Differences between automotive & airplane engines

"stol" wrote in message
ups.com...
On the related, though not identical, automotive conversion issue; I am

comming around to a hypothesis that the complete ECM and sensor package
of
an unmodified automotive engine may be useable with leaded fuel. I
mention
this because the ECM systems in automobiles and trucks to a commendable
job
of managing mixture under a wide range of conditions.


My reasoning is that the higher average power levels in aircraft use
may
keep the oxigen sensors in the exhaust system hot enough for the
inevitable
lead deposits to sublimate off as fast as they would otherwise build.
My
best guess is that average power levels in automotive use run around
10% of
maximum, due to a lot of time spent idling


////////////////////////////////////////////////////////////////////////
Alot of ECM controlled motors have optional ECMs for "offshore" markets
and those don't use a O2 sensor. The LS1 Gm motor can be bought with
the US puter or the "offshore" one. The offshore one doesn't need
Oxygen info to run properly. I agree the high output of a aircraft
engine will burn off alot of the lead plating that happens on a O2
sensor but it still will lose value and give the ECM a bad reading
after a 100 hours or so. Ya just make it a givin that during every
annual ,oops, conditional inspection you just replace the O2 sensor
with a new one and toss out the old one. They are less then 45 bucks.
That equates to about 1.78 Faa approved certified spakplugs...

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?

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?


////////////////////////////////////////////////////////////////////////

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

Yea...all of them.

The OBD-2 standard, which all cars sold in the US have had to meet since
1996, demands that if the O2 sensor goes bad, the "limp home" or "open loop"
mode (in other words just what you want) must be good enough to not only run
fine, but it's gotta still pass the smog check (750 PPM In my state).

If your computer has a "closed loop" mode, great, but there is no advantage
to insisting on a computer that CAN'T use an O2 sensor if one's available.

Just put some black electrical tape over the "check engine" light and you're
as good as if you'd spent $2K on an aftermarket ECU!


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

"Ron Webb" wrote in message
...

Yea...all of them.

The OBD-2 standard, which all cars sold in the US have had to meet since
1996, demands that if the O2 sensor goes bad, the "limp home" or "open
loop" mode (in other words just what you want) must be good enough to not
only run fine, but it's gotta still pass the smog check (750 PPM In my
state).

OBD-II requires you to set a code and turn on a light. It does not require
any kind of performance once the failure has been detected. On the other
hand, I don't know about EVERY brand, but the ones I work on will run just
fine with the O2 sensor disconnected. We try very hard to make sure you can
make it home in the event of just about any sensor failure.


If your computer has a "closed loop" mode, great, but there is no
advantage to insisting on a computer that CAN'T use an O2 sensor if one's
available.

Just put some black electrical tape over the "check engine" light and
you're as good as if you'd spent $2K on an aftermarket ECU!

Yea, the bulb takes a LONG time to burn out on it's own.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader.

"Peter Dohm" wrote in message
...


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

Yes, just visit a dealer in Saudi Arabia and see what they sell.

:-)

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader.