LOUISVILLE, KENTUCKY-- Mack Trucks introduced Super Econodyne Direct, a new fuel-saving option that combines the Super Econodyne engine rating with a direct-drive version of its mDrive automated manual transmission. here at the Mid-America Trucking Show. 

“Our Super Econodyne rating was previously only available with the overdrive version of the mDrive, but the recent release of numerically lower rear axle ratios allows us to use the direct drive variant,” said Scott Barraclough, Mack technology product manager. “The result is up to 1% better fuel efficiency on top of the 3% Super Econodyne already delivered on its own.”

Despite having a higher top gear ratio, the direct drive mDrive is more efficient because it features reduced parasitic losses. This results from torque not transmitted to the direct drive mDrive’s countershaft while in top gear. Instead, the transmission's input and output shafts are essentially locked together, according to Mack.

Super Econodyne Direct is best suited for applications of 80,000 pounds GCW or less where drivers remain in top gear for a large percentage of the time. It also works best on mostly flat terrain and when drivers remain mostly in constant speed.

Mack’s Super Econodyne rating fully integrates Mack MP engines and the Mack mDrive to deliver fuel savings. The integrated powertrain enables lower engine cruise RPM to save fuel, without impacting power or performance. Super Econodyne-rated Mack engines cruise at approximately 1,150 rpm, a reduction of 200-300 rpm from a typical highway cruise rpm, which results in up to 3% improved fuel efficiency.

Super Econodyne ratings are available for the 11-liter Mack MP7 and 13-liter MP8 engines.

Mack also announced that its 2017 MP8 engine with turbo compounding is now available for order. The turbo compounding system gives the engine an improved operating range and holds the top gear when cresting a hill, even with the engine rpm decreasing. 

Available exclusively with Mack’s Super Econodyne downspeeding package, the MP8 with turbo compounding converts wasted energy from the exhaust into mechanical energy that is fed back to the engine. The system adds up to 50 additional horsepower, improving fuel efficiency by up to 8.8%, according to Mack. The additional power generated by the turbo compounding system allows the engine to maintain full torque as low as 900 rpm.