Ballast resistor

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prorac1

prorac1

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We are using a mopar electronic distributor and an MSD blaster 2 coil.

Is a ballast resistor required for this combo?

And under what circumstances can you remove the ballast resistor?

Thanks. Eric
 
Protrac,
It is my opinion that the distributor just furnishes the pulse to the control box, MSD in this case. The MSD unit switches the coil current on/off to generate the spark. The use of a ballast resistor will be determined by the control box (MSD) and the coil being used. The ballast resistor LIMITS the current in the circuit to required amount that the MSD unit can safely switch and the coil can tolerate. If you arbitrarily eliminate the resistor, you run the chance of damaging the MSD box and coil. Read the instructions that came with the MSD box and coil or call MSD and ask them how to proceed. They are the best source for information NOT your next door neighbor's brother-in-law's cousin's friend's best buddy, who, likely has no clue to your question but has all the answers.
Bob Renton
 
prorac1 said:
We are using a mopar electronic distributor and an MSD blaster 2 coil.

Is a ballast resistor required for this combo?

And under what circumstances can you remove the ballast resistor?

Thanks. Eric
Click to expand...
Probably yes. It depends on the Electronic Control Unit you are using with that distributor. A Chrysler ECU will require a ballast resistor.
 
Look up the gm style HEI setup and replace the chrysler box with it. Cheap upgrade and you will think its a different engine.

That is unless you going for correctness.
 
RJRENTON said:
Read the instructions that came with the MSD box and coil or call MSD and ask them how to proceed. They are the best source for information NOT your next door neighbor's brother-in-law's cousin's friend's best buddy, who, likely has no clue to your question but has all the answers.
Click to expand...

Thiat is the best advice anyone has ever given.


Instructions for a Blaster 8200 or 8203 coil (not sure if it is yours):
http://www.jegs.com/InstallationInstructions/100/121/121-8200.pdf
 
RJRENTON said:
Protrac,
It is my opinion that the distributor just furnishes the pulse to the control box, MSD in this case. The MSD unit switches the coil current on/off to generate the spark. The use of a ballast resistor will be determined by the control box (MSD) and the coil being used. The ballast resistor LIMITS the current in the circuit to required amount that the MSD unit can safely switch and the coil can tolerate. If you arbitrarily eliminate the resistor, you run the chance of damaging the MSD box and coil. Read the instructions that came with the MSD box and coil or call MSD and ask them how to proceed. They are the best source for information NOT your next door neighbor's brother-in-law's cousin's friend's best buddy, who, likely has no clue to your question but has all the answers.
Bob Renton
Click to expand...

We are using the MSD coil with the mopar ECU. So it means the ballast stays. Thanks. Eric
 
fklskv said:
Look up the gm style HEI setup and replace the chrysler box with it. Cheap upgrade and you will think its a different engine.

That is unless you going for correctness.
Click to expand...

We have also considered going this route to simplify wiring. That distributor along with the blaster coil would make for a pretty simple setup.
 
prorac1 said:
We are using a mopar electronic distributor and an MSD blaster 2 coil.

Is a ballast resistor required for this combo?

And under what circumstances can you remove the ballast resistor?

Thanks. Eric
Click to expand...

Here is a document that I found once about that.

This is true with a CD ignition like MSD, Mallory And Crane sell or with any ECU that is internally regulated(like GM HEI or Pertronics). According to MSD(this is not me making this stuff up) the Mopar boxes are not internally regulated and need to have a total resistance (coil primary + ballast) of at least 1.5 ohms. The Blaster2 coil has .7 ohms of primary resistance and comes with a .8 ohm resister for a total of 1.5 ohms. MP's literature on ballast resistors is confusing at best and many catalogs and advertisements incorrectly state that an Orange box and Blaster2 coil can use a .25 resistor. Maybe this is one reason the Orange box has such a bad reputation.

The .25 resister is for racing with a chrome box and a 100 wind coil equivalent to the blaster2. Use under 3000rpm should be limited to less than 30 minutes to avoid overheating the ecu. With no resister it would overheat even faster. Just like the orange box, for street use a .8ohm or more resister is necessary.
 
Yes, ballast. I "went HEI." As an experiment at the time, I DID NOT USE a separate heat sink. I simply screwed the HEI to a flat spot on the firewall, someone had already made one hole, so I made another. Ran the car through parts of 2 summers that way with 90-100F heat
 
bbeep71 said:
Here is a document that I found once about that.

This is true with a CD ignition like MSD, Mallory And Crane sell or with any ECU that is internally regulated(like GM HEI or Pertronics). According to MSD(this is not me making this stuff up) the Mopar boxes are not internally regulated and need to have a total resistance (coil primary + ballast) of at least 1.5 ohms. The Blaster2 coil has .7 ohms of primary resistance and comes with a .8 ohm resister for a total of 1.5 ohms. MP's literature on ballast resistors is confusing at best and many catalogs and advertisements incorrectly state that an Orange box and Blaster2 coil can use a .25 resistor. Maybe this is one reason the Orange box has such a bad reputation.

The .25 resister is for racing with a chrome box and a 100 wind coil equivalent to the blaster2. Use under 3000rpm should be limited to less than 30 minutes to avoid overheating the ecu. With no resister it would overheat even faster. Just like the orange box, for street use a .8ohm or more resister is necessary.
Click to expand...
Basically this is correct. There is a table in the Ignition chapter of the Engine book that has recommended resistors for various Mopar Performance ECU and coil combinations. It is a little confusing due to the poor copy editing of most editions. The chrome boxes are particularly confusing because there have been several different ones with different part numbers. Some were OK street, the others were intended as drag strip only.
 
Coffee&Cars said:
<------ MSD 6AL, Mopar electronic dist. Pertronix 60,000 volt coil. No balast Resistor. No problems. This thing craps lightening.
Click to expand...

NO CD/ discharge type ignition uses a ballast. The coil does not have DC (battery) current through it. The coil is used as a transformer, fed a great big pulse of energy from the CD unit. NEVER hook ANYTHING to the coil of an MSD/ CDI except the two coil wires coming from the CD box
 
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