Managing EGR for MPG

[DRW]

Yes, my car is OBD1 and it has a vacuum actuated EGR valve. The vacuum is metered through a solenoid which is controlled by the ecu. On my car the EGR port dumps into the manifold through one port just behind the throttle body plate. I suppose the engineers thought there would be enough turbulence in that area to evenly mix the exhaust gasses with fresh air.

To cool EGR I doubt it'll require an intercooler. The passage is about 1" round, so there isn't much volume to cool. I was thinking about using a small oil cooler, maybe a two row power steering oil cooler. I'll see what I can find in the junkyard tomorow.

I had another look into the ecu disassembly and found the EGR map for the auto tranny version of my car. It's slightly different, most notable is the minimum value of 3B. I suppose this is the lower limit that the engineers felt safe using. I think I'll make some changes and see what happens.

FYI the ecu code uses hexidecimal numbers which uses a base of 16, so to count in hex it goes like this:
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F,
10, 11, 12...1A, 1B, 1C, 1D, 1E, 1F,
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