Mercedes S550 Biturbo (2007-2013) – RENNtech Intermediate ECU upgrade





RENNtech intermediate level ECU upgrade for the Mercedes M278 engine still offers huge gains in performance across the entire RPM range, but with a slightly reduced peak HP and torque from their standard tune.

This is ideal for customers who want increased performance in their daily driver without worry of extra strain on driveline components or for areas and countries with extreme altitudes, temperatures or fuel quality concerns.

Their intermediate ECU tune increases performance from 429 HP and 516 lb/ft torque to 510 HP and 585 lb/ft at the crank! This is a slight reduction from their standard tune but still offers white knuckle performance at one of the most affordable price points in the tuning market.

  • Note: They have found the new M278 engine stock performance numbers vary from the baseline figures claimed by Mercedes Benz. They typically see slightly higher baseline numbers than claimed by the factory.


S 550 (W221- M278 Biturbo Engine) Stock Performance:

  • 429 HP @ 5,250 RPM; 516 LB-FT @ 1,800 RPM
  • Note: Mercedes M278 engine performance when measured obtains higher numbers that rated from factory.


Modified Performance:

  • 510 HP @ 4900 RPM; 585 LB-FT @ 4100 RPM



  • +81 HP / +69 LB-FT


*NOTE – We would need either the ECU or the vehicle bringing to our premises in Cheshire


Due to some of the products coming direct from RENNtech USA please allow 7-10 days for delivery

Prices may vary in accordance to the current exchange rate, please contact us for the current confirmed price

Our refunds policy can be found here