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 GL 550 gains up to 66 HP and 139 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.

X166 - GL 550 – M278 | 4.7L V8 BiTurbo Stock Performance:

• Rated by Mercedes-Benz:       429 HP @ 5,250 RPM  |  516 LB-FT @ 1,800-3,500 RPM
• Rated by RENNtech:                474 HP @ 4,900 RPM  |  566 LB-FT @ 2,350-3,650 RPM 

X166 - GL 550 – M278 | 4.7L V8 BiTurbo RENNtech Upgraded Performance:

• Rated by RENNtech:           540 HP @ 4,500 RPM  |  705 LB-FT @ 2,850-3,450 RPM