Autosport Labs

Hi,

Any ideas or reasons why Megajolt/EDIS woild NOT work on a 2cyl set???

Peter

I don't see why it wouldn't. You'd take an EDIS-4 and two separate coils, connect output for coil 1/3 to one coil and output for coil 2/4 to the other coil. That should give spark, now whether the timing of this spark will be suitable for your engine is something else..

A 4-cylinder wasted spark system should be ideal to run your motor. The RPM readout on the PC will be twice what the car's actually running, but you'll still be able to manipluate the map. Go on, be a pioneer! Just remember to insulate the two unused coil connectiins.

What's the top RPM of your 2 cylinder engine? If it's more than 5000 perhaps firmware have to be modified, not a big deal though.

Modifying the firmware IS a big deal to mere mortals who..
... may not understand how the MJLJ firmware works in general
... may not be familiar with the assembler language used
... may not know which parts of the firmware (eg code only, data tables only, or both) need changing
... may not know exactly what needs changing and whether there are any side effects of making those changes
... may not have access to the appropriate Motorola development kit software ...
... ...and may not have knowledge of setting it up on a PC or using it
... may not have the ability to reprogram the new firmware into the processor
... may not have access to a test bed that isn't a real engine to test it with

If none of these apply, then go ahead and modify the firmware - and let us know how you get on

PS All these most definitely apply to me, maybe except the first

Are you sure the MJLJ would see double the actual engine RPM? I don't see why two missing cylinders would make any difference to the crank sensor, EDIS PIP signal or MJLJ. Maybe I am missing something, but I think it should work with no changes required.

The easiest way approach this:

1. Get the EDIS-4 module working on it's own on your 2-cylinder- run it at the default 10 degrees BTDC. See how well it runs.
2. If it runs well enough, then add the MJLJ control- you'll have to manually compensate for any RPM errors
3. If it's set and forget- then stop: you're done!
4. If you really want accurate RPM readings someone might be kind and make the appropriate changes.


just $0.02 from a mere mortal.

Hi All,
For a start I am pleasantly suprised at the feedback.
Thanks all.

My tuppence worth.

1.The 2CV has a double ended coil wih NO distributer, so I assume it is a wasted spark it is standard form.
2.The big problem is the sensor wheel, as front pully has no (woodruff) keyway to locate trigger wheel to a fixed position.
3.Propose to fit trigger between crank and flywheel but space is very limited, may need to machine a mm from flywheel?
4.Static timing is set at 8deg BTDC,
5.Can the static timing be changed in the MJL parameters.
6.RPM I believe is derived from the trigger wheel so I assume:) is will be correct.
7.Max RPM is 6000rpm? (as no Rev Counter fitted)

The standard 2CV ignition is wasted spark anyway. The engine is half of a 4 cylinder engine, and only needs one coil. Use the EDIS-4 and just connect the 1/4 coil. There should be no changes at all for the firmware, and the RPM values should be correct.

RE #1: Waste spark fires two cylinders at a time, you only have two cylinders, thus it can not be a waste spark. What it could be is two coils in one package. Remember that you need two coils, you'd then connect them each to output for cyl 1/3 and 2/4.

RE #5: Static timing is old distributor days lingo, it refers to timing before it starts being altered via RPM and VACUUM. Once you get digital ignition in, there is no such thing as static timing. Timing will be taken from cells, MJL has 100 cells, 10x10 table, it looks at present RPM and VACUUM and decides which cell to use. If you run EDIS-4 only (without MJL) then your ignition will run at static 10 BTDC and timing will not be altered.


You need to try to make that thing rev past 10,000 rpm!!!!!

Alex - of course it can be wasted spark - it just means it fires on the exhaust stroke.

That's MSD.

OK, I'll take the bait....

It's not MSD (as in Multiple Spark Discharge) at all - that's completely different. Use Google.....

"Examples of engines using this design include the Buick V6 engine Series I and newer, Harley Davidson V-Twin, BMW Airheads, Citroën 2CV, Mazda B engine and Chrysler V10."

http://www.answers.com/topic/wasted-spark

Well, could be anything. The important thing is that one cylinder will be triggered by cyl 1/3 output, and the other will be triggered by cyl 2/4 output. Thus two coils are needed. In fact, this could easily be a true coil over system if two COP units are used instead of coils and wires.