Cummins unveils new 550 hp QSB6.7 for pleasure boats

Cummins has announced the new QSB6.7 engine which will become available for the South Pacific recreational marine market in October 2013.

With a top rating off 550 hp, the new 6.7-litre QSB boasts the best power density in its class.

While meeting US EPA Tier 3 emissions standards, the QSB6.7 offers better performance along with lower noise and vibration than Cummins’ popular QSB5.9, all without sacrificing fuel economy.

Cummins reached US Tier 3 emissions levels by improving the efficiency of the in-cylinder combustion events. A new fuel calibration strategy allows for less wasted fuel, creating less particulate matter and resulting in cleaner exhaust.

“While reducing emissions levels often means a sacrifice in performance and fuel efficiency, Cummins has avoided that sacrifice,” says Tony Lee, Cummins South Pacific marine business manager.

The QSB6.7 not only generates more power than the QSB5.9 (480 hp maximum) but also higher torque, which means better acceleration and maintained speed through turns.

The 6.7-litre Cummins also employs a new fuel calibration strategy. Unlike most marine engines, the QSB6.7 is calibrated for optimal fuel economy at cruise speeds, where the engine is most often used, rather than at wide-open throttle.

“The QSB6.7 is sociably improved, offering exceptionally low cold-start smoke levels and significant sound reduction at cruise and rated speeds compared with the QSB5.9,” says Lee.

The QSB6.7 shares many of the base engine design features of the QSB5.9. “The new engine is an evolution of the 5.9-litre QSB which has a proven record of reliability and durability in not only marine but also automotive, industrial and power generation applications,” Lee points out.

The QSB6.7 will be available from 230 to 550 hp for the pleasure boat market.