Mll promises more
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by Steve Sturgess • Cummins has unveiled its next generation M11 engine due in April. It borrows technology from the Signature 600 unit and promises better fuel economy with doubled service intervals.
The ISM 11-litre shares engine electronics with the Signature 600 and uses the same electronic control module (ECM).
With a new 425hp (317kW) top power rating (450hp (336kW) for fire and coach), the ISM overlaps the N14 ratings as that engine nears the end of its life. The ISM 425 also boasts 2,100Nm (1,5501bft) of torque.
A Signature-sourced wastegated turbocharger is included on the 425 and 450, although sized for the smaller ISM's displacement. All ISMs have the serpentine accessory drive belt with an automatic tensioner off the front of the 600hp Signature.
Retarding horsepower goes up 20hp (15kW) at the top end for a maximum 370hp (276kW) thanks to refinement to the Jacobs-engineered C-Brake.
Other power ratings run from 280 to 425hp and the range includes Cummins' dualtorque ESP and new construction-orientated V ratings. A VSP dual-personality increases torque at the low end when loaded and de-rates the engine for empty return runs. Also new is a SmartTorque output for the 330, 350 and 370hp (246, 260 and 276kW) that boosts torque in the top two gears. SmartTorque means lighter service transmissions from Eaton and Mentor.
One innovative feature is Driver Rewards. The ECM tracks driver performance against fleet-set parameters and when a driver scores fuel economy performance above the set points, the electronics can be programmed—in the case of an ESP engine—to allow a smaller speed change before the engine switches to the high-torque value.
Oil and filter change are now set at 50,000 miles (80,000 km). For light-duty operation the interval can improve to 65,000 miles (104,000km). New Mll main features • Electronics from the Signature 600 • 2-4°i improved fuel economy (claimed) • Service intervals at 50,000 miles (80.000km) • Horsepower ratings from 330-425hp • Max torque 2,100Nm (1.550Ibft)