In theory, the EGR system reduces NOx at the expense of soot, power and fuel economy. You should notice less smoke with it defeated...assuming any smoke was visible to begin with. Your cylinder temperatures will be higher during the times when the valve would ordinarily be open, but peak temperatures during full load operation will be unaffected since the valve would be closed under those circumstances anyway.
The EGR valve isn't just an "open or closed" design. It is "mapped", just like your fuel maps. The ECU is able to open the valve a little or a lot, or anywhere in-between, depending on a complicated set of parameters.
The Device, however, is "all or nothing." That is bound to have some kooky effects.
I believe what we REALLY need is a circuit that varies the amount of resistance in the MAF wire depending on the "strength" of the voltage coming from the EGR control circuit.
-mickey
p.s. As for emissions: You are, of course, operating your vehicle STRICTLY off the public highways, so there is no legal issue here. (Right?)
It's a matter of choosing your poison. Do you like soot, or NOx? Neither is particularly good for the environment. NOx is probably worse, though, and it's been shown that disconnecting the EGR increases NOx output by a factor of TEN! That's a lot. I don't know how much difference it makes in soot output. And, of course, there is the long term effect of the EGR on your intake system and the overall efficiency and emissions output of your engine to think about.
[ June 05, 2001: Message edited by: mickey ]
