Q Regarding EGR/Engine Performance/Tuning

[Crazy_pilot]

This sort of popped into my head the other day, maybe you guys who have looked into the engine's software can help me out here.

An EGR system basically siphons off a small portion of the exhaust gases and circulates them back into the engine intake, with the whole goal of reducing emissions of Nitrogen Oxide, with a few potential side benefits. When I took a look at the EGR system on the EG33 I got to wondering just how it applies and how well it was factored into the engine's software.

If you take a look at the system, you'll see it only works with the #5 cylinder (rear passenger side). The pickup is off the exhaust manifold, just after the #5 exhaust port, before the pipes have merged, and the dump is into the intake manifold, just before the #5 injector stack. This to me basically indicates that cylinder #5 is going to be developing less power than the other 5, because it has less oxygen coming into it. However, does the engine's computer know this? In a nutshell, are the injectors compensating for there being less burn-able air in that specific cylinder, or are all 6 injectors working at the same duty rate? If they're all the same, then that cylinder will be running relatively rich (less air, same fuel), and the others a bit lean (same fuel, but perhaps a bit more air than expected).

I don't know if finely tuning (with a Hydra probably) for this would have much of an effect on HP and performance levels, since EGR's are usually closed under load, but maybe during daily driving it would have a small effect. (mileage mostly). This is more to stop my own head scratching than anything else.