Subject: RX8 coil pulse length and voltage.
From: Rotary Engine
Date: 9/10/2006, 9:22 PM
To: AA-me


>> >     OK Paul
>> >     It might be a few days. Don't forget the pulse length and voltage. >> > I
>> >     am not
>> >     going to fly again until it is sorted. Local Mazda say that there
>> >     has never
>> >     been a failure of the igniters. I think the testers may have tried
>> >     max and
>> >     min voltages testing on my engine.
>> >
>> >     Non Flying RV7 Ian.
>> >
>> >
>> >     OK here is what it looks like down there.
>> >     I'll need a needle scope prob to poke through the insulation.
>> >     I'll give it a try after lunch.
>> >
>> >      From the RX8 schematic it looks like a FET merely grounds
>> >     the coil when it wants a spark. AKA low side switching.
>> >     To check the avg current will require a major disassemble
>> >     and a jumper so I ain't doing it :)
>> >
>> >     Jim M, here are the schematics in case you don't already
>> >     have them. Good start on figuring out the RX8 PCM schematic.
>> >
>> >     Ian If I were you I would set it up on the bench and use
>> >     an FET to fire it at 3000 PPM (6000 RPM) and measure the
>> >     temp rise. Cars don't run 6000 RPM hour in and hour out.
>> >
>> >     --
>> >     Paul Lamar ...No rotor no motor.
>> >
>> >
>> > Hi Paul,
>> >
>> >     FYI, the RX8 coils fail frequently in racing (1 or more a race) but
>> > I am not aware of any failing in street use - although they may and I
>> > haven't heard of it.
>> >
>> > Jim Mederer
>> >
>> > Thanks Jim. I think we are seeing that too. We have a few years
>> > with Chevy V8 LS1 coils and they seem to be fine.
>> > Actully Denso made in China :)
>> >
>> > Paul Lamar ...No rotor no motor.
>>
>>
>> Paul,
>>
>> Thanks for your efforts, I will get the scope onto mine. The 11 volts is >> a
>> bit of a puzzle. I would have expected 14 volts. Maybe there is a ballast
>> resistor. Do you have the circuit diagram?  How is ppm calculated from >> rpm?
>> After reading Jim Mederer's email I am inclined to purchase a set of LSI
>> coils.
>>
>> Ian Beadle
>>
>>
>> You are looking at the bottom of the coil so there
>> are drops.
>>
>> Come to think of it I was wrong. Each rotor fires once per rev
>> so it is not 3000 ppm but 6000 pules per minute.
>>
>> No circuit diagrams of the coils. Always a mystery
>> what exactly is in there.
>>
>> Tracy has been flying LS1 coils for quite awhile.
>> So have some other people. No reported troubles so
>> far.
>>
>> Paul Lamar ...No rotor no motor.
>>
>
> Tracy has had at least three failures of the D580 coils (truck version)
> but none with the D581 (Corvette version).  There is also a D585 that
> has the same connector as the D580 and also has a heat sink on it.  I
> don't know of any use history on it and it's more expensive.  I bought
> a set of coils on ebay that are supposed to be higher output, but
> haven't tried them.  They are at the hanger and I don't remember the
> number.  Also, I think the 2006 Corvette coils were changed and now have
> the smaller connector.  That may be the version I got on ebay.
>
> Bob W.
>

Bob,
My notes say that Tracy had the failures with the D581 and then went back to
D580's - this is all terribly confusing, still the heat sink is a good idea.
George ( down under)



You are right George.  The D581 is the truck version with the small
connector and the one Tracy has had trouble with.  The D580 is the
Corvette version with the larger connector.  The D585 is a replacement
for the D581 with the small connector.  (I'm holding one in my hand so
I'm sure.)  The 2006 and apparently the 2005 Corvette version is a D514A
and I'm not sure which connector it uses. I think it's the smaller
one.  I have both styles of 4 pin low voltage connectors although only
the larger one is shown in the catalog (I am trying to get an airplane
finished.) See catalog by going to the http address in last line of my
signature. Magnecore supplies the high voltage lead to the spark plug.
I hope this is all correct now.  I can find out for sure which
connector the D514A uses tomorrow.

Bob W.

-- 
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