ECU Hand Held Tuner HHT for Mercedes M278

The Renntech ECU Hand Held Tuner HHT (part number ECU:54.222.S550BI) is an intermediate-level ECU upgrade designed for the Mercedes M278 engine, specifically the 4.7L V8 BiTurbo found in the W222 S550 models from 2014-2017. This tune offers significant performance gains throughout the RPM range, providing a "white knuckle" experience for daily drivers while being mindful of driveline component strain. This upgrade takes the stock performance of the M278 engine from approximately 449 HP and 516 lb/ft of torque to an estimated 500 HP and 625 lb/ft of torque at the crank. These figures are calculated assuming a 17% drivetrain loss for 4MATIC vehicles. Note that RENNtech has observed that actual stock M278 engine performance often exceeds the factory-rated numbers. For optimal performance and to ensure engine longevity, this upgrade mandates the use of 91+ Octane gasoline. In regions known for lower fuel quality, a modified, lower-power setup may be necessary; contact RENNtech for details and race fuel options. This tuner is specifically designed for the W222 chassis S550 with the M278 engine and 4.6TT configuration.