i was working on the 00vi today and after seeing the egr and aftermarket headers for the vq30 i noticed that the egr only reaches to cyl 3...? is it because it in the back and between 2 other cyls therefore making it the hottest and more prone to nox emissions?

why not cyl 4 as well or all cylinders for that matter? doesn't everyone of them get hot enough to produce nox?

 

The EGR is pulling exhaust gasses FROM #3, and putting it IN the intake. ALL the cylinders then get the exhaust gasses via the intake plenum.