Rocket Fuel
x15 efficiency series front Turbo

Cummins 2017 X15 Efficiency Series.

Cummins X15 increases value in every way possible, from having the highest fuel economy of any engine in its class to offering the longest maintenance intervals, for lower costs and increased uptime. In fact, compared with a 2010 Cummins ISX15, the latest model provides a 40% reduction in maintenance costs over the first half-million miles – from close to $14,000 to less than $8,000.

A new Single Module™ aftertreatment system takes up 60% less space, weighs up to 40% less than the unit it replaces and includes a new UL2 dosing system, for even greater reliability. The smaller package size allows the Single Module to be placed closer to the engine, for better heat management with a reduced number of regenerations. Plus, the integrated engine brake now delivers up to 400 braking horsepower at just 1300 rpm, right where you drive. When the X15 pulls on the reins, you can go light on the brake pedal, saving wear and tear on your service brakes while staying in total control.

Of course, the ultimate value comes from having an engine you can depend on, every day and every delivery. The X15 engine has reliability and durability you can count on, with over 9 million miles of real-world testing behind it.

Improvement graph

The Industry’s Best Fuel Economy.

If you’re driving a 2010 truck, you can get up to 20% better fuel economy with the X15 SmartAdvantage Powertrain alone. If you’re currently getting 6.5 mpg, you’ll see that number jump to at least 7.5 mpg, and probably closer to 8 mpg. For a truck running 120,000 miles per year, that means about 2,500 fewer gallons of fuel going into the tank – a direct savings of $7,500 per truck at $3 a gallon.

The SmartAdvantage Powertrain is a key contributor to increased fuel efficiency, particularly in over-the-road (OTR) trucking operations in which the small-step overdrive transmission yielded the greatest benefits. Direct drive transmission options for the SmartAdvantage Powertrain lineup enable less-than-truckload (LTL) and regional-haul operators to get a spec ideally suited for duty cycles with multiple delivery stops and lower average road speeds.

Eight X15 SmartAdvantage Powertrain options are now available:

Top Gear
Cummins Engine Power hp (kW) Peak Torque
lb-ft (N•m) @ rpm
Eaton® Transmission
Axle Ratios
Small-Step Overdrive X15 400 SA 400(298) 1450/1650 (1966/2237) @ 1000 FAOM- 14810S-EC3 2.64
X15 400 SA 400(298) 1550/1750 (2102/2373) @ 1000 FAOM- 15810S-EC3
X15 450 SA 450 (336)
X15 400 SA 400 (298) 1550/1850 (2102/2508) @ 1000 FAOM- 18810S-EC3
X15 450 SA 450 (336)
X15 500 SA 500 (373)
Direct Drive X15 400 SA 400(298) 1550/1750 (2102/2373) @ 1000 FAM- 15810B-EA3 2.26
X15 450 SA 450 (336)

Fewer Downshifts. More Savings.

Whether you’re hauling 80,000 pounds through the Rockies or you’re an expedited shipper committed to delivering at a moment’s notice, you need a big-bore 15-liter engine to get the job done – but not just any big-bore: You need the X15. Cummins X15 Efficiency Series has the torque you need to maintain higher average road speeds with fewer downshifts going through hilly terrain. The fact is, the X15 Efficiency Series will deliver best-in-class fuel economy on those kinds of runs, without impacting your trip time. Advanced combustion technology on the 2017 X15 also delivers better throttle response. Cummins 500-hp X15 Efficiency Series is the ultimate package, pleasing drivers and accountants alike, and can be expected to drive our industry-leading resale value to even greater heights down the road.

Graph: Torque X Power x15 efficency engine

Direct Drive Or Overdrive.

The X15 SmartAdvantage Powertrain using direct drive transmissions is designed to maximize fuel economy in specific duty cycles and operating conditions. Some regional-haul or LTL truckers will see better results using the small-step overdrive transmission. This chart shows the benefits of each:

Condition Direct Drive Overdrive
Higher Efficiency In Top Gear Conditions  
More Even Steps, Easier To Drive (With Manual)  
Downspeeding Capability
Higher Gradeability And Startability In Low Gears
Less Prone To Driveline Wear

Rookies Drive Like Pros With ADEPT.™

Cummins is continually setting new benchmarks for the trucking industry. Major technological advancements in the X15 platform include ADEPT with SmartCoast,™ SmartTorque2 (ST2) and Predictive Cruise Control (PCC). Together, they are proven to deliver up to 6 percent better fuel economy. And it’s not just X15 SmartAdvantage; ADEPT features are also backwards-compatible for ISX15 engines dating back to 2013, coupled with Automated Manual Transmissions.

This video explains how ADEPT technology works, and previews new technologies to come:

To learn more about the proprietary technology, features and specs of Cummins 2017 X15 Efficiency Series engine, including the XPI Fuel System, VGT® Turbocharger, fully integrated aftertreatment system and more, check out

For additional details about the Eaton Fuller Advantage® 10-speed automated transmission, visit Eaton Heavy-Duty Automated Transmissions.