EEVblog Electronics Community Forum
EEVblog => Other Blogs => Topic started by: AllTheGearNoIdea on June 03, 2018, 11:03:48 am
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Just been testing a MSD6 electronic ignition system. Wow this thing is shocking powerful compared to a conventional mechanical switching setup. Been busy with a quite a few mechanical projects recently. Best regards Chris
https://youtu.be/mWfgf2uDWoo
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Next time you need to get thick wires through a tight grommet try to use some kind of lubricant, like vaseline or silicone grease.
Works a treat.
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The grommet is split in two and made from rigid plastic and the wires have to go through first. Lubrication would not have helped for this. It could be that there is a special tool that compresses the two halfs of the gland together allowing it to be inserted. Larger plier may have helped.
Thanks Chris
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AllTheGearNoIdea, your bench psu is grossly overloaded. That MSD box pulls 36 amps peak through the thick battery feed wires. Put 50,000uF across the supply line. When you are single pulsing triggering it at the start it should give a ~1kHz chirp, not the lame noise it actually made.
Rant mode on/
I have been making ignitions since 1977 and fiddling with (mostly repairing) MSD ignition boxes since 1981. IMHO they are a great steaming pile of doggie-doo. The advertising dept of MSD are provably and measurably flat out liars. They claim for that box 100mJ spark energy. Certainly the box puts out 100mJ but a great deal of that energy is channeled through a clamp diode back in to battery positive. That, combined with coil losses means that with a good E-core coil you only get typically 35mJ out of the secondary, and if you use an old fashioned points coil you only get 25mJ out of the secondary. The duty cycle of the secondary current when multi-sparking is advertised at ~40% according to the brochure, but in truth is it about 12.5%.
Rant mode off/
My discussion on an ECU hacking forum -> https://pcmhacking.net/forums/viewtopic.php?f=22&t=3364 (https://pcmhacking.net/forums/viewtopic.php?f=22&t=3364)
and with some (but not all...) *very* smart engine-smart guys -> http://speedtalk.com/forum/viewtopic.php?f=1&t=42274 (http://speedtalk.com/forum/viewtopic.php?f=1&t=42274)
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Schematic of box http://web.tiscalinet.it/giordy/ECU/msd6a_02.pdf (http://web.tiscalinet.it/giordy/ECU/msd6a_02.pdf)
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Watched the video, went to your channel and saw the bike project you are helping out on. Looking forward to seeing updates on this.
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Circlotron
No my power supply is not grossly overloaded it can easily deliver 20amps all day long. The unit doesn’t draw anyway near your quoted current even when running off a full charged lead acid battery. I don’t think the suggested capacitor would have help as I have more than a farad in circuit already, I use this bench for testing high power transmitters. It possible it could draw more at high RPM but this was outside my useage case so didn’t do that testing.
I note that your scope measurement look very similar to my own measurement although not sure what order of magnitude. I did not show all my measurement and lost some footage in the video.
I did check the supply using the scope and it’s not dipping less than a few mv and the connecting cables to the PSU are 4mm sqr. There may be some high peak current but they are short.
I cannot refute the MSD marketing info myself I can say that the MSD does perform significantly better thatn other electronic ignition systems that I have repaired in the past. I don’t know if other manufacturers use the capacitor discharge method but it certainly works. The vehicle it’s fitted to does run and drive significantly better using the MSD6 and I would be happy to recommend it.
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For those that want a update
https://youtu.be/dI6dzvD7HGY