Switched 12 volt source?
Cargo Master
Joined: Mar 2008
Posts: 2,562
Likes: 206
From: Washington
What is the primary resistance of the coil?
I also would recommend increasing the wire size a little. Ford was never very generous with the copper wire that they used.
Jim
Logistics Pro
Joined: May 2015
Posts: 4,463
Likes: 954
From: Tri Cities, TN
You need to run two separate wires if you are determined to use the ignition circuit. I don't know how many amps Edelbrock's electric choke pulls but some of them can pull up to 20 amps when heating up.
Cargo Master
Joined: Mar 2008
Posts: 2,562
Likes: 206
From: Washington
How much extra (amps) can you pull through a stock ignition switch before it fails.
Same reason I asked about the coil you were going to use. They don't all draw the same amount of current (amps) .
Jim
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Cross-Country
Joined: Jul 2025
Posts: 67
Likes: 34
From: Butler County, IA
I'm looking at the Ignitor II system and 45011 Flame Thrower II coil to match. I've reached out to their tech dept, for the running amperage draw and am awaiting their reply. Using a relay may be a good safety option (they list one in their installation guide). I'm unsure on the amp draw of the choke...
Cargo Master
Joined: Mar 2008
Posts: 2,562
Likes: 206
From: Washington
I'm looking at the Ignitor II system and 45011 Flame Thrower II coil to match. I've reached out to their tech dept, for the running amperage draw and am awaiting their reply. Using a relay may be a good safety option (they list one in their installation guide). I'm unsure on the amp draw of the choke...
It is possible the the "computer chip" in the Pertronix II might have the ability to limit current flow.
I believe the original Pertronix module was just an ON/OFF switch, similar to points opening and closing. If you leave the key ON and the magnet stops at the correct spot, you would have constant current flow. (engine not running)
Please post what the tech dept says.
Jim
Last edited by JimsRebel; Jan 2, 2026 at 02:59 PM.
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Cross-Country
Joined: Jul 2025
Posts: 67
Likes: 34
From: Butler County, IA
I haven't heard back from Pertronix on the amp draw question, but I'm going to solve both of these issues by using their #2001 relay kit to power the ignition and choke. It allows me to keep the resistor wire to trigger the relay. It comes with a 30a relay so that should be plenty of power for both the ignition and electric choke. The only semi-complicated part of the installation will be the soldering in of the supplied diode, to stop the feedback from the voltage regulator. I'll post back once all the parts are here and it's done, which will be awhile since there are other "issues" ahead on the to-do list...
Last edited by gstrom99; Jan 2, 2026 at 05:40 PM.
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Cross-Country
Joined: Jul 2025
Posts: 67
Likes: 34
From: Butler County, IA
If you double the supply voltage to the coil and half the primary resistance of the coil primary... The math works out to a 4 times current increase.
It is possible the the "computer chip" in the Pertronix II might have the ability to limit current flow.
I believe the original Pertronix module was just an ON/OFF switch, similar to points opening and closing. If you leave the key ON and the magnet stops at the correct spot, you would have constant current flow. (engine not running)
Please post what the tech dept says.
Jim
It is possible the the "computer chip" in the Pertronix II might have the ability to limit current flow.
I believe the original Pertronix module was just an ON/OFF switch, similar to points opening and closing. If you leave the key ON and the magnet stops at the correct spot, you would have constant current flow. (engine not running)
Please post what the tech dept says.
Jim
Hello,
Thank you for your inquiry. The amperage draw for the installation you described is approximately 1 amp for the module and up to 15 amps for the coil.
Please let us know if you have any further questions.
Best regards,
Travis
Travis H
PerTronix
(913) 808-AERO (2376)
www.PerTronixBrands.com
Cargo Master
Joined: Mar 2008
Posts: 2,562
Likes: 206
From: Washington
Thanks for posting the information from the techs.
I really don't know what the choke will draw. The amp flow will decrease as it heats up.
The risk is that the initial surge current of the choke, plus the ingition current, could be more than 30 amps.
I usually design stuff to have a 50% safety margin.
So I would use 2 relays, one for the choke and one for the ignition.
Good luck, Jim
I really don't know what the choke will draw. The amp flow will decrease as it heats up.
The risk is that the initial surge current of the choke, plus the ingition current, could be more than 30 amps.
I usually design stuff to have a 50% safety margin.
So I would use 2 relays, one for the choke and one for the ignition.
Good luck, Jim
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Cross-Country
Joined: Jul 2025
Posts: 67
Likes: 34
From: Butler County, IA
Thanks for posting the information from the techs.
I really don't know what the choke will draw. The amp flow will decrease as it heats up.
The risk is that the initial surge current of the choke, plus the ignition current, could be more than 30 amps.
I usually design stuff to have a 50% safety margin.
So I would use 2 relays, one for the choke and one for the ignition.
Good luck, Jim
I really don't know what the choke will draw. The amp flow will decrease as it heats up.
The risk is that the initial surge current of the choke, plus the ignition current, could be more than 30 amps.
I usually design stuff to have a 50% safety margin.
So I would use 2 relays, one for the choke and one for the ignition.
Good luck, Jim
Last edited by gstrom99; Jan 7, 2026 at 05:07 PM.
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