single cylinder motorcycle megajolt build

Johnny · Post by **Johnny** » Sat Feb 14, 2009 12:20 am

Going to be picking up a megajolt after timing wheel comes in ,, hopefully before March.

Have heard of someone using a megajolt on a single cylinder motorcycle with great results.
I believe the coil used was a COP (Coil On Plug) I think that a two wire style was needed.

Ben looking into high output COP from Accell, Malory etc.

Anny recomandation of a COP requirement to work with the EDIS modual?

Thanks
John

Johnny · Post by **Johnny** » Sun Feb 15, 2009 12:13 am

Did a little searching in this forum and on the net and what everyone seems to agree on when matching a coil to a module,
is to get the primary resistance as close as possible. Thain everyone seems to have a difference of opinion.
The Ford coil pack (primary .5) (secondary 11-13k ohms)

Did a little digging around and found a few Accel coils with the primary resistance of
.5 to .7 ohms
Secondary resistance came in at 9.5k to 10.8k ohms

COP secondary resistance seems to be in the 5.43k ohm range 50% less,,,,, Does that even matter???

http://store.summitracing.com/partdetai ... toview=sku

I am thinking about using one of these
http://www.poweredbyford.com/store/inde ... ts_id=3256
http://www.poweredbyford.com/store/inde ... ts_id=3257

I believe with a EDIS 4 I would need to wire the coil to ether (A coil: pin #10) or (B coil: pin #12), and run power to the coil.

Also from what I understand if I pickup the EDIS 4 modual, and a coil, It should run without the Megajolt
and be in limp home mode witch should be a 10 deg. advance.

DannyP · Post by **DannyP** » Sun Feb 15, 2009 1:11 pm

Johnny, you are right about the limp home mode. I believe all that matters is the primary resistance of the coil. And power to the coil and picking one of the coil outputs should work for you.

Good luck.

Johnny · Post by **Johnny** » Sat Mar 21, 2009 11:57 am

And the saga continues!!
Been playing around with an ignition coil circuit simulator
http://www.bgsoflex.com/igncoil.html

and plugging in values from a coil
http://store.summitracing.com/partdetai ... toview=sku
Hooking the coil up to one EDIS coil output, I believe might set the dwell at 360 degrees, and
puts the primary amps over 15amps and up to 20 amps, and secondary voltage over 140,000 volts??????
but a coil on plug, witch is designed to be fired less often is pulling over 20 amps as well, but the voltage is lower at 90,000 witch is still crazy high.
http://store.summitracing.com/partdetai ... toview=sku

Is the ignition coil circuit simulator misleading?

Thanks
John

MartinM · Post by **MartinM** » Sun Mar 22, 2009 9:53 am

I haven't checked the calculator at all values, but I've no reason to doubt it...

If you specify a long dwell then you are effectively increasing the charging time to such a point that the current is limited only by the primary resistance of the coil - so the current will be 20v/0.6 ohms = 20 Amps exactly - and cutting the primary current will result in a secondary voltage of some 150,000 volts

Johnny wrote:...Hooking the coil up to one EDIS coil output, I believe might set the dwell at 360 degrees, ..

What makes you think that? Coils aren't designed for 360 dwell angles, so I think you might be on a red herring chase with that belief and the calculator...
(also I can't get my head round when the spark would occur if the dwell angle was 360 degrees)

AFAIK EDIS will work fine with just about any basic wasted spark coil pack (i/e/ no fancy electronics inside - just a regular coil) and definitely works well with the one you've quoted - don't get too tied up with the theory

Johnny · Post by **Johnny** » Tue Mar 24, 2009 12:58 pm

I was thinking that the dwell was from firing of the plug to firing of the plug, but the EDIS probably controls the dwell angle.

I ordered a coil yesterday, hopefully have things sparking soon.

Thanks for the input
John

Johnny · Post by **Johnny** » Tue Mar 24, 2009 9:32 pm

Reading through the coil literature and it states,,,,,
"coils are compatible with most capacitive discharge systems that control the dwell period, or limit the current.
(For 12 volt negative ground systems)

Does the EDIS control the dwell period, or limit the current?

Found a little info on the EDIS

The EDIS module has its “dwell” built and is NOT adjustable, (coil “ON” vs “OFF” time). Ford engineers set that dwell time to match the coils rise time. If the new coils rise time is slower than the EDIS coil pack, when the coils are triggered, the spark intensity delivered will not be at the full potential of what that coil is capable of, and if boosted, could end up not sparking at all. On the other end of the dwell spectrum, if the new coils rise time is faster than the EDIS coil packs, then the new cols will burn out, and how long that happens depends on how much the coil is being “oversaturated” (turned on too long causing the coils to heat up…)

Thanks
John

DannyP · Post by **DannyP** » Wed Mar 25, 2009 9:45 am

I think you will be ok, as long as the primary resistance is in the ballpark.

Don't worry about it, it will work just fine.