Honda Direct Fire Coils

[James Ballenger]

	It does seem that Honda is using them in a waste spark setup,but this seems
odd to me because of the following.  The waste spark coils will charge and
fire most of the voltage on the side with higher resistance (compression) in
theory.  Therefore most of the voltage will go to the firing cylinder and
will be used towards combustion.  If you charge up 2 coils at the same time
for 2 cylinders, they will both fire fully and will therefore have a full
spark a few degrees ahead of the intake stroke on the second cylinder.  It
seems that firing fully on both (CNP) instead of firing partially (waste
spark) would be an unnecessary draw.  Lemme know if this makes any sense ;-)

James Ballenger

>-----Original Message-----
>From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
>Behalf Of Eric Bryant
>Sent: Thursday, February 22, 2001 8:37 AM
>To: 'diy_efi at diy-efi.org'
>Subject: RE: Honda Direct Fire Coils
>
>
>Other than issues with not being able to fully saturate the
>coil, I don't
>see a problem with firing them as a waste-spark setup.  I'm sure Honda
>designed the coils and drivers to be used this way.  I'm not
>aware of any
>motorcycles that use a cam sensor in a non-EFI application
>(there may be
>some; I just haven't seen them).  You might want to look at
>the Yamaha R6,
>since that also runs CNP in a carbureted application.
>
>My Suzuki TL1000R uses a cam sensor to fire each plug only on
>the combustion
>stroke, but it can run without the cam sensor as a waste-fire
>setup.  I'm
>not sure what effect this has on spark intensity at high revs, since I
>haven't done any dyno pulls in any limp-home modes:)
>
>Eric Bryant
>mailto:bryante at ghsp.com
>http://www.novagate.com/~bryante
>
>
>
>-----Original Message-----
>From: James Ballenger [mailto:vtjballeng at yifan.net]
>Sent: Thursday, February 22, 2001 1:31 AM
>To: diy_efi at diy-efi.org
>Subject: RE: Honda Direct Fire Coils
>
>
>    Honda did something similar on some new bike engines and
>these rev to
>14,100 rpm.  The problem I ran into with my Haltech E6S is
>that I only had
>two outputs to control ignition which would be very
>inefficient with these
>coils because two would fully fire at each tdc and could cause
>problems.  If
>you have 4 dedicated outputs and have a cam sensor you can run
>them but they
>are expensive and by design less powerful than the large coils of units
>outside the head.  The cool factor is extremely high though ;-)  I just
>realized though that the 99' F4 runs coil per plug and they have no cam
>sensor... hmmm.
>
>http://planeta.clix.pt/cbr600f4/pics/600f4-12.jpg
>http://planeta.clix.pt/cbr600f4/pics/600f4-25.jpg
>
>James Ballenger
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