JaffaTheNeste wrote:

The chukka chukka- sound after shutting down means it is working properly. Cleaning cycle.

custom90steve wrote:

Or get a tune with EGR delete, then you fit a solid blank and that's it forever.

Whats the pros and cons of a EGR valve?....what do you lose or gain if you remove it?(not interested in sound effects )

nitram17 wrote:

Whats the pros and cons of a EGR valve?....what do you lose or gain if you remove it?(not interested in sound effects )

dgardel wrote:

Basically for reduce the NOx (generated by the temperature and NOT by the type of fuel).

On the gasoline engines NOx are trapped by the 3-way cat. Diesel engine (that uses 2-way cat because the temperatures are too low for a 3-way) need the EGR for reduce the NOx, but you reduce the O2 inside the combustion chamber (= less combustion efficiency).

So if you close the EGR (by ECU -contact Bell Auto Services here) the engine run a lot better with, yes, a little bit more NOx, but with low HC, CO and Particulate emissions.

AND, the EGR part of exhaust gas (with soot) ant the oil vapor recirculation produce a blck nud tha, during the miles, blocks the inlet manifold.




Click image to enlarge

If you want, try to remove the temp sensor on our Puma inlet manifold and see what......................

When combustion temperatures exceed 2500 degree F., atmospheric nitrogen begins to react with oxygen during combustion. The result is various compounds called nitrogen oxides (NOX), which play a major role in urban air pollution. To reduce the formation of NOX, combustion temperatures must be kept below the NOX threshold. This is done by recirculating a small amount of exhaust through the "exhaust gas recirculation," or EGR. valve.

In modern diesel engines, the EGR gas is cooled through a heat exchanger to allow the introduction of a greater mass of recirculated gas. Unlike SI engines, diesels are not limited by the need for a contiguous flamefront; furthermore, since diesels always operate with excess air, they benefit from EGR rates as high as 50% (at idle, where there is otherwise a very large amount of excess air) in controlling NOx emissions.

Since diesel engines are unthrottled, EGR does not lower throttling losses in the way that it does for SI engines (see above). However, exhaust gas (largely carbon dioxide and water vapour) has a higher specific heat than air, and so it still serves to lower peak combustion temperatures; this aids the diesel engine's efficiency by reduced heat rejection and dissociation. There are trade offs however. Adding EGR to a diesel reduces the specific heat ratio of the combustion gases in the power stroke. This reduces the amount of power that can be extracted by the piston. EGR also tends to reduce the amount of fuel burned in the power stroke. This is evident by the increase in particulate emissions that corresponds to an increase in EGR. Particulate matter (mainly carbon) that is not burned in the power stroke is wasted energy. Stricter regulations on particulate matter (PM) call for further emission controls to be introduced to compensate for the PM emissions introduced by EGR.

The most common is particulate filters in the exhaust system that result in reduced fuel efficiency. Since EGR increases the amount of PM that must be dealt with and reduces the exhaust gas temperatures and available oxygen these filters need to function properly to burn off soot, automakers have had to consider injecting fuel and air directly into the exhaust system to keep these filters from plugging up..


p.s. my Defender run from new with the EGR closed!!!! Now it has 83000kms