[mtlakejim]

Originally Posted by vipermanden

How does Selective Catalytic Reduction (SCR) affect a vehicle's performance?

Since the introduction of diesel emissions legislation, truck manufacturers have battled to reduce emissions while maintaining and improving engine torque. Selective Catalytic Reduction (SCR) is an aftertreatment technology, which means that it deals with emissions without adapting combustion conditions. In contrast, Exhaust Gas Recirculation (EGR) functions by reducing combustion temperatures, thereby reducing NOx. The use of SCR has allowed therefore manufacturers to tune engines, improving fuel efficiency and increasing torque compared to 2007 technology.

What fuel saving can I expect from a truck equipped with Selective Catalytic Reduction (SCR) technology?

Selective Catalytic Reduction (SCR) is an after treatment emissions control technology, which deals with emissions outside of the engine. This means manufacturers are able to tune engines to boost performance and achieve fuel savings. The extent of these savings will vary, but fleets' experiences with post 2010 heavy-duty trucks suggests fuel savings of around 5% compared to 2007 models with similar engine specifications. PACCAR, Daimler and Cummins all use this figure in their 2010 model specs. Reports from customers using off-road machines with SCR are reporting fuel savings of 5% and higher.

This is comparing SCR vs other environmental crap. How about same engine with NO environmental crap on it?