Re: To coil or not to coil
[Re: Gabmando]
#2779794
05/30/20 03:54 PM
05/30/20 03:54 PM
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Joined: Aug 2003
Posts: 42,992 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 42,992
Bend,OR USA
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Ballast resistors where used to reduce the voltage from 12V to 8 volts to help stop the points from pitting when the car makers switch to 12V from 6 volts back a long time ago, 1953 to 1956. Todays ECU act as the switch to the coil like the points use to do I think you can use either one on your deal with the standard single ballast resistor for your ECU
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: To coil or not to coil
[Re: Cab_Burge]
#2779814
05/30/20 05:05 PM
05/30/20 05:05 PM
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Joined: Jan 2003
Posts: 3,122 Auburn WA
Dave_J
master
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master
Joined: Jan 2003
Posts: 3,122
Auburn WA
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What you want at the final (Coil and Ballast) is about 2.7 Ohm's +/- 0.25 Ohm.
The more volts will give a hotter spark. But the ECU has a transistor that provides a timed shunt to ground. If the voltage to the coil is too much that transistor will over heat. If the voltage to the coil is too low the spark is weak.
I have run a 1 Ohm Ballast with a 1.5 Ohm coil on an Orange Box ECU for years. My son tried a 0.5 Ohm Ballast with a 1.5 Coil and burnt out a few ECU's before we finally put a 1.2 Ohm Ballast on, no more failures. A Pertronic's Flamethrower 0.3 Ohm coil and no ballast gave one very hot spark but the ECU lasted 1 week.
If this is a street/strip driver, ether of those coils are good.
But in a race car, a 1.5 Ohm coil is a 1.5 Ohm coil is NOT true. There are many things to take into account. Turns ratio is a big one. More turns will give a bit hotter spark, IE, A MSD Blaster is 120 turns and an OEM is about 90-100 turns. But a lot of newer 'E' coils will be even hotter.
Picture stolen from B Bodies Only
Retired, US ARMY 1973-1994 ASE mechanic, Electrical 1994-1997 Retired GTE/VERIZON/FRONTIER 1997-2015
Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.
03 Suzuki Burgman 650(Burger King) Scooter 65 Formula S Cuda 78 Little Red Express Truck 98 Buick Regal (wifes car)
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Re: To coil or not to coil
[Re: Gabmando]
#2782856
06/08/20 03:29 PM
06/08/20 03:29 PM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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Thank you Dave. Bottom line is, the ballast resistor is needed to "protect" the coil and the ECU even if a 4 pin ECU is used instead of 5 pin. This is bone stock 1973 Charger Rallye 340CID 4 SPD. The factory system is just fine. Not when using the Accel super coil. The resistance of the primary winding in the super coil must be ok to work without a ballast using the MP orange ECU. I have been running that setup for 5 or more years and never a problem. I actually don't remember the ohm reading on the super coil but I have one out in my garage I will check later. And that coil never got hot either as I checked it a lot. The factory system may have to have it as you stated though. Ron
Last edited by 383man; 06/08/20 03:30 PM.
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