I just updated the simple and cheap 555 EFI system
 on the web site. We hope to test it this coming year
 on a RX8 P-port engine I have installed on Milo's
 test stand.

 http://www.rotaryeng.net/simple-cheap-555.html

---------------------------------------------------


BTW the apex seal oil hole pressure taps give a much more
uniform manifold pressure readings so the 555 system should
work pretty well. An unintended favorably confluence of
technologies :)

-------------------------------------------

I woke up this morning with another idea for the 555 EFI system.
One needs to enrich an engine for starting and how I was
going to do that was festering in my subconscious.

All one needs to do is open the throttle, set the leaning knob
to full rich and hit the starter button. With this system the
mixture ratio is directly proportional to the pressure of the
air mass getting in the engine. When the air pressure in the
engine is atmospheric which happens at WOT the mixture is full rich.

With my O-470 I must prime the engine and just crack the throttle
because the carb venturi injects only as much fuel as the air
flowing into the engine. Basically it is a mass air flow sensor
and this system is a manifold pressure system.

This system could wind up being cheaper than the $500 2 barrel Holley
500 CFM carb.

Dirt simple.  If this is not clear ask me questions.

Paul Lamar