There are only two reasons for you to keep it: if your legislation requires it, or the emmissions require it.
Blank it off (to bluff casual inspection) or remove all the bits. The diesel definitely runs better without it.
Personally, I think your second reason is the important one - not for emissions reg's, but rather the emissions themselves. Taking off a pollution control "for the sake of" is IMHO, environmentally irresponsible. IF EGR does in fact reduce the Nox in the emissions, isn't that a good thing? But to your last point, that does seem to be the case, and may in fact negate (my) reason two:
EGR systems have been used to reduce emissions of nitrogen oxides (NOx) from gasoline engines for almost 20 years. Basically, they work by recirculating exhaust gases back into the intake stream, which cools the combustion process and, thereby, reduces NOx formation. Because of tightening NOx standards, EGR systems are being developed for use in diesel engines, as well.
However, the application of EGR to diesel engines presents several challenges, including: insufficient differential pressure across the EGR line, which leads to a low flow rate of recirculated gases; contamination of the engine with particulate matter present in the exhaust; and increased emissions of unburned fuel components and particulate matter.
...particularly on older turbo diesels... Hmmm, need to read more on this. Do I sound confused?
Thanks for the input so far guys. <img src="/forums/images/graemlins/kewl.gif" alt="" />
