DIS

[Clay Buccellato (Anthony)]

> Date: Sat, 20 Nov 1999 09:42:57 PST
> From: "scott christensen" <scottchristensen at hotmail.com>
> Subject: DIS

> I am doing research to roll-my-own DIS for a 4 cylinder aircraft engine.  I
> would like to control the timing advance with a microcontroller based mainly
> on the MAP reading.  (in aircraft RPM's stay constant but MAP changes
> drastically with altitude variation)
> 
> A few questions for the group:
> 
> 1) I like this CDI multi-fire MSD-6A unit (~$130).  Is there a similar
>    unit that can control two different coils simultaneously for a four
>    cylinder engine, ala "waste-fire" style?

You can use two of them. Jacobs and MSD both make a 4-channel CDI unit
for waste-sparking an 8 cylinder. I think MSD and Crane make a 2-channel
unit for firing a four cylinder.

One downside to MSD, is their 6A series coil drivers are current
limited, and incapable of driving really hot, low impedance coils. If
you're assembling an ignition, you might as well get your money's worth,
so I'd recommend Jacobs or Crane.

> 2) I found this waste-fire coil picture here on efi332:
>      ftp://efi332.eng.ohio-state.edu/incoming/coil.jpg
>    Anybody know what this coil is from?  Specs?

Kinda looks like a factory coil. Jacobs makes a waste spark coil called
the MUCHO-I, that specs out alot better than the factory waste spark
units.
 
> 3) Anybody out there roll-their-own CDI coil driver circuitry?  (or
>    use the "capacitive discharge driver" circuit from Zublin's
>    MSD-6A article)

Why re-invent the wheel? They're not that expensive, and I'm sure your
time is worth something.

I can understand it, if nobody makes what you need. But, in the ignition
arena, we are better supported.
 
-Clay