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M278 ECU Tune
Purchase M278 ECU Tune
  • SKU: 01-278-00828-6

    M278 ECU Tune

  • Advertised gains are estimates of HP and Torque “at the engine” calculated from gains as measured on a Dynojet Dynamometer in ideal conditions and typically show the largest possible change.  Actual gains are dependent on the following: Learn More about Crank HP Vs Wheel HP

    Model – Manufacturers use the same engine in multiple model vehicles and often times they are in a different state of tune, for example: 2008 C63 and a 2008 CLK Black Series.  Both have the same engine, but the C63 has 451hp while the CLK63 has 500hp.  Naturally the C63 will show more gains as it starts at a lower level.

    Model Year – Similar to above, as time progresses, Manufacturers tend to slightly increase power output via software from one year to the next or offer “Performance Packages” with increased power.  The engines remain largely unaltered and as a result, final tuned output remains the same, while the gains are lower as the starting point is now higher.

    Fuel – Fuel quality is HIGHLY important with performance vehicles.  Low quality and/or low octane fuel will greatly impact engine output and potentially even engine health.  Top tier brand premium fuels should always be used to achieve the best results possible.

    Drivetrain – All wheel drive has higher drivetrain losses than rear wheel drive.  This results in lower numbers when testing on a chassis dyno.  Wheel/tire size and weight will also impact chassis dyno results

    Weather/Conditions – Temperature, humidity, altitude, and air density all impact engine performance.  Heat, high humidity, and thin air will all work towards reducing engine output

    Engine Health – Higher miles tends to result in increased build up and lower compression which can and will impact engine output.  Properly maintained engines will have better performance than abused or neglected engines.

    Supporting modifications – The highest power levels require supporting modifications.  Depending on the engine, this could mean forged internals, built transmission, upgraded fuel system, 110+ octane race fuel, etc.

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  • CARB EO: D-691-1
  • Prop 65 warning

    This product can expose you to chemicals including carbon black, silica - crystalline, formaldehyde, and lead which are known to the State of California to cause cancer, and lead, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to

Weistec Horsepower 540
Weistec Torque 715
CARB Exempt ID D-691-1
Manufacturer Weistec
Street legal in all the US States Yes
Engine Family M278
See more
year make model trim engine
2013 Mercedes-Benz CLS550 Base (W218) Twin Turbo 4.7L V8 (M278)
2020 Mercedes-Benz SL500 Base (R231) Twin Turbo 4.7L V8 (M278)
2019 Mercedes-Benz SL500 Base (R231) Twin Turbo 4.7L V8 (M278)
2018 Mercedes-Benz SL500 Base (R231) Twin Turbo 4.7L V8 (M278)
2017 Mercedes-Benz SL500 Base (R231) Twin Turbo 4.7L V8 (M278)
2016 Mercedes-Benz SL500 Base (R231) Twin Turbo 4.7L V8 (M278)
See more

Product Description

All 2020 models require bench flashing at this time.

ECU Tuning Process: How do I get my ECU tuned?

540 Horsepower, 715 Ft-Lbs Torque
As an industry leader in tuning and calibration, Weistec Engineering is proud to introduce the much anticipated ECU tune for the bi-turbo M278 vehicle lineup. After months of painstaking dyno and road tuning, we are proud to introduce the most powerful ECU upgrade ever released for the M278 engine. Fully developed in house, our ECU tune has surpassed the 540 horsepower* mark on a completely stock vehicle with no other modifications.

CARB EO# D-691-1

With a keen understanding for optimal running conditions for the M278, we have revised many features of the factory ECU programming which creates an astounding 540 horsepower* and 715 torque* at the engine on California pump 91 octane all while being street legal.

ECU Tuning Process: How do I get my ECU tuned?

Key Features:

  • 540 Horsepower*

  • 715 Ft-Lbs Torque*

  • Eliminate Top Speed Limiter*

  • Increased Throttle Response

  • Optimized Boost, Fuel and Spark

Tuning Process: Cypher Handheld Tuner