design TBI for older engine??

[Tom Cloud]

        [ snip ]

>What I want is a controller which will handle a Ford throttle body with IAC,
>preferably the single barrel from a Tempo/Topaz using inputs for coolant
>temp, air temp, throttle position, MAP, O2 and possibly vehicle speed.  I
>might like to incorporate ignition control at some time with a knock sensor,
>but that isn't necessary.  
>
>I guess that what I'm looking for will end up being a lot like the Holley
>Projection, but with more use of OEM parts like the throttle body, better
>adaptablility to my engine, and more tuneability.

        [ snip ]

that's my interest too.  I have the ProJection.  It's limited
(it's not the digital), but very functional.  What I've learned
from it and the gurus on the list, is that lots of those inputs
aren't needed.  They're way up there on the "point of diminishing
returns" graph and, unless you're trying to maintain emissions,
not needed.

The ProJection uses only RPM and TPS.  It uses TEMP for the
choke relay function (don't know if they actually enrichen
during this time or not).  Deduce from that that RPM and TPS
are the major data points to consider.  MAP and EGO (probably
in that order) would be next.  My whole contention has been
that one should consider the cost and effort versus the
benefit returned.  Clearly, you can't run without RPM
or TPS (can you?).  MAP and EGO just help you more accurately
determine the engine's operating status.  The others ????
I think they're mostly for emissions and provide little
benefit for the effort and expense of implementing them.

Tom Cloud <cloud at peaches.ph.utexas.edu>