Holley Pro-Jection upgrade

[Tom Cloud]

>Hello all, Have been watching your site for a while now.  I really enjoy
>it.  Would like to join but not sure about getting so much mail.(Company
>box)  Anyway I have been debating on what I would like to do with my
>Projection Model 502-2.  They have a new Digital ECM upgrade but it
>still doesn't have the features that I would like.  I would like to at
>least add a MAP to it to help keep it running more consistant with
>environment changes.  I would like to use a MAF sensor if I could.  With
>the Ram Air boxes that you can find in any hot rod mag I don't think the
>plumbing would be too difficult.  I was thinking about GM ECM's.  Would
>I also have to add a crank trigger? Just for backround I am a systems
>tech. with over 5yrs exp. with loop selection, setup and tuning for
>temp. control loops, air flow control and pressure control, just to name
>a few. But I am just starting to learn about EFI. Perhaps I will join
>your list when I get my setup at home going.  
>
>
>                         Thanks!!!	
>			 Alan

Alan, I'm playing in a similar direction.  The alpha-n system
used in the 502 gives a lean condition at part acceleration
(i.e. before the POWER enrichment comes into play).  I'd like
to find out the particulars of the EGO feedback box sold by Holley,
but I know that it just intercepts the TPS signal and adds to
it.  I suspect that it doesn't subtract from it -- that way, the
POWER enrichment and any other setting you have that's richer
than stoich is unchanged.  That implies a simple op-amp summing
circuit with the input from the EGO being fed in only "positive".
I also would like to add the MAP though I think there most serious
weakness is what I've detailed here -- lean running at part
accel (until RPM catches up).

Holler at me if you've got any ideas.

Tom Cloud