The RX8 coils are the only coils on the market
 that will fire 9000 times a minute.

 The GM LS2 or LS3 or GM truck coils are only designed
 to fire 3500 times a minute at the most.
 Some are using them on the rotary and there is some
 evidence they start having trouble around 6500 to 7000 RPM.

 The reason for this  is the four stroke piston engine
 fires the plug every other revolution. So 7500
 RPM in a Corvette engine the plugs are only firing
 3550 times a minute. A rotary fires the plug every
 revolution. One reason they get so much power
 for the small size of the engine.

 I therefore conclude the RX8 coils are our best bet
 long term. Mazda had trouble with the early versions.
 Some early coils over heated and died killing the engine by
 washing off the apex seal oil with raw unburnt fuel.
 Poor Mazda had to increase the RX8 engine warranty to
 100,000 miles or eight years.

 I must say I am not surprised because Mazda was out
 there on the bleeding edge with a 9000 RPM
 red line and a rotary to boot. Law of unintended
 consequences.

 Mazda finally identified the problem and improved
 the coil (we think) about 2006 to 2007.

 Here is a heat sink that should add a bit of long term
 reliability.

 If you  are running a 2.85:1 gear box I recommend RX8 coils.

 Paul Lamar

Wait a minute, 9000RPM with an 8 cylinder engine is 72,000 sparks
 in two  revolutions. That is 36,000 sparks by the old coils per
 minute. One  coil per  plug with the Pertronix should work.

Dale Davies

 Wait a minute Dale and Paul.

 With an eight cylinder four cycle engine

 9000 Rev4 Sparks1 Min600 Sparks
 ------------ X ----------- X ------------ = ----------------
 1 MinRev  60 SecSec

 With a two rotor Wankel

 9000 Rev2 Sparks1 Min300 Sparks
 ------------ X ----------- X ------------ = ----------------
 1 MinRev  60 SecSec

 A two rotor Wankel is equivalent to a four cylinder piston engine
 not an eight cylinder piston engine as far as ignition system load
 is concerned.  As for power generated let's just say there's not
 much of a comparison there.

 If you only consider one piston against one rotor the one rotor will
 fire twice as often as the one cylinder.  It takes two cylinders to fire
 as often as one rotor.  If want to fire as often as an eight cylinder
 piston engine you will need four rotors.  I don't think many of us
 are considering a four rotor in our airplanes.

 If you have one coil/plug that coil will have to fire twice as often
 on a Wankel compared to a piston engine.  If you have a single coil
 and a distributor then a two rotor Wankel has the same demand on the
 coil as a four cylinder piston engine running at the same speed.

 You're both right about what you're saying.  You're just looking at
 it from two different perspectives.

 Mark LaPierre

Mark,

My point is that if a coil can fire that many times on a V8 engine, it should
live happily on a two rotor. One coil per plug or possibly one waste spark
coil for the leading plugs and individual coils for the trailing plugs. Fired
with the Pertronix CD ignition box; one per coil.

Dale Davies

Inductive or CD on the V8? One layer distributor or two layer
distributor. If inductive what is the dwell time?

Any coil will work with CD at high RPM.

BTW I just mounted the RX8 coils on the heat sink on the
engine and here are some pictures.


Paul Lamar