I have been thinking a little bit about this issue. I would like to
add my 2 cents
and see what others (particularly Adkinson and Braly) have to say
about this issue.
I just had an IO-550N built for my Legacy and I specifically
requested dual magnetos. My reasons for requesting dual magnetos
were:
- Safety Reasons - continued spark even with electrical failure
- Maintenance Reasons - better parts availability, mechanics have
greater familiarity with magnetos
- No good evidence of improved horsepower with electronic
igntion
- Possible decrease in TBO with electronic ignition due to
unproven spark advance curve
Recently, I have been thinking about using the new E-Mag to replace one or
both of my magnetos. E-Mag expects to have their new 6 cylinder model out
shortly (I know - don't hold my breath). It has several features that
appeal to me:
- An internal generator that will continue to spark even with a complete
electrical failure
- The ability to be set to a fixed advanced curve like a Magneto
- Immunity to high altitude misfire (like a pressurized
magneto)
Some questions with respect to the additional spark advance provided by
electronic igntion:
- Has an increase in horsepower due to additional spark
advance been well demonstrated? (Same engine operated on a
dynamometer with and without electronic ignition)
- Even if horsepower is increased, does it come at the expense of a
decreased TBO? (Advanced timing can increase intra-cylinder
pressures)
D. Brunner
----- Original Message -----
Sent: Thursday, January 03, 2008 1:18 PM
Subject: [LML] One mag, One electronic ignition
> I have not done any tests but I believe if One Mag and One
Electronic
> Ignition is used you are likely to fail the Mag Coil
prematurely (that would
> reduce the aprox. 400 to 600 hour normal failure
of a new Slick to a really
> unacceptable life). Why?? One of
the principal advantages of EI is the
> variable timing advance that
improves power and efficiency. When the EI
> fires a plug before the
Mag, the pressure rise from earlier combustion may
> prevent the Mag plug
from firing. Maybe (probably?) preventing the Mag plug
> from firing
at least at higher altitudes where advance is the greatest. I
> base my
theory on the old Champion Spark Plug Testers that used an air hose
> to
increase pressure while firing a plug to check its ability to continue
to
> fire. What do others say?
>
>
> Steve
Colwell