M-Engineering M-Tuner ECU Calibration Suite for McLaren M840T

The McLaren M840T responds extremely well to calibration, whether the car is completely stock, running basic bolt-ons or being developed into a much more serious power package. M-Engineering's M-Tuner system gives the 720S, 750S, 765LT, Senna and GT a complete ECU tuning platform with multiple fuel maps, live map switching, datalogging and the ability to flash the car through the OBD port after the initial ECU setup.

We use M-Engineering calibrations throughout our own McLaren programs because the system gives us the flexibility to support everything from a lightly modified street car to dedicated track and high-power builds without locking the customer into one fixed calibration.

One tuning platform, multiple stages

M-Tuner supports M-Engineering's range of off-the-shelf calibrations for the M840T platform. Original purchasers can move between supported Stage 1, Stage 2 and Stage 2+ calibrations as their vehicle evolves without purchasing the calibration suite again. Custom and ProTune options are also available for combinations that fall outside the standard map configurations.

• Stage 1: Calibration for vehicles running a stock or near-stock hardware configuration.
• Stage 2: Calibration intended for vehicles with the supporting hardware required by M-Engineering's Stage 2 specification.
• Stage 2+: Supports more advanced fuel and hardware configurations, including M-Engineering's available Stage 2+ package.
• Custom / ProTune: Available for different turbochargers, fuel systems, fuels and other configurations outside the standard map notes.

Because exact hardware requirements can vary by model and calibration level, contact us before ordering if you are unsure which stage matches your car.

Live Map Switching

One of the biggest advantages of the M-Engineering system is on-the-fly Live Map Switching. Multiple calibrations can be stored in the ECU at the same time and selected using the factory controls, allowing you to change maps without connecting a laptop or reflashing the car every time fuel or use changes.

Standard Stage 1 and Stage 2 packages are typically configured with:

• Slot 1: 91 Octane
• Slot 2: 93 Octane
• Slot 3: 100+ Octane
• Slot 4: Valet Mode, limiting boost, load and throttle

Different map-slot configurations can be requested when ordering depending on the vehicle, fuel and intended use.

What M-Tuner includes

• M-Tuner v3 wireless OBD flashing dongle
• M-Engineering calibration files for your specific M840T application
• On-the-fly Live Map Switching
• High-speed datalogging
• Live vehicle data
• Read and clear faults
• Dyno Mode enable and disable
• Auto Start/Stop disable
• Left-foot braking support
• Kickdown disable
• Loud Start functionality
• M-Engineering calibration support

Supported McLaren models

This version of M-Tuner supports McLaren models equipped with the 4.0L M840T engine, including:

• McLaren 720S and 720S Spider
• McLaren 750S and 750S Spider
• McLaren 765LT and 765LT Spider
• McLaren Senna
• McLaren GT

M-Engineering continues to develop the platform, so calibration availability and supported features can vary between specific models and software versions.

Built for cars that continue to evolve

The biggest benefit of M-Tuner is that the calibration does not have to remain static as the car changes. A 720S that starts with a basic Stage 1 calibration can later move into downpipes, additional fueling, Stage 2+, upgraded turbochargers or a custom setup while continuing to use the same M-Tuner ecosystem.

For more advanced motorsport builds, M-Engineering also offers additional functions through its Motorsport Tuning Package, including features such as Rolling Anti-Lag, custom closed-loop boost control, staged injection and fan override.

Initial ECU setup

M-Tuner requires a one-time bench procedure before OBD flashing is enabled. The ECU must be removed from the vehicle and sent in for this initial service. Once completed, future supported calibration changes can be flashed through the OBD port using M-Tuner.

M-Engineering typically lists approximately 24-hour turnaround after receiving the ECU, although actual turnaround can vary.

Important note for McLaren 750S

Early 750S vehicles may use the older “822” ECU operating system. M-Engineering requires these vehicles to be updated to the newer “830” operating system before tuning. If you have a 750S, contact us before sending the ECU so we can confirm the software requirement and avoid unnecessary turnaround time.

RWE support

There are a lot of variables once you start modifying an M840T McLaren, especially once fuel systems, downpipes, turbochargers and alternative fuels enter the picture. If you are unsure which stage or calibration is appropriate, contact us with your current hardware, fuel and goals. We can help determine the correct starting point and whether an off-the-shelf map or custom calibration makes more sense.

ECU Shipping: This product requires the ECU to be shipped in for the initial bench procedure. Follow the shipping instructions supplied after your order is processed.

Disclaimer: ECU calibration and additional tuning features can affect vehicle reliability, emissions compliance and manufacturer warranty coverage. The vehicle owner is responsible for ensuring the vehicle is mechanically sound, correctly modified and operated within the requirements of the selected calibration.

Return Policy: M-Engineering software calibrations are vehicle-specific and all sales are final and non-refundable.

California customers: These calibrations are intended for off-road and competition use where applicable. California customers must complete the required RWE CARB compliance documentation before the ECU can be returned.