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Author Topic: Tfi coil question,  (Read 1357 times)

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Offline rommel1940

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Tfi coil question,
« on: December 07, 2015, 08:54:43 PM »
I had issues ignition,  so I'm started ordering parts for the tfi upgrade and the biggest question I have is about my coil, I bought a 45, 000 volt coil with 1.4 ohms resistance. I did this because in eaglepdia it doesn't say anything about what I now have been reading about.So from what I understand I will not get the full 12volts needed for full power unless I bypass the resister,  but because I didn't get the 3.0ohm coil, I will burn up my icm.if i do that, so am I cool with the 1.4 coill I already paid for?I don't need full power but a nice upgrade would be nice, advise?
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Online eaglefreek

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Re: Tfi coil question,
« Reply #1 on: December 07, 2015, 10:10:53 PM »
Keep the coil you bought and keep the resistor wire in place. It will work just fine.
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
1981 AMC Eagle Wagon As Seen On TV  Lost In Transmission


 

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Offline rommel1940

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Re: Tfi coil question,
« Reply #2 on: December 08, 2015, 07:24:59 AM »
About how much of the coil voltage do you think I will get , with 1.4 ohm 45, 000 volt?
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Re: Tfi coil question,
« Reply #3 on: December 08, 2015, 09:58:52 AM »
About how much of the coil voltage do you think I will get , with 1.4 ohm 45, 000 volt?
Bill D who doesn't get on here very much anymore would be able to explain it better, but that high output coil stuff is just marketing hype. The coil only delivers what is needed to jump the gap and what I've read, is usually 20k volts max under extreme conditions. The biggest benefit of what I call the big cap upgrade, because there is no TFI (Thick Flim Ignition) module used in the swap, is having the contacts further apart to help prevent cross firing.
« Last Edit: December 08, 2015, 10:04:14 AM by eaglefreek »
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
1981 AMC Eagle Wagon As Seen On TV  Lost In Transmission


 

"I know he'd be a poorer man, if he never saw an eagle fly,
Rocky mountain high"  John Denver
Click for Fayetteville,TN Forecast" border="0" height="100" width="150

Offline carnuck

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Re: Tfi coil question,
« Reply #4 on: December 11, 2015, 10:32:08 PM »
If you run a coil designed to run at 12 volts on only 8, the RPMs drop. You can't rev them like normal.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline rommel1940

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Re: Tfi coil question,
« Reply #5 on: December 12, 2015, 10:43:13 AM »
Yeah I will test this theory with my meter, see how bad it is and go from there
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Offline carnuck

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Re: Tfi coil question,
« Reply #6 on: December 12, 2015, 05:35:29 PM »
Electronics have a tendency to burn up when they are run long term below their operating voltage range. They require a certain amount of voltage AND amperage. If the volts drop, the amp draw goes up. Higher amps = higher temps.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline rommel1940

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Re: Tfi coil question,
« Reply #7 on: December 12, 2015, 07:53:25 PM »
Well from what I read members who do this swap run the full 12v to the new coil, but when they do this the coil hads 3.0 ohms of resistance. From what I understand if I do this with my 1.4 ohm coil I will burn up my icm.but if I stay with my stock wire with resistor I'm ok.i wish I new forsure I would like the full benefits without possibly burning anything up. Reliability is #1
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Re: Tfi coil question,
« Reply #8 on: December 13, 2015, 03:05:39 AM »
hi, if reliability is issue # 1 stick with a stock type coil  Napa has a good one. #IC21. that's what I run. Most "performance" coils are junk, made in China,  Taylor MAY be the exception. gz

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Re: Tfi coil question,
« Reply #9 on: December 13, 2015, 11:20:58 AM »
 I currently have an MSD Blaster 2 that I bought in 06. I had it on my 81 for a year or so with the resistor wire and had no issues with the coil or the ICM. The car was put to the side and I later installed it on a 65 IH Metro and used it there for about a year. I installed the 3 ohm Flamethrower in '10 on my 86 and it lasted a few months before it burned up. I installed the MSD on it with no resistor wire and thought I fried the ICM and installed an MSD Street Fire CDI. It has been on the car since '10 with the old MSD coil and runs great. I gave my "burnt" ICM to another member and it worked fine.  :o
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
1981 AMC Eagle Wagon As Seen On TV  Lost In Transmission


 

"I know he'd be a poorer man, if he never saw an eagle fly,
Rocky mountain high"  John Denver
Click for Fayetteville,TN Forecast" border="0" height="100" width="150

Offline rommel1940

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Re: Tfi coil question,
« Reply #10 on: December 13, 2015, 03:18:45 PM »
Yeah amc put that resister wire thete for a reason, I put that coil on today and test drove it, I do feel a difference in acceleration and power.voltage at coil with resistor wire is around 4 volts.That seems real low but its running better.Still waiting on my new wires, cap and rotor.was working on my car so I said well nothing better to do.My coil is a 1.4 ohm 45, 000 volt ebay chrome oil filled canister coil,  supposedly made with German parts, its 15.00 bucks shipped, I figured it was worth a try since there allmost all made over seas.Right now my csr is running better than ever so for niw I'm leaving the wiring alone, till I learn more.heck it will chrip the tires around a corner now.
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Offline carnuck

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Re: Tfi coil question,
« Reply #11 on: December 14, 2015, 01:35:12 AM »
hi, if reliability is issue # 1 stick with a stock type coil  Napa has a good one. #IC21. that's what I run. Most "performance" coils are junk, made in China,  Taylor MAY be the exception. gz

Run IC12 or the cheaper IC12SB from NAPA. Get rid of the push on connector and start every time I turn my key now! Didn't swap in my HEI yet either!
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline rommel1940

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Re: Tfi coil question,
« Reply #12 on: December 14, 2015, 07:55:27 AM »
Yeah its hardwired with ring terminals
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