I hade the 7747 ecm in car and old 350 with no egr pas (del egr in prom)didenth get *** fulemileage toth it was for that i hade no vvs.
Now a have 6395 ecm lo5 and when i did the wiring to fit my car i deleted the egr wiring (eng,trans,steringkolum,gauges,fusebox and wiring hardnes from 94 van).headders.open element. compcam XE250H-10.
Is it a BIG MISSTAKE.
Cant you get same fulemileage without egr or reconnet the egr wiring(a lot harder).

 

I was never able to document any increase in MPG using EGR. Maybe someone has, but not for anything I've worked on.

 

i noticed a little increase in fuel mileage with my EGR working, probably because i am a bit more agressive with highway mode with EGR than without EGR.

 

How many production cars still use EGR? I'm not being cynical, just don't pay much attention to it and really don't know. Maybe if it's not many, then it's not really beneficial enough for fuel economy.

 

im not sure just how many new cars still use EGR, fewer now than 10 years ago, but because of tighter emissions standards that may change again in the future. EGR is for emissions.

in highway mode i only went to 15.2~15.4 to 1 without EGR, with EGR im at 15.9~16.0. i have also added an additional 2 degrees of timing, im not sure if the added timing has helped my mileage any yet or not, but it seems to have helped part throttle response.

 

Virtually all production engines have some form of "EGR" even if there isn't a valve located somewhere on the intake. This can be achieved by a traditional EGR valve, cam phasing or by overlap incorporated into the camshaft grind. The goal with EGR is to keep combustion temperatures down to reduce NOx. The fuel savings is secondary (if it exists at all). Like so many things that can be done to a powertrain, there's a "sweet spot" of sorts where this will be more efficient which will need to be tuned correctly. If you seldom (or never) spend time in that spot *or* if the ECM isn't programmed to take full advantage, you won't see an improvement.