quote:Dan Jones mentioned that there is software that blends MAP and throttle position.The reason being that neither system was optimum for either economy or performance alone.
There are probably others but Dan was referring to the Electromotive ECU (we bought ours at the same time). It has a blend mode that allows you to assign authority to the various sensors inputs (i.e. MAP and TPS for example). In IR EFI, this has benefit because manifold vacuum goes to ambient pressure very early in throttle rotation. This makes the MAP only useful for idle/low speed signal and atmospheric pressure correction. Some people people favor teeing a line from each cylinder to small plenums and vary the orifice and plenum size to tune. It's difficult to make such a signal correlate to anything meaningful. I think the blended mode is a better solution.
quote:If that is so, with an IRFI system, what would be the best to consider for ignition? Would a mechanical advance distributor now be obsolete?
You could still run any distributor you want independent of the EFI but as ROVERLTD mentioned, most of the modern electronic ignitions can receive siganl from ECU. If you spent the bucks on an ECU why not buy a distributor that allows you infinite control of your ignition MAPS. And, yes, you can prescribe any ignition MAP you desire and also have modified MAPS that are driven off input from coolant (and other) sensors for good cold and hot starting. All at your finger tips through your laptop. It's great. I bought the EM direct fire coil packs and went crank triggered. All I have in the distributor hole is an MSD plug to drive the oil pump and a cam sync sensor on top so I can go full sequential injection.
Kelly