There is a chip on the market that conditions the the stock Mazda crank angle
sensor in  all RX7's and RX8's to a simple 5 volt pulse that can be read
by any computer or ignition system. Works very well with CD systems
like MSD or the M&W oz ignition system.

http://www.mwignitions.com/pg_cdi_ignitions.php

Pro-14R    115mJ     10,500 RPM      Mazda twin rotor direct fire cdi

This is a very simple system to use. It fires the plug exactly when
it is told to fire. We use this system on TTC engine and it works very well
indeed.

The regular RX8 and Chevy coils take a computer with a complex program
 to fire as they must be turned on 4 ms before the plug fires no matter
the RPM. At 8000 RPM the plug must be fired at least once every
7.5 ms. At 4000 rpm it must be fired every 15 ms. In other words
the computer needs to know the rpm before it can decide when to
turn on the coil and then to turn it off to fire the plug.
A complex program indeed. We are talking one rotor here.

Tracy built that program into his system and had coil over heating problems
with the early versions. If you turn the coil on too long it will overheat
and fail. 4 or 5 ms max.

So to keep it simple use a Capacitor  Discharge Ignition system.

The chip that conditions the trigger pulse is the
LM1815 Adaptive Variable Reluctance Sensor Amplifier
Widely used by all car manufactures. Works with all Mazda sensors.
Puts out a nice square wave from the hash put out by the sensor.

Available at DigiKey or Mouser low cost.

The M&W system probably has this built in but the MSD systems
do not to my knowledge. BTW you would need 4 MSD systems
for one M&W so that will put the cost into perspective.

This is very important so save it as I will not be around for ever :-)

Paul Lamar


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