Re: Ballast Resistor Yes or No?
[Re: lewtot184]
#1717566
12/29/14 11:35 PM
12/29/14 11:35 PM
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Joined: Jul 2007
Posts: 11,836 Florida
mopar346
Let me tell ya about fat chicks!
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Let me tell ya about fat chicks!
Joined: Jul 2007
Posts: 11,836
Florida
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A lot of aftermarket pick ups will go bad with 12 volts constant.
Careful, your character's showing!
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Re: Ballast Resistor Yes or No?
[Re: SCATPK]
#1717569
12/30/14 03:12 AM
12/30/14 03:12 AM
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Joined: Jan 2003
Posts: 5,439 So Cal
Sinitro
master
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master
Joined: Jan 2003
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So Cal
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What many don't understand is... The ballast resistor protects the coil from overcurrent...Its resistance increases as it gets hotter.. Traditional coils had thin internal wire windings and could not handle higher currents. Some later coils are designed to handle higher currents, also some do not require a ballast resistor U need to check the maufacturer for their recommendations. Now the traditional oil-filled coil is being replaced with the EL transformer type design, which is more compact.. Just my $0.02...
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Re: Ballast Resistor Yes or No?
[Re: SCATPK]
#1717572
12/30/14 05:09 PM
12/30/14 05:09 PM
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Joined: Jan 2003
Posts: 25,743 Rio Linda, CA
John_Kunkel
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Rio Linda, CA
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The MSD Blaster is a popular coil, the instructions state " Most late model vehicles with electronic ignitions do not require a ballast resistor, check your ignition and manufacturers specifications to determine if a ballast is required in your application."
For points they specify a ballast be used.
OTOH, Pertronix says to use a ballast if the coil isn't within a certain resistance range.
The INTERNET, the MISinformation superhighway
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Re: Ballast Resistor Yes or No?
[Re: John_Kunkel]
#1717573
12/30/14 07:08 PM
12/30/14 07:08 PM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Yes, you should run a ballast with the OEM coil as well as most aftermarket coils. If you don't run it, the life of the coil will be greatly reduced as it will run much hotter and with nothing to limit current going to it. FWIW, I tried to run my MSD Blaster II coil (Mopar chrome box ECU) with no ballast and it was searing hot after 5 minutes. I went to a .25 ohm ballast which dropped the voltage to the coil to 7-8V which kept it much cooler and with no discernable drop in output to the plugs (40-45kV). Use the ballast.
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Re: Ballast Resistor Yes or No?
[Re: mopar346]
#1717575
12/30/14 07:37 PM
12/30/14 07:37 PM
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Joined: Oct 2005
Posts: 4,941 WI
Dcuda69
master
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master
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WI
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Quote:
A lot of aftermarket pick ups will go bad with 12 volts constant.
Not sure which aftermarket pickup coils you mean. The factory style pickup is a pulse generator(I believe MSD is also)it sees NO voltage..it creates an AC signal used as a trigger by the ECU
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Re: Ballast Resistor Yes or No?
[Re: Dcuda69]
#1717578
12/30/14 09:03 PM
12/30/14 09:03 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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Any of you ever burn your finger on the ballast?
Without it there to limit current that heat would be added to the coil.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: Ballast Resistor Yes or No?
[Re: Supercuda]
#1717579
12/31/14 12:33 AM
12/31/14 12:33 AM
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Joined: Oct 2005
Posts: 4,941 WI
Dcuda69
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Quote:
Any of you ever burn your finger on the ballast?
Without it there to limit current that heat would be added to the coil.
Exactly! AND the ECU!!
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Re: Ballast Resistor Yes or No?
[Re: Dcuda69]
#1717580
12/31/14 01:27 AM
12/31/14 01:27 AM
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Joined: Jan 2003
Posts: 1,482 Lake Orion, MI
goldduster318
pro stock
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Lake Orion, MI
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Quote:
Quote:
Quote:
The ballast protects the coil and the ignition module. If you want to bypass you should replace both of these with units that can withstand the current passing through them at 14V.
Its protecting only the coil. If you check the wiring diagram, the ECU gets full battery voltage from the vehicle harness.
As mentioned earlier, the stock distributor pickup doesn't care as it's a Variable reluctance sensor and is not powered. The magnetic field creates AC voltage as the reluctor passes by the pickup.
I ran an Accel 8140 coil for years with a stock replacement ECU and never had an issue.
True the ECU is powered from the harness but it also carries the same current as the coil primary winding because it controls the coil negative on/off. When the coil is "on" current flows through the coil primary to ground provided by the ECU
Here's a pretty good description of system operation copy/pasted from the tech archives..just remember, any current flow through the coil primary also goes through the ECU:
The + wire supplies the power to the coil and the ECU grounds the negative part closing the circuit. This creates a magnetic field in the coil. The coil is what we call an autotransformer. When the ECU receives a signal from the magnetic pickup to fire a spark, the ECU OPENS the circuit, the magnetic field collapses and a spark is generated. A collapsing magnetic field creates a high reverse polarity voltage (energy).
The ballast resistor knocks the voltage down by a few volts to the coil (+) from 12 volts. The ballast resistor is bypassed during starting to produce a hotter spark. Run without the resistor and you will burn the coil up in a matter of minutes.
Simple actually.
Inside the distributor is the pickup and reluctor. The pickup has a magnetic field and a coil of wire. As the edges of the reluctor pass thru the pickup's magnetic field it generates a voltage in the coil, a small voltage and not enough to drive the coil.
This signal is sent to the ECU which uses it to control the coil. The ECU transforms the small pulse from the pick up into a signal of proper duration (this is where the dwell is created) to fire off the coil. It will generate a ground to the coil to allow it to charge up then remove the ground causing the spark.
The coil generates it's high voltage spark by collasping a magnetic field as described above.
The ballast resistor is not there to knock down voltage but to limit current thru the system. It's the excessive current that will burn out a coil. However, being that voltage = resistance times current any drop in current will affect voltage. But it is still the current that does the damage.
Yes, that's true that it carries that current as well, but that isn't an issue at all.
Here's the specs for the switching transistor commonly found on an orange box for reference: http://www.nteinc.com/specs/original/MJ10012.pdf
You won't be causing any ECU issue by deleting the resistor. I've gone 10 years without one with no issues.
'70 Duster 470hp 340/T56 Magnum/8 3/4 3.23 Sure-Grip
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Re: Ballast Resistor Yes or No?
[Re: 383man]
#1717583
01/03/15 02:48 PM
01/03/15 02:48 PM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
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Phila. Pa.
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It depends on the ignition package. A capacitive discharge system (like MSD 505, , 7 etc) or an indutive system that is designed to actively control the current (like the Pertronix mentioned above) will not need the resistor. Everything else was designed to use the resistor(s) for this function. As Christopher Jacobs wrote in his book, for short WOT bursts (1/4 mile) one can try to get a little more out of the coil with a bypass switch. IIRC the purpose is to make up for the lack of time at high rpm for the coil to rebuild its field. Whether it is going to make a difference to performance will depend on what is happening in the combustion chamber. Another variable is how the coil itself is internally designed. They can be designed to perform better at low rpms or at high rpms. It has to do with the windings. If you compare the specs for a Blaster 2 vs a stock coil you'll notice a differnce in windings.
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Re: Ballast Resistor Yes or No?
[Re: Mattax]
#1717584
01/03/15 02:58 PM
01/03/15 02:58 PM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
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Yea the MSD type ign which is the multi-spark up to a certain rpm normally has both coil pos and neg hooked to the MSD control box as it controls the coil primary and can induce like 300 volts into the coil primary and most MSD type ign are designed not to use a ballast as they control the coil primary with their control box. Ron
Last edited by 383man; 01/03/15 02:58 PM.
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Re: Ballast Resistor Yes or No?
[Re: cjskotni]
#1717585
01/03/15 03:02 PM
01/03/15 03:02 PM
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Joined: Feb 2009
Posts: 892 Illinois
StrkrDart69
super stock
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Illinois
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Quote:
Yes, you should run a ballast with the OEM coil as well as most aftermarket coils. If you don't run it, the life of the coil will be greatly reduced as it will run much hotter and with nothing to limit current going to it.
FWIW, I tried to run my MSD Blaster II coil (Mopar chrome box ECU) with no ballast and it was searing hot after 5 minutes. I went to a .25 ohm ballast which dropped the voltage to the coil to 7-8V which kept it much cooler and with no discernable drop in output to the plugs (40-45kV).
Use the ballast.
You have other issues. Ecu should not be getting hot. Also my coil does not run hot.
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Re: Ballast Resistor Yes or No?
[Re: goldduster318]
#1717589
01/03/15 07:12 PM
01/03/15 07:12 PM
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Joined: Jan 2003
Posts: 5,439 So Cal
Sinitro
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So Cal
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Quote:
Its protecting only the coil. If you check the wiring diagram, the ECU gets full battery voltage from the vehicle harness.
Depends upon the year... Certain Mopars used a dual element ballast resistor, this connected to pin 5 of the ECU, protecting it. For early ECU systems, the Mopar engineers were concerned about max voltage to the ECU as to protect its power transistor..
Just my $0.02...
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Re: Ballast Resistor Yes or No?
[Re: Supercuda]
#1717591
01/03/15 09:33 PM
01/03/15 09:33 PM
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Joined: Feb 2009
Posts: 892 Illinois
StrkrDart69
super stock
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Posts: 892
Illinois
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Quote:
Quote:
Go ahead and keep using a ballast resistor.
You wouldn't happen to be an electrician now would you?
No I am a yawner.
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Re: Ballast Resistor Yes or No?
[Re: StrkrDart69]
#1717593
01/05/15 09:47 AM
01/05/15 09:47 AM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
pro stock
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Joined: Jul 2007
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North Carolina
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Quote:
Quote:
Yes, you should run a ballast with the OEM coil as well as most aftermarket coils. If you don't run it, the life of the coil will be greatly reduced as it will run much hotter and with nothing to limit current going to it.
FWIW, I tried to run my MSD Blaster II coil (Mopar chrome box ECU) with no ballast and it was searing hot after 5 minutes. I went to a .25 ohm ballast which dropped the voltage to the coil to 7-8V which kept it much cooler and with no discernable drop in output to the plugs (40-45kV).
Use the ballast.
You have other issues. Ecu should not be getting hot. Also my coil does not run hot.
My coil was running hot, not the ECU.
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