Not only was my RX8 coil discolored on the bottom.

    IT WAS DEAD!!!!!!!!!!!!!!!!!!!!!!!!!

    I could have lost the engine any minute.
    No indication what so ever that it was dead.
    No noticeable loss of power. Of course that
    was the trailing (top) plug.

    If the check engine light had come on I would have known
    about it but it did not!!!!!

    Minutes away from a new engine!!!!!!!!!!!!!!!!!

    Check those coils folks. I'll do it for you including
    shipping for $20 cash. All four. For a limited time
    only. Better yet get four new ones.
    Mine should be in in a day or so.

    Paul Lamar

    Paul...a Mazda service bulletin says that the discoloration on
    the bottom of the coils is normal and is not an indication of
    anything going bad.  One of the Mazda forums agrees with some of
    the messages saying that they have as much as 130,000 miles on
    discolored coils and testing showing no problems.  However, as
    you said, testing should be done after about 25,000 miles. Mazda
    suggests just a resistance test...attached is a copy of their
    service bulletin.

    Harley

    Thanks Harley for adding to the info on this.
    So far I have no less than 8 RX8 coils. I know my tester is working
    as some spark and some don't and I was very very careful about getting
    the drive to the coil right. The good old 50 cent CD 4050 does a
    masterful
    job of driving any transistor or FET. I have one RX8 coil that is
    bad with
    no discoloration.

    I will have a total of 12 shortly with the new ones coming from
    Pep Boys. Those too will be tested.

    In addition I can open and close the spark gap to measure the
    output voltage.

    I also have two running RX8 engines I can test them on.

    I have also noticed one other thing about them. They draw
    a huge amount of current during the 2 ms dwell time so make
    sure the ground and 12 volt wire is short and of high gage (18).

    I see from the Mazda service bulletin the trailing coil
    does not work during cranking. I wonder if Tracy implemented
    this feature? I also wonder why Mazda did that?

    Here is a simplified schematic of Tracy's EC2 to make it
    a bit easier to understand.

    I'll do one shortly for the RX8 coils.

    Paul Lamar

    I discovered the fact that the RX8 coils took such a surge
    current it was seriously affecting the 10 Amp 12 Volt power
    supply in my RX8 coil tester set up.
    The back EMF could kill the capacitors in the power supply
    so I replaced it with a motor cycle battery.

    snips.....


    Paul Lamar

    Check out this YouTube comparison of the LS1 & LS2 "Yukon" coils.
    http://video.google.com/videoplay?docid=-6218245369765754251#

    Mark

    Remember the V8 engine fires every other rev while
    the RX8 coils fire every rev. Not only that the RX8
    coil need to fire at 9000 RPM while the V8 6500 RPM.

    a 5 millisecond dwell is marginal for a rotary
    at 7500 RPM.

    My hopes are on the second gen RX8 coils.

    Paul Lamar
    --

Paul,

It is a good thing that I never run my engine that hard.  It rarely sees
above 7000, so the 585's ought to do the job.  As I recall, the Youtube
guy tested at less than 5ms with little change in output.  Anyway, the
585 coils are already on their way.  I'll let you know if I can detect
any improvement.

Mark

I have one and I will test it shortly. Got to get my RX8
back together today with the 2nd gen RX8 coils.

Paul Lamar