Not enough sparks per combustion event :)
  First cost would be lower but one might make it up
  long term with a dual or triple MSD.
  Paul Lamar
 ---------------------------------------------------
  Paul,
  Couldn't the Ford EDIS be fed into an MSD ignition module to
  produce a multi-spark ignition system?
  Mark S.
  Yes but you don't need it. Just three low cost ABS sensors in the
  three rotor case with one just tit on the trigger wheel will do
  the job.
  In Tracy's system if it puts out 3 pulses to fire the LS1 coil
  that can be conditioned to fire 3 MSD systems.
  Paul Lamar
 ---------------------------------------------- Paul,
  Sorry, in my last post I was thinking of an automotive
  application rather than a/c.
  I've been re-reading your information on your 220v inverter multi-
  spark ignition system. That would be a big improvement over the
  single-spark LS1 approach.
  Mark S.

 --------------------------------------------------------------------
  You may have missed it but MSD rated the multi spark at 3000 RPM limit
  with an 8 cylinder, 6000 with a 4 cylinder and 12,000 RPM with
  a 2 cylinder or one cylinder 2 stroke or a one rotor. All firing
  once per rev.


 Quote:
  Dear Sir:
  After conferring with the engineer I transferred you to yesterday,
  I was  opposite of where I needed to be.
  He explained that he actually hooked up a 6A unit, basic CD ignition
  with no rev. limiter or cylinder select function. On an 8 cylinder
  application the multi-spark reduced to one spark at 3,000rpm.
  When he tested for the 4 cylinder application the multi-spark
  doubled to  6,000.
  He surmised that on a 2 cylinder application, the multi-spark
  would  disappear at double that r 12000 rpm.
  This was on a four stoke application.
  He did say that he wasn't sure about a Wankel application and was
  waiting for a call from you to discuss some issues.
  That engineers name is Rick Bennett, his extension is: 2402
  Sorry for the confusion. I apologize.
  Thanks,
  Rick Jage MSD Tech
  end quote
  --------------------------------------------------------
  My system would work better as the sparks are more widely spaced
  but three MDS units one for each rotor is almost as good.
  http://www.rotaryeng.net/Why-CDI.html
  Paul Lamar
 -----------------------------------------------------------------

  Paul,
  So then, for a 3-rotor, using six individual MSD-6A modules would
  provide  a multi-spark ignition good for up to 12k rpm. As the MSD-
  6A weighs 3 lbs  each, that would be 18 lbs. of added weight not
  counting the coils. I'm  curious if its possible to use one MSD-6A
  per rotor to fire a dual tower
  (wasted spark) coil to fire both the leading and trailing plugs
  on the  same  rotor? Probably not.
  Mark S.
 ------------------------------------------------------
  You got me there Mark. I think Lyn Hanover mentioned that.
  Yes here it is:
  quote:
  "The top pick up for the front housing and the lower pick up for
  the rear housing. Have the MSD drive a double ended MSD (or other
  suitable) coil to fire both plugs at once. No advance curve is
  required. The engine will start and run fine with
  anything from 20 to 27 degrees of advance."
  end of quote.
  -----------------------------------------------------
  That 220 volt power supply weighs only 2 pounds so my system
  would be lighter in weight. Less the coils of course.
  Paul Lamar

 -------------------------------------------------------
  I see that it was Lynn's quote. But reading it a few
  times, it appears that he's describing a wasted spark system. I
  am wondering if one dual-tower coil (fired by an MSD) can fire both
  plugs on the same rotor. That's how I ran my 3-rotor on test stand,
  but didn't have any way to tell if both plugs actually fired
  together or not. I would need a scope to tell for sure.
  Mark S.
 ---------------------------------------------------

  Not wasted spark. Both upper and lower plugs fire
  at the same time but only on the rotor that is ready.
  Paul Lamar
 -------------------------------------------------------
  I trust Lynn's information. If he says it will work, then it will work.

  I could use my triple pickup CAS. (I still need to look around in
  my parts bin for it.) I know it will work for triggering the three
  MSD-6A's because I ran it years ago using three GM ignition modules
  and three GM (Buick) dual tower coils. The only difference here is
  that I would substitute three MSD-6A's for the three GM ignition
  modules. And as Lynn suggests, use three MSD coils.

  Firing only one rotor each, the MSD's shouldn't have any problem providing
  multiple sparks up to max rpm (7500).

  Mark S.
 --------------------------------------------------------------------
  How well will these coils stand up when they are firing two plugs in the
  compressed mixture. With two gaps full of air molecules that are
 resistors,
  the firing voltage will be higher. In an a/c application at cruise, the
  continuous load over hours should heat the coils up and reduce life
  expectancy. In a race car, there is short bursts of full throttle and then
  Deceleration. This allows some cooling.

  Dale Davies
 -------------------------------------------------------------------------
  Good question but the second gen double output coil held up real well in
 AC
  use and they can be used with MSD systems. Just the ballast resistor
 burned
  out in aircraft use. Actually a cap discharge system is easier
  on the coils. You can unbolt and disconnect them from the 2nd gen igniters
  and used them as CD coils. No ballast resistors.

  If you can get them on e-bay for a good price snap them up.

  Paul Lamar
 ---------------------------------------------------------------------
  Paul,

 Last week I decided to move ahead with the MSD cap discharge ignition idea
 for my 3-rotor. I purchased three MSD-6A ignition modules. The three 6A's
 will be driving one dual tower coil each (one 6A / coil per rotor). The
 three MSD's will be triggered by a custom CAS with one trigger per MSD-6A.
  That should give me multi-spark to 12,000 rpm. ;-) I've hooked it up on
 the bench and it looks like it will work as intended. Just for
 clarification, this will not be a wasted-spark system. Each dual tower coil
 will be firing two plugs on the same rotor, as Lynn described. Stay
 tuned...

 Mark S.

 Do the MSD-6A really weigh 3 pounds each? The Mazda 2nd gen coil is 1.5
 pounds.

 Paul Lamar

--------------------------------------------------------

 Paul,


From the MSD spec sheet...

Spark Energy:105-115 mJ per spark Primary Voltage:450-480 Volts Secondary
Voltage:45,000 Volts Spark Series Duration:20 degree Crankshaft Rotation RPM
Range:15,000 RPM with 14.4 Volts Voltage Required:12-18 Volts, Negative
Ground Current Draw:1 Amp per 1,000 RPM Weight and Size 3 lbs.,8"L x 3.5"W x
2.25"H

It is interesting that the primary voltage is 450 - 480v.  DON'T TOUCH!!!

Mark S.

-------------------------------------------------------------------

It is just a narrow pulse a few micro seconds wide. I am not sure what
it would feel like but I am not about to find out :) They have about
150 to 200 volts over my system :)

http://www.rotaryeng.net/Why-CDI.html

Here is the preliminary coil driver circuit.
These circuits act like double pole solid state switches. When the
trigger comes in from one of the crank angle sensors the circuit
disconnects the main high voltage power supply and dumps the
charged 2 Mfd capacitor through the stock Mazda ignition coil.
Then it closes again to recharge the capacitor for the next time.
The upper FET turns off when each capacitor is discharged so the
power supply can continue to charge the other capacitors.


Rick Jage, You guys can have the idea for free. Please forward this message
to the engineer.

Paul Lamar