Hi all,

just putting the finishing touches to my megajolt install, and I can't fathom for the life of me why there is a capacitor that seems to be used in grouding the 12v +ve feed.

Any ideas? is it needed?

Many thanks

Its not needed its part of the radio suppression in the original fitment.
Paul.

excellant

Many thanks Paul.

The capacitor would also smooth out any transient 'spikes' in the power supply line.

I'd put it in, even if there was one in the circuitry internally; which there should be anyway.

Cheers,
Syd.

Found this on the net when I was wiring my ignition

Cheers

Fred W B

Adding a Capacitor:
Here's the part you may have heard of, but never paid much attention to. Adding a capacitor when installing an MSD offers several advantages and is very benificial to a long lasting ignition. MSD calls it a "Noise Filter," but it is simply just a cap. Typically, these are used to help filter out any radiated noise from the ignition to your electrical system which can cause some radiated noise through your stereo. For most of us this won't be a problem. The important thing is that this cap also filters the power going to the MSD. This will prevent power surges and spikes from damaging the MSD. Things like jump-starting your car are very tough on sensitive parts, but using a cap will provide the protection you need.

At this point, you have the option of either ordering the MSD part (PN 8830), which is what I recommend, or going to your local electronics part store and picking one up. If you do the latter, you will need one of at least 25,000 microferrad and 16 volts. Anything bigger will be fine, but any larger than 50,000 microferrads will simply be overkill. Just make sure that it's at least 16 volts and not just a 12 volt cap.

To install the cap, simply run the power lead for the MSD to the positive terminal of the cap. Then run a wire from this same terminal on the cap over to the battery. At this point you have two options: You can either run the negitive lead from the MSD much the same way - to the cap and then to ground, or you can simply ground the MSD and then ground the cap - independently. (Both methods are shown below) Either way will work just as well, just go with whatever install method you think will fit your install best.




Understand that adding the cap may be the one thing that makes the differance between an ignition that lasts the life of the car -vs- one that only lasts to the end of the year. After having installed around a hundred of these Ignitions, I can assure you it really does make all the difference. The only two I've ever seen go bad, didn't have a cap installed.

The one fitted to Fords with edis is about 2 microfard ,it is a square plastic cased one and is usually located near the coil mounting bracket and connected to the +12v line to the coilpack.I have ran my car for 2 years without one and most other people dont fit one either.The Megajolt has its own transient and surge protection in the power supply circuit.
It will however do no harm to fit it, but is unlikely to be beneficial.
25000 microfarads is overkill for this type of system but may be required for MSD if it has a high current drain, a small capacitor is sufficent to filter out high frequency noise and spikes as the battery also smoothes the voltage .
Paul.

quote:

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MSD if it has a high current drain,

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