[Diy_efi] Electronic expertise requested

[Daniel R. Nicoson]

Phil,

I knew you had a sense of humor!

I'm actually considering three possibilities for powering my experimental:
1st choice-Ford 5.0 V-8, 2nd choice-Mazda Rotary 3rd choice-standard
Lycoming or Continental with standard carb-mag combination

1st Choice:  I happen to love the sound of my 1994 Mustang GT screaming
through 5,000 RPM.  Problem is it is not sane or legal to do that very often
except on a race track.  I have been tuning my Mustang since last summer
when I bolted on heads, cam, manifold, large injectors and a new MAF.  I
learned right away it didn't run very well.  After installing and learning
the EEC Tuner I have been very comfortable on what I can do with that
processor.  I use a permanently installed DIY-Wide Band oxygen sensor to
tune the high end and the data log from closed loop allows good control over
the low end in open loop.  The only thing I have trouble optimizing are the
spark tables.  I don't have a knock detector and I have only just started
learning about ion sensing (cool possibilities by the way).  So my spark is
probably far from optimized but I have experimented "by ear" to keep it from
pinging on 89 octane and the car is a blast for a daily driver.  For
aircraft application I probably would forgo the Ford EEC but not because of
emissions.  I can turn all that off and run open loop in the aircraft so
that leaded fuel isn't a problem.  I would be more likely to use two Simple
Digital Systems processors http://www.sdsefi.com/aircraft.html.  They are
less involved and they fly behind what they build.

2nd Choice:  The Rotary conversion is probably the best match to my
particular aircraft.  Size weight and power are perfectly matched.  Even
better yet the "guru" of this conversion is a retired electronics engineer
and has designed his own EFI with dual channels.  He has many hours on this
setup.  I could even use his system on my V-8.

3rd Choice:  Standard aircraft engines - just wouldn't be as fun...More
expensive too.

My original post was a valid question for any EFI system I choose if I go
with more than one system.  As far as other owners of standard aircraft
engines, I'm not kidding myself that my hobby will solve anything for the
rest.  99% of pilots don't really care what's under the hood as long as it
works reliably and they can still wear the big wrist watch!  I'm just
different and have to do this because it is there.

Thank you for your thoughts.

Dan

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Phil Hunter
Sent: Friday, June 20, 2003 12:42 PM
To: diy_efi at diy-efi.org
Subject: Re: [Diy_efi] Electronic expertise requested


> Phil,
>
> You're no fun!
Yep, dats me, Ol' StickInTheMud hisself.

Okay, so you know a heck of a LOT more than you let on, and I'm
sure you've forgotten more than I've ever known about aircraft
engines, but I don't see why you'd want to take something that
is basically designed for emissions control, and try to adapt it
to an environment of widely varying A/F mixtures, MAP's, IAT's,
etc.

Personally I'd focus on solving the problem(s) so all owners of
that aircraft could benefit. I know the ignition is shielded, but
might there be enough leakage that you could use a timing light
clamp (or a lot of wraps of wire) fed directly into a portable
o'scope to see if you're getting a misfire? What about putting a
"sugar cube" or "lipstick" CCD camera under the cowling somewhere
to look for errant sparks? Any place to monitor fuel pressure? Can
you "sacrifice" the exhaust manifold(s) and a few NB O2 sensors to
get an idea of whether the mixture is going too rich or too lean?
I know you can get spark plugs modified w/ tiny pressure sensors,
might be a more practical if not $pendy alternative to Ion Sensing.
Can you get Cessna or Lycoming to pay for any of that?

Considering that this is a public, archived email list, for
liability reasons that's all I'm willing to say here, but I may
send some more thunks privately.

As an aside, last night I attended a job related presentation about
"how my experience as a private pilot made me a better systems
administrator" One of the key points was "beware of automation" and
unintended consequences, citing Bonanza's automatic landing gear as
an example.

rgds,
Ol' StickInTheMud
(digest)

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