WHAT IS AN EGR SYSTEM ?

        EGR stands for Exhaust Gas Recirculation. This system is fitted to most all modern combustion engines in an attempt to reduce the amount of emissions produced. The EGR system directs an amount of exhaust back into the cylinder in order to lower the combustion temperature which reduces the amount of Nitrogen Oxide (NOx) formed during combustion.

        Unfortunately the introduction of exhaust into the cylinder means that valuable Oxygen (O2) is now replaced by non-combustable matter. Oxygen is essential  to the combustion process - less oxygen means less combustion (less power, less efficiency).

      Adding Exhaust Gas to a diesel cylinder reduces the specific heat ratio of the combustion gases; this reduces the amount of power that can be developed by the power stroke. This also increases the amount of unburnt fuel in the cylinder which leads to an increase in particulate matter (carbon) in the exhaust.           These abrasive particulates then get re-introduced into the cylinder causing engine wear & oil contamination. The attempted solution to the particulates is a Particulate Filter (DPF in diesels) however this filter is usually placed in the tailpipe to lower only the measurable particulates exiting the tail pipe.

        The DPF in this location does nothing at all to reduce the damaging particulates in the engine intake, cylinder & oil.

        Another side effect of the EGR system is the mixing of the hot exhaust gas with the oil vapour from the rocker cover. The rocker cover is under vacuum in most modern engines in order to help bring oil up the top & lubricate the head components. This vapour gets sucked through the turbo, into the intercooler & into the intake where it mixes with the hot exhaust gas & coats the entire intake. The continual coatings form accumlating layers until the engine can no longer breath; this leads to a continual decrease in power until finally the engine chokes. Once this occurs the engine is ruined.