Optimizing A/F Mixture & Quality

[Shane Moseley]

Since there has been some recent talk about Air/Fuel ratios, Heat/Energy
content of various fuels/additives, & other fuel delivery related
topics, I would like to get some opinions on the following:

1. Re: Optimum A/F ratios

  I understand that most O2 sensors have a fairly narrow band of
operation and give primarily indications of 'too rich' or 'too lean'.  I
assume that for this reason, they are used mostly (some say always) at
either idle or cruise.  Most agree that they are useless at WOT & part
throttle (agrees w/earlier assumption).  A recent post in one of these
lists mentioned a new spin-off of Fel-Pro called FP Performance that has
a computer-controlled FI setup with a wide-range O2 sensor (high dollar
option?) that can sense a 12.5 (or whatever the optimum WOT A/F is).  If
this is so - then wouldn't it be best to be in closed loop almost
always? (after engine has reached operating temp of course)  Anyone with
experience here?  I was thinking seriously about running down to
Ashland, MS (home of FP Performance & about 40 min drive from Memphis
8-) and insisting they hire me on.

2. Re: Optimum conversion of fuels potential for energy (combustion)

After being intrigued for many years about engine intake designs -
nothing mixes up conversation better than Smokey Yunick (& other
Otto-cycle designs) and his miracle engines that got 50-60 mpg with no
performance loss (40% gains instead 8-) by HEATING the incoming A/F
mixture to around 400 degrees.  Most say 'yeah right - then why are the
factories all producing intercoolers?'  Well, I have read many of
Smokey's articles and have the one with the design drawings of his Fiero
experiment in Hot Rod June '84.  I understand that internal combustion
engines probably average around 25% efficiency of converting fuels
potential for energy (BTU's?) into actual usable energy (read flywheel
horsepower).  And that current designs might be between 30-40 percent in
optimum conditions (read hardly ever).  Seems to be alot of room for
improvement here!  This is the basis for Smokey's design.  Further -
according to several sources (nice one at
http://www.autoshop-online.com/auto101/fuel1.html about all sorts of
things including description of operation of Chrysler X-Ram intakes) the
optimum condition of the incoming mixture are something like:

"Dry fuel vapor is an ideal form of fuel charge, but present-day fuel
prevents this unless the mixture is subjected to high temperature."

Attempts to achieve a greater conversion rate (efficiency) are commonly
known as supercharging & turbocharging that 'pump up' the incoming
mixture causing a side effect (cant remember exact mixture
condition/problem) thus the need for intercoolers (say what?
contradiction?), additives, etc. for correction.

Seems kinda confusing I know - Why not skip the whole mechanical attempt
at regulating all these variables and let a computer control all
(especially temperature/condition of incoming mixture) for an optimum
(under all conditions 8-) conversion/combustion/BURN!

Comments welcome!


"We have the technology... We can build it..."


-- 
Shane Moseley    Home: http://www.netcom.com/~smoseley
Systems Analyst  Work: http://www.healthsphere.com
'96 Indy Ram     Play:
http://www.geocities.com/MotorCity/3067/indyram.html
'74 Challenger  <- 2 360 engines (magnum & non) 245hp each dying for
flog time!