Differences between automotive & airplane engines

Your points are well taken. The cost of just replacing the O2 sensor
is not
exorbitant.

Is there any really easy way to tell what engines are available with
non O2
sensing ECMs?


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I would assume any engine that is marketed to a foreign country that
doesn't require the use of unleaded fuel would be compatable. I know
for sure the GM LS1 series are available with both style puters, I
think the Caddy northstar engine comes that way too. There are
companies that manufactuer "test" units that mimic O2 sensors so that
is an option. On my Firewall forward package I kept things VERY simple.
One Holley carb with the Mcneilly mixture leaning block installed gives
precise fuel metering, is cost effective and bulletproof. In my
application I have a high wing so if by a million to one shot I lose
both fuel pumps ,gravity flow should keep the motor running till I get
her down safely. My ignition system consists of dual MSD boxes,one fed
throught the main buss and the other fed straight from the battery. I
run a Optima gel cell unit that has 950 cca and can deliver enough
voltage to run the ign for hours. The DAR that inspected my plane asked
that very question and together we calculed I would have to land three
times for fuel before the ign would fail from low voltage. I would like
to think I am not dumb enough to take off the second time in that
failure mode. G

Ben
www.haaspowerair.com

My ignition system consists of dual MSD boxes,one fed
throught the main buss and the other fed straight from the battery. I
run a Optima gel cell unit that has 950 cca and can deliver enough
voltage to run the ign for hours. The DAR that inspected my plane asked
that very question and together we calculed I would have to land three
times for fuel before the ign would fail from low voltage. I would like
to think I am not dumb enough to take off the second time in that
failure mode. G

Ben
www.haaspowerair.com


Ben
Your ignition that is "fed straight from the battery." is it straight or do
you have a high current isolation diode in there (and hopefully fused!)?
If not it could fail and take down the battery/alternator and main buss
also.
John
Just curious, no flames ;-)

John wrote:
My ignition system consists of dual MSD boxes,one fed
throught the main buss and the other fed straight from the battery. I
run a Optima gel cell unit that has 950 cca and can deliver enough
voltage to run the ign for hours. The DAR that inspected my plane asked
that very question and together we calculed I would have to land three
times for fuel before the ign would fail from low voltage. I would like
to think I am not dumb enough to take off the second time in that
failure mode. G

Ben
www.haaspowerair.com


Ben
Your ignition that is "fed straight from the battery." is it straight or do
you have a high current isolation diode in there (and hopefully fused!)?
If not it could fail and take down the battery/alternator and main buss
also.
John
Just curious, no flames ;-)


Yes to the later of the above.................................

("stol" wrote)
My ignition system consists of dual MSD boxes,one fed throught the main
buss and the other fed straight from the battery. I run a Optima gel cell
unit that has 950 cca and can deliver enough voltage to run the ign for
hours.


Ignoring paperwork issues for the moment: Is this an ignition system that
could be easily(?) retrofitted to a standard Cessna 172 / Piper Warrior?

If yes, (guesstimating) what would the performance gains be over the factory
stock ignition systems they're running now? 1%? 5%? 10%?

Or is it mostly a reliability issue?


Montblack

Ignoring paperwork issues for the moment: Is this an ignition system
that
could be easily(?) retrofitted to a standard Cessna 172 / Piper
Warrior?

If yes, (guesstimating) what would the performance gains be over the
factory
stock ignition systems they're running now? 1%? 5%? 10%?


Or is it mostly a reliability issue?


Montblack


//////////////////////////////////
It is VERY reliable for sure. If I were to"experiment" with this
concept all one would have to do is install a crank trigger to fire the
boxes, have it set up so the plugs would fire every 360 degrees as to
keep the distributing simple, who cares if the plugs spark during the
overlap period, Two strokes do this. The MSD units can be fitted with
timing curves so that will give a performance gain for sure. As for
amount of HP gain, if I were younger and still had my R&D dyno I sold
to Jasper engines a few years back I would experiment just to see what
numbers would come up. My gut feeling is................8-12%

Ignoring paperwork issues for the moment: Is this an ignition system that
could be easily(?) retrofitted to a standard Cessna 172 / Piper Warrior?

Here's something to ease the paperwork issues:

http://www.unisonindustries.com/prod...ains_menu.html

This system varies the timing on certified aircraft engines,
but does not advance timing beyond the setting specified by the engine
manufacturere. I don't know if this is because there are no gains to be
had (25 degrees BTDC on an O-320, for example, should be plenty for
2700 RPM), or if the engine's TC would prohibit it. They do claim
better performance at any power setting below max, though, and smoother
operation.

Dan