Quote:
Originally Posted by LodiWino
Is an idle air control necessary on a stack injection set-up?
Rather than plumb a runner from each stack to a plenum for the IAC, could you set the idle ignition map to retard the spark?
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You can accomplish timing-related regulation of Idle speed with many of the aftermarket EFI controllers. For example, the FAST XFI system can vary the iginition timing to control small errors (a few hundred RPM tops) in idle speed. Remember that that IAC does other things than just regulate idle. It is also used, for example, for dashpot functions (i.e. providing a soft landing when you slam the throttle shut at high speed). The IAC setups on TWM intakes seem to work pretty good for small block applications up to maybe 427 ci. For the really big FE motors, its hard to provide plugmbing big enough to allow the IAc to fully regulate idle. I have an IAC setup on a 482 ci FE motor with a TWM intake. The setup can raise idle speed from the target 850 PRM when the motor is warm to about 1100-1200 when the motor is cold. This is a bit marginal but still helpful when warming the motor when its cold.