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Old 11-04-2019, 05:16 PM   #7
40 Deluxe
Senior Member
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 3,133
Default Re: Radio Shack Capacitive Discharge Ignition

Originally Posted by all american boy View Post
Thanks Deluxe40

Here is the Wikipedia article about CDI and it's advantages.

It does provide quicker starting in cold weather.Probably with a car that has been sitting awhile too.

Have no idea what you are saying in your post or what facts it is based on.

Might be you are saying you don't like CDI and do not intend to get one.

Even that is a little unclear in your post.
What I was getting at is the fact that a lot of people seem to think that if they buy a 50,000 volt coil, it always fires with 50,000 volts to the plug. That is not true. When the points open (or the CDI or other electronic ignition triggers), secondary voltage in the coil secondary windings rises only to whatever voltage is needed to jump the gap, and then the plug fires. If you watch the pattern on a scope you can see the firing voltage displayed. At idle, firing voltage is typically around 5,000 volts, and rises under load. How high it goes is dependent on plug gap and cylinder pressure. But I have never seen it anywhere 40,000 or 50,000 volts unless you pull a plug wire off or the wire is broken. I run an Accel 300+ CDI type ignition on my 289 '67 Cougar that I drag race and I like it. Runs right to the rev limiter at 76-7800 RPM.
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