This is the only other ignition in the world that is specifically
designed for a two rotor.
It is lower cost by about $150 compared to two Mallorys
Probably $900 lower cost than the M&W.
I could also include two LM1815 circuits that would condition the
pulses out of the stock crank angle sensors for a few dollars more.
If any one wants to build one I can do a circuit board for them.
-------------------------------------------------------------------------------------------
If any body has a 2nd RX7 ignition system the waste spark coil
will work with this CD system. You will need two for a 2 rotor.
This will save you a lot of money. You can buy them cheap on ebay I
am sure.
I found the old LM1815 are no longer available in dips so they must
be surface mounted. Not that hard for this part. It can easily be
done with a small tip on a soldering iron.
---------------------------------------------------- Ops I found some
LM1815 dips on ebay at a great price. Just over a buck apiece.
Steve, get some of these and send some to me. About ten would be
about right.
Here is the schematic with the LM1815 on board. These are wonderful
chips for taking in CAS signals an outputting a simple pulse.
Megasquirt uses them as well. Why they are not making the dip
versions anymore is a mystery to me. Dips are much easier to
experiment with.
Here is the schematic with the LM1815's.
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The other relatively expensive part is the 1 mf high voltage capacitor
that stores the charge. It is 760 volts. I could not find one with
less voltage.
Here it is one Digi Key for $2.83 cents each.
Still working on the transformer.
Paul Lamar
I would be keen for a couple of boards, If you are not making a few
complete units. I already have the coils lying around somewhere.
Richie Barrow
I am not ready to do the PC boards quite yet. Steve Carlisle will
take it over when I get a bit further along.
I usually order 3 PC boards at a time as they are cheaper that way.
------------------------------------------------------
Here is the Express PCB layout for two LM1815 CAS conditioners. 16
pin dip versions.
It is to scale. The resisters are quarter watt as I recall but 1/10
watt would work.
Attached is the pdf on the transformer I will try. I got a free
sample. They about $6 each. If they work they are a real bargain.
This is one of the hardest parts to make.
Paul Lamar
Just about any waste spark coil will work if it does not have a
transistor switch inside or igniter. In general they would have
three connections but not always. Ground, 12 volts and a trigger
connection.
In fact I am not sure if the second gen RX7 Denso will work as I
found a label on on it that said "w/igniter". It only has two
connections. And the primary is about 1 to 2 ohms.
The primary winding on these non transistor coils is about 1 ohm. So
that will draw about 12 amps.
Use an ohmmeter to measure the primary resistance. If it is one or
two OHM it probably is a non transistor coil. The RX7 second gen
waste spark coil was about 1.5 ohms so I assumed the 2nd gen igniter
fired it.
If you connect a heavy duty push button switch from the negative
side of the coil to ground and a 12 volt battery connected to the
plus side it will fire a simple, old non transistor coil with a
spark plug connected when you tap the switch.
Any coil used with a distributer with points is a non transistor
coil.
Paul Lamar
I will be interested in these boards, as I have been unsuccessful in
obtaining local assistance with Tracy’s ECU and don’t want to be in a
totally unsupported environment in the future. All of my local IT guys
say the environment is too old and it would be a very long project to
get it all updated and running.
Hopefully the outcome of all of this great work will result in a CDI and
EFI environment that those of us with less expertise in this area can
install and operate. The CDI units in the $150 range seem reasonable,
but the $1500 solutions are out of reach. Paul I scanned my old emails
and did not find the one where you listed example Maximize code for the
EFI. Can you please re-post?
BTW, I have completed the header/muffler for my installation. A few
pix are attached, including one showing the internals. The internal
holes are equivalent in area to the 3” tailpipe.
It ended up being a little heavier than anticipated (13 lb, 5 of which
is the Racing Beat header flange), as well as a little bigger. This is
close to the weight of the stock header alone. Width: my cowl will need
to handle 14” from center on this side, although I could have part of
the cylinder outside of a more narrow cowling, which might cool better.
14” is about as wide as a horizontal piston engine. I can shed possibly
another pound or so and narrow the slip joints 3/4” if needed. Note
that the 1/ 1/2” tube running through the cylinder is for cooling air
flow and does not connect with the exhaust. I looked at installing it
on my RX-8 as a test, but that it is not practical. If anyone has a
running renesis engine and would like to borrow it for testing, please
let me know.
Scott Gettings
Once you take the ignition problem out of the computer the EFI part becomes
much simpler. A very simple system will keep the engine running while you
can tune it with a manual mixture control. A simple bench set up consisting
of mass air flow sensor, a Maximite and a transistor controlling a fuel
injector
goes a long way towards developing a simple system that will work.
In fact you don't need a real mass airflow sensor as a small pot
connected to five
volts can simulate a mass air flow sensor variable voltage.
Boils down to reading the mass air flow sensor and adjusting the pulse width
on the injector depending on how much air is going into the engine.
It can do this ten times a second or faster.
It is easier than a car EFI system as you have a well defined prop load
that is a simple
function of RPM. No rapid acceleration is needed.
Paul Lamar
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