Top 100: Un-EGR Needs No Plumbing

Mack split the truck market into highway and vocational segments when they evolved the E-Tech E7 into the ASET engines with a different kind of exhaust-gas recirculation (EGR) for each segment. All 16 ASET configurations work from a six-cylinder, 12-liter platform. Mack developed simpler internal-EGR for DM, RD, and Granite trucks. It uses electronic control and fancy valve work to blend some exhaust with intake air inside the engine. There are eight internal-EGR configurations with ratings from 300 to 460 horsepower, and torque ranges from 1,200 to 1,560 foot-pounds. Vision trucks and road tractors get a variable-geometry turbocharger with cooled EGR. They range from 310 horsepower and 1,360 foot pounds of torque to 460 horsepower with 1,660 foot-pounds of torque. The internal-EGR engines cost $3,300 more, and the cooled-EGR ASET engine costs $5,100 more than their E-Tech predecessors.