SALT LAKE CITY. As part of a "boot camp," almost 1,000 International dealers are getting a chance to test drive Navistar's new MaxxForce 15 diesel installed in two ProStar+ tractors. Developed in just two years from Caterpillar's discontinued C15 engine, the new 15-liter fills out the top end of Navistar's proprietary engine family. It is the only line of diesels not using selective catalytic reduction (SCR) to meet EPA 2010 emissions requirements.

See the video of the 15-liter MaxxForce15

Divided into seven waves of two-day sessions at Miller Motor Sports Park, the dealers are also spending time comparing torn down diesels from all of Navistar's competitors with the company's main big bore engine, the 13-liter MaxxForce 13.

While Navistar believes that 13 liter diesels will displace 15 liter engines as the dominant power plant for over-the-road Class 8 tractors, "the 15 liter will still have a place where customers need more than 500 HP," said Tim Shick, dir. of engine sales and marketing.

The new MaxxForce uses the block, oil pan, crankshaft, connecting rods and head castings from Caterpillar's C15, which Cat stopped selling in the U.S. truck market at the end of 2009. Navistar engineers adapted the MaxxForce 13 common rail fuel system, air system, twin turbos and "advanced EGR" system to create a diesel that meets 2010 emissions without SCR and diesel emissions fluid, according to Shick.

Calling the new engine "heavy and capable," Shick said it weighs more than any other 15L on the market, but that extra weight is offset by not requiring a 400 to 500 lb. SCR aftertreatment system. Dealers are currently taking orders for ProStar+ and vocational PayStar models with the MaxxForce 15 with rating ranging from 450 to 500 HP and peak torques between 1550 and 1750 lbs.-ft. The severe duty International 9900 will be available with ratings up to 550 HP/1850 lbs.-ft in December, according to Shick.

The company's premium LoneStar tractor will get the new 15L next year, as well as a new 500-HP version of the MaxxForce 13, Shick said.

Fuel economy for the new engine "is within a couple of tenths of the MaxxForce 13," which is "6.5 MPG for a ProStar with full aerodynamics and loaded to 80,000 lbs.," Shick said during a press briefing. Base warranty is 3 yrs./350,000 mi.