Ballast resister need?

[RECHRGD]

I just read an article about ballast resistors in the new Mopar Muscle.  They stated that, if you have an electronic ignition, you don't need to use it.  You may even get better performance, but maybe lessen the life of the coil.  I have a Mallory Unilite unit that was on the car when I got it 13 years ago.  I can't find the old paperwork now, but I thought that it recommended using the resistor.  The resistor has been in place all these years with no ill effects.  Just wondering if there is really any performance gain to be had without it.  I always carry a spare coil anyway.  Any thoughts on this?  Thanks,  Bob

[Troy]

I'm no expert but I've been fighting and researching ignition problems for a couple of months now.

It's a confusing subject. The ballast resistor lessens the power *to the coil* when the key is in "run" (it is bypassed during "start"). The electronic ignition unit always gets full voltage (it needs 12 volts). If you use a good coil - one that can dissipate the heat from constant high voltage - you can generally skip the ballast. However, some coils will recommend a lower resistance ballast to keep them from cooking. For example MSD has a .80 ohms version where the stock one is about 1.5 ohms. This gives more voltage but not full voltage. For a race car the ignition is only on for a few minutes but it may need to be on for several hours on a street car.

If you use certain after market ignitions (MSD for instance), the coil is powered through the ignition module and doesn't get constant voltage. It's only powered when/as needed so there's no need for a ballast at all.

Troy

[RECHRGD]

Maybe I should take my wife's advice......."If it ain't broke, don't fix it".

[Troy]

I think as long as your spark is white/blue you don't need to worry about it. It's good to remember that you can survive without the ballast if necessary (say when yours goes bad in the middle of nowhere and you don't have a spare).

Troy

[John_Kunkel]

The electronic ignition unit always gets full voltage (it needs 12 volts). If you use a good coil - one that can dissipate the heat from constant high voltage - you can generally skip the ballast.

But the (-) side of the coil gets increased voltage without the ballast and the ECU might not be able to handle that.

[Troy]

The electronic ignition unit always gets full voltage (it needs 12 volts). If you use a good coil - one that can dissipate the heat from constant high voltage - you can generally skip the ballast.

But the (-) side of the coil gets increased voltage without the ballast and the ECU might not be able to handle that.

So then we're back to *which* electronic ignition box is used? Has any manufacturer published specifications (ie max input/output on each wire)? Everything I'm finding falls under the category of "I've been running it this way for years with no problems". Not exactly scientific.

Here's something I found specific to this thread:
http://www.moparchat.com/forums/archive/index.php?t-68443.html

Reading elsewhere I found that the Mopar Electronic Ignition ballast should be 1.2 ohms (~10 volts to coil?). My stock/original type ballasts show 1.5-1.7 ohms on my multimeter (~8 volts to coil?).

Troy

[John_Kunkel]

My comment was in reply to your statement "The electronic ignition unit always gets full voltage (it needs 12 volts)." This is true of the Mopar ECU's but not most aftermarket units where the keyed power is only used to turn the unit on...they will work on more/less voltage.

The Mopar ECU also has one pin that gets unreduced battery voltage but my comment referred to the pin that gets reduced voltage through the ballast..if the ballast is eliminated on that setup the higher voltage might damage the ECU.     The instructions that come with the Mopar electronic conversion kits says the ballast is .5 ohms.

I find that measuring such low resistance values is usually inaccurate due to the resistance in the meter cables...touching the probes together might show .2-.4 ohms which must be deducted from the measured resistance.

[Troy]

I see. I have read a lot of topics about electronic ignitions not working right and many times it ends up being a faulty ground or too little voltage to the ECU. I suppose it still makes a difference which combination of parts you use.

I suppose my tester is off because I have three Mopar Electronic Ignition kits and none of the resistors show .5 ohms. The instructions I got don't list a value for the resistor.

Troy