just wondering in theory if it puts more unburned fuel back into the intake at idle to mild/part throttle there should be no performance decrease but could potentially be an increase in mpg?

I think this could work very well with big cams that have big overlap. thoughts? anyone ever tried this?

 

EGR lets burned exhaust into the intake to cool the combustion under cruise so that it can advance timing without getting knock and get you a little better mileage. If you have a big overlap cam, it kind of does the same thing due to reversion at low rpms.