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RENNtech ECU+ Upgrade | W212 | E 550 | 540HP / 705 LB-FT | 4.7L V8 BiTurbo | M278

ECU+ Upgrade | 540HP / 705LB-FT | +105HP / +262LB-FT
SKU: ECU:54.212.E550BT
Retail price without tax: $2,480.00

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RENNtech HHT (hand held tuner) allows you the unlimited ability to switch between tuned and stock ECU programming and requires no ECU removal!

Our 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.

Our proprietary ECU upgrade for the Mercedes M278 Biturbo engine offers huge gains in performance across the entire RPM range without sacrificing around town comfort or daily driver reliability.

With the newest update of their Software Upgrade for the M278 – 4.7L V8 BiTurbo, RENNtech boosts the 550-Series to AMG Power Levels. The RENNtech upgraded M278 now produces 540 HP and 705 LB-FT at crank.

Compared to power numbers by Mercedes-Benz, the E 550 gains up to 105 HP and 262 LB-FT. This Software update delivers up to 10 HP and 99 LB-FT more than the previous version.

The vast amount of increased torque across the entire RPM range gives the 550 an extra edge to compete with AMG powered vehicles. All this without sacrificing around town comfort and daily driver reliability.




  • 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 14% Drivetrain loss on RWD vehicles.
  • 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. Please call for details and Race fuel options +1-561-845-7888.



Performance Numbers Overview 


E550 (W212 | PFL MY2012-13 | RWD | M278 | 4.7L V8 BiTurbo) Stock Performance (at crank):

  • Rated by Mercedes-Benz:      402 HP @ 5,500rpm; 443 LB-FT @ 2,000-4,500rpm
  • Rated by RENNtech:               435 HP @ 5,500rpm; 443 LB-FT @2,800-3,900rpm
    • Note: Mercedes M278 engine performance when measured, obtains higher power numbers than rated from factory.



E550 (W212 | PFL MY2012-13 | RWD | M278 | 4.7L V8 BiTurbo) Modified Performance (at crank):

  • Rated by RENNtech:               540 HP @ 5,500rpm; 705 LB-FT @ 3,700rpm
                                                    464awhp @ 5,500rpm; 606awtq @ 3,700rpm
    • Crank Performance Numbers are calculated with a 14% Drivetrain loss on RWD vehicles.



Contact us

7825 SW Ellipse Way, Stuart, FL 34997
(+1) 561 - 845 7888
Mon - Fri 9am - 6pm


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7825 SW Ellipse Way - Stuart, FL 34997
TEL: 561.845.7888 FAX: 561.845.6777 E-MAIL: