IAC

[James Boughton]

Tom,
	This is a valid point.  If the Holley ProJection is a throttle
position based system you will not be adding extra fuel when
you add the extra air by bypassing the throttle plates.  You could calibrate
the setup to run rich at idle and then the extra airflow won't lean the engine
out past stoich.
	This is assuming I understand what you have posted about the Holley
ProJection system you have.  Just something to keep in mind.
	By the way, the OEMs get by this by either using MAP or MAF.  On
a MAP system the increased airflow will cause a MAP increase which in turn
adds more fuel (not quite this simple, but good enough for this discussion), and
on a MAF system, well, this is kind of obvious!  Believe it or not there are also
some systems that supply transient fueling when the IAC is changing position.

Jim Boughton
jpb01 at ibm.net

----------
> From: Squash <mpc at genevaonline.com>
> To: diy_efi at efi332.eng.ohio-state.edu
> Subject: Re: IAC
> Date: Monday, December 08, 1997 12:50 PM
> 
> Ok, here's the big question:  Why do you need 3 rpm levels?  Howz about
> just normal idle and high-idle, such as 1400 rpm to keep the alternator
> chargin' good for winching, etc?  I would look for a plug in your intake
> manifold and try unscrewing it and holding your finger over the hole to
> see if you can actually vary the engine speed that way.  I know that
> unless that plug is close to the center, the engine will not really
> increase in speed, but it will run kinda crummy.  but I would try it out
> first!  
> -- 
> Andy Quaas