Navistar announced the results of its latest round of fuel-efficiency testing today, which the company said demonstrates that their International ProStar tractor is the most aerodynamic and fuel-efficient Class 8 truck on the road.
The testing included wind tunnel and over-the-road testing of the ProStar model compared to Freightliner’s Cascadia tractor and Kenworth’s T660. The results of the wind tunnel testing showed that the ProStar is 7.3% more aerodynamic than the Cascadia and 8.2% more aerodynamic than the T660, according to Bob Weber, chief engineer, Heavy Vehicle Center for Navistar. Over-the-road-testing against a similarly spec’d Freightliner Cascadia confirmed that the ProStar was also 7% more fuel efficient than the Cascadia, Navistar reported.
The wind tunnel tests-- conducted at the National Research Council Institute (NRC) for Aerospace Research site in Ottawa, Canada in March and April according to SAE J1252 wind tunnel testing practices— simulated driving environments ranging from no wind to a 12 mph crosswind that the company said replicates 95% of all real-world driving conditions.
To further verify the wind tunnel results, Navistar also contracted the Transportation Research Center, Inc. to conduct three, 444-mile over-the-road tests of the ProStar and the Cascadia. The tests were run in Northern Indiana, following the TMC Type IV test procedures. “Over-the-road testing provides the most conclusive results as it takes powertrain [performance] into account,” Weber noted.
“If we can achieve a 2% improvement in aerodynamic performance, we can achieve a 1% improvement in fuel economy,” said Ron Schoon, chief engineer for aerodynamics of the Heavy Vehicle Group. The result, the company said, can add up to a savings of 1,400 gallons of fuel and $5,800 per year, or nearly $30,000 over a five-year period.
Navistar’s TMC Type IV testing builds upon a SAE Type III test the company conducted last fall that it said showed the ProStar to be 5.7% more efficient than the Cascadia. The company added that it would return to NRC later this summer for additional tests.
Steve Gilligan, assistant general manager, Heavy Vehicle Center, also announced that Navistar will be offering pre-determined, “Maxximum MPG” spec packages for 2009 model year ProStar, LoneStar, TransStar and 9000 Series units. Customers ordering