COLUMBUS, Ind. The tiff between diesel engine makers over emissions technology appears to have spilled over into other areas.

Cummins says it has "indisputable evidence" that prove its ISB engines get "significantly better" miles per gallon than International MaxxForce 7 and MaxxForce DT engines.

How much better? asks Cummins.

"On a closed track, simulating a rural school bus route, the ISB delivered 7.6 percent better fuel economy than the MaxxForce DT," Cummins says in its latest bus engine newsletter.

"On a closed-track simulation of an urban school bus route, the ISB got 17.2 percent better mpg than the MaxxForce 7. The difference was even greater on an interstate route, simulating travel to an activity outside the school district, (where there was) 18.8 percent better mpg," Cummins reported.

The testing, says Cummins, was conducted with an independent third party and Cummins in-house engineers, using Society of Automotive Engineers methodology, with like horsepower and torque for the competing engines, on vehicles with comparable specifications and loads.

According to Cummins, the test results have potentially significant financial ramifications.

"Based on these results, each ISB-powered school bus in a typical urban fleet running 15,000 miles per year will use 433 gallons less fuel and will cost (an operator or a school) district $1,300 less to run than a bus equipped with a MaxxForce 7.

"This is assuming 15,000 miles driven annually and a fuel cost of $3 per gallon."

The bottom line, Cummins asserts, "is that across all types of vehicles, routes and loads, the ISB consistently gives bus fleets the best fuel economy of any engine in its class."

Additional information is available in a press release and the Cummins ISB Fuel Economy White Paper, which can be found at www.everytime.cummins.com.