Air flow & such

[DRM]

OK... I've been reading this list for several weeks and am still not 
ready to "CLEP" for my degree in engineering, but the topics are getting 
closer.  I don't know about the American car systems but based on playing 
with Bosch L-Jet on a Alfa Race car...

The way I understand it, the flapper type AFM provides a bias voltage to 
the ECU (with a range of something like 1v. to 5v.) through a wiper 
resistor inside the AFM.  The ECU in turn controls injector period or 
duration based on air flow.  I have wanted to get rid of the restrictive 
flapper type in favor of the hot wire or film type used on the Motronic 
and others, but people are telling me, you can't because it's "Digital" 
and the L-jet is "Analog".  What is the difference between a "Digital 
volt" and an "Analog Volt", or did I miss something in Mr. Kelly's basic 
electronics course?  

On a roadrace car, that spends most of it's time (hopefully) with the 
throttle either wide open or completely closed, how critical is the 
measurement at part throttle in this application.  BTW, when opening the 
throttle fully from idle on the Alfa, you can hear the flapper SLAM open. 
 Does it close back partially after the initial change in pressure and 
follow rpm with load, or does it remain open?  If it remains open, then 
it must only have a linear effect under part throttle acceleration, which 
we try to avoid on the race track.  
	I'm not done, but that's enough for now.  Be gentle, it's my 
first time.


Dave Miller <dmiller at totcon.com> Deltona, Florida USA