Well this is something we're not used to seeing...

 Emission downgrade kits for engines operating outside of North America and Europe. Cummins and Caterpillar recently announced they will offer engine modifications for Tier 4 interim (Tier 4i) and Tier 4 final non-road diesel engines that allow the sale of used Tier 4 equipment in markets with more relaxed emission standards. The process of modifying the engines entails emission de-certification of the engines, and could involve removal of aftertreatment systems (DPF's).

 Cummins introduced a "Sulfur Tolerance Kit" which provides new engine calibrations and hardware to operators and dealers who could end up selling their Tier 4 piece(s) of equipment in the used market. The kits allow engines to be much more tolerant of fuels containing more sulfur than ULSD.

 Caterpillar will offer modification processes to its Tier 4 engines making less than 130 kW (174 hp), in which the emission aftertreatment systems can be removed. According to Cat, engines operating between 130 kW and 895 kW will not require any modification. Starting in 2014, customers in lesser regulated countries will be able to have these de-certification modifications performed by local Cat dealers. In addition, Cat intends to also include Tier 4 final equipment in the de-certification program in the future.