Tech Q & A


How do truck manufacturers configure their production engines on a dyno to get maximum horsepower and torque figures they publish in their vehicle specs? Davey Lucas, Boyertown, PA

Truck manufacturers use a variety of engine testing configurations when setting power figures. Their published engine horsepower ratings follow an SAE standard that spells out the engine’s equipment along the testing protocols.

The SAE standard specifies production engine internals, the complete intake system including stock intake manifold, throttle body, inlet tube and air filter. For the exhaust, the production manifolds or headers are fitted, but not the catalytic converters. A variety of tests are averaged to arrive at the published figure.


How is DEF kept from freezing in the winter? Does DEF need any winter additive?

William F. Boswell, Millersville, MD

There is a small heating element built into the DEF tank and lines. The system allows for a brief warm up period as a failsafe in case of a really hard freeze. The element automatically activates when the temperature drops below freezing. As for additives, Cummins says this: While an additive could improve freeze point of the mixture, the 32.5 percent solution is very specific to providing NOx reducing properties. Any further blending or adjusting of the DEF mixture will impede its ability to perform correctly and may cause damage to the SCR components. Additives of any type are not approved for use in DEF today.


I have seen the Ram commercial with the side storage in the bed of their half-ton pickup. Will Ram offer this feature on the HD pickups? Carl Dodd, Denton, TX

Yes, the RamBox will be available on the 2012 Ram HD pickups. The RamBox will be available with the 6-foot-4-inch cargo box, providing about 9.8 cubic feet of cargo capacity. We also have learned that Chrysler is working on a RamBox for dual-rear wheel models as well.