RennTech Performance ECU+ Upgrade For Mercedes-Benz W166 ML 550 Biturbo

VENDOR: RennTech

SKU: 54.166.ML550BT

All orders will include an AutoTalent window decal


RennTech HHT (hand held tuner) allows you the unlimited ability to switch between tuned and stock ECU programming and requires no ECU removal. RennTech proprietary tuning module stores both the RennTech tuned file and your vehicles stock file. The module plugs directly into the OBD2 port and delivers the file you choose directly to the ECU. Programming takes only a few minutes and the vehicle can be reflashed at any time as many times as you wish.

RennTech has been at the forefront of ECU tuning since electronic engine management started to show up in vehicles during the mid 1980s. RennTech experience, countless hours of in-house research, development and exhaustive testing ensure that our proprietary ECU upgrade offers incredible performance gains and rock solid daily driver reliability.

RennTech tuning software for Mercedes offers significant gains in horsepower and torque across the vehicle's entire power band. By modifying ignition timing and throttle mapping, optimizing air-to-fuel ratios, increasing the engine's rev limiter and modifying boost mapping for turbo-charged vehicles, RennTech performance software unleashes the true potential of your Mercedes.

RennTech Software Upgrade for the M278 – 4.7L V8 BiTurbo, RennTech  boosts the 550-Series to AMG Power Levels. The RennTech upgraded M278 now produces up to up to 540 HP and 705 LB-FT at crank. Compared to power numbers by Mercedes-Benz, the ML 550 gains up to 92 HP and 167 LB-FT. This Software update delivers up to 10 HP and 99 LB-FT more than the previous version.


We have found the M278 engine stock performance numbers vary from the baseline figures claimed by Mercedes Benz. We typically see higher baseline numbers than claimed by the factory.

Power gains are calculated based on stock numbers measured by RENNtech.

Crank Performance Numbers are calculated with a 18% Drivetrain loss on 4MATIC SUVs.

Our numbers will be dependent on conditions and fuel quality. 93+ Octane gasoline is mandatory with this Performance Upgrade.

States known for poor fuel quality have to be supplied with a lower power setup


  • Gains: +92HP / +167LB-FT
  • Long-lasting and driver reliability
  • Significant gains in horsepower
  • Increases the performance
  • Significant gains torque 
  • Increasing the engine's rev limiter
  • Incredible performance gains

Stock Performance:

  • 429 HP @ 5,500rpm; 516 LB-FT @ 2,000-4,500rpm
  • 448 HP @ 5,500rpm; 538 LB-FT @2,800-3,900rpm

Modified Performance:

  • 540 HP @ 5,500rpm; 705 LB-FT @ 3,700rpm
  • 443 awhp @ 5,500rpm; 578awtq @ 3,700rpm

      Vehicle Fitment:    

      • 2012 Mercedes-Benz W166 ML 550 Biturbo
      • 2013 Mercedes-Benz W166 ML 550 Biturbo
      • 2014 Mercedes-Benz W166 ML 550 Biturbo
      • 2015 Mercedes-Benz W166 ML 550 Biturbo


                                Images are for representation purpose only and may differ depending on application.