engine platform. No generic files, ever.

Power Run & Verify

We run the car again to verify results and fine-tune if needed. You receive a full before and after dyno printout to take away with you.

Our Equipment

V-Tech 4WD Linked Dyno.

We use the V-tech 4WD Linked Dyno, one of the most advanced rolling road systems available. Crucially it is xDrive safe, meaning BMW's all-wheel drive system is fully protected throughout the entire testing process.

Unlike non-linked dynos which can damage the transfer box or give false torque readings, our linked axle technology ensures both front and rear rollers turn in perfect synchronisation. Accurate, real-world performance data every time.

Linked Axle TechnologyFront and rear rollers synchronised for true AWD compatibility
xDrive SafeBMW's intelligent AWD system is fully protected throughout all runs
Accurate, Repeatable DataEvery run logged with ambient pressure and temperature for consistency
Full Printout IncludedYou receive a before and after dyno sheet with all power and torque figures

FAQs

BMW 40d Tuning Questions

How much power will a Stage 1 remap add to my BMW 40d?

Our Stage 1 maps are custom-built on our in-house 4WD dyno and tailored to your exact BMW 40d, never a generic off-the-shelf file. You'll see a substantial, fully dyno-proven gain in both power and torque; the headline figures for this platform are shown at the top of this page. Because every map is refined over multiple runs, the results are realistic, repeatable and safe.

Is remapping my BMW 40d safe and reliable?

Yes. We tune strictly within the safe mechanical limits of your BMW 40d's engine and gearbox, monitoring temperatures, pressures and torque loads across multiple dyno pulls. We've spent 15+ years tuning these platforms, so our maps prioritise long-term reliability alongside performance.

Will a remap affect my warranty or insurance?

A remap is an aftermarket modification, so it's the owner's responsibility to declare it to their insurer. Our maps are fully reversible, we can return the BMW 40d to its factory software whenever you need, for example before a main-dealer visit.

Is the remap reversible?

Completely. It is fully reversible: your BMW 40d can be put back to its factory software at any time.

Will tuning improve my BMW 40d's fuel economy?

We tune for performance, not fuel economy, so we don’t promise or guarantee any MPG saving. How much fuel the car uses comes down mostly to how it’s driven, and using the extra performance will use more.

How long does it take, and do you tune on a dyno?

Most Stage 1 tunes are completed within a few hours; allow up to a day for combined ECU and gearbox work. Every BMW 40d is mapped on our in-house 4WD dyno in Warrington, never on the road, so the result is measured and consistent. You're welcome to relax in our customer waiting area while we work.

Can you tune a BMW 40d built from June 2020?

Yes. G-series 40d models built from June 2020 have a locked ECU, and we unlock it in-house on our own bench on the same visit, then tune it as normal. The unlock adds £100 to your tune. Cars built from June 2026 use a newer lock that can't be opened yet, so we can't tune those for now.

Check Your Vehicle