High Output Coil

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TF360

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Do aftermarket high output Coils have any disadvantages. I have a 74 Duster with Electronic ignition-orange box and Mopar performance Dizzy. If I use a "better" Coil will it actually run better and not cause any issues?
 
Higher output coils are for use with higher compression engines. As cylinder pressure goes up, it takes more amps to fire the plug. If you have stock or slightly elevated compression, it's really of no benefit to run a high output aftermarket coil.
 
The term high output coil is not well defined. There are canister coils with higher turns ratio for 40-45 kV output, yet still have primary resistance of 1.5 Ohms. They would work with the stock electronic, but as RRR says little benefit.

There are Ford TFI style e-core coils in fancy extruded aluminum mounts, they pack more power, with improved magnetic circuit, and more optimum lower turns ratio. They have a lower primary resistance, only 0.4 to 0.5 Ohms, with a standard ballast, the coil current will likely exceed the stock ignition capabity, and ECM may fail. If you want to use TFT or low primary resistance coils, best to use HEI conversion, or ignition with active dwell control.
 
RustyRatRod said:
Higher output coils are for use with higher compression engines. As cylinder pressure goes up, it takes more amps to fire the plug. If you have stock or slightly elevated compression, it's really of no benefit to run a high output aftermarket coil.
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about what compression level, or dynamic compression level would you say a high output coil would be necessary? just a guesstimate for kicks
 
might help a little IF it is compatible with the orange box...but only if. The factory coils fired some fairly wide plug gaps in the late 70's so I believe they work extremely good.
 
UDUST81 said:
about what compression level, or dynamic compression level would you say a high output coil would be necessary? just a guesstimate for kicks
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You can look at what the factory used to get a good idea. Until the compression got above 11 you still saw stock style coils. There were some dual point distributors with lower compression stuff, but the coils were pretty much stock.

The Max Wedges are a good example of early high output ignitions. They used a transistorized control unit.

I would say anything with more than 170 PSI cranking pressure might show some benefit.
 
my motor should be about 190 cranking psi so guess i better start looking into it lol thanks rusty!
 
not to hijack the thread but ive been kinda toying with the idea of going for the whole late 70s early 80s street machine look, but modern performance, and always thought the accel super coil with yellow wires would help pull that look off.... any opinion on the accel super coil? junk? good? the guy i bought my tranny from seemed to be real high on them
 
They are good coils......provided you use good wires with it.
 
P4120889;sq box Supercoil. Been using it almost since day-1, in early 2000s. Goes to well past 7500, firing .045Plus gaps, through Jacobs wires(anybody remember him?) BTW my Champion Coppers have been in there since around 2004. They went in at .045. I have no idea what they are at today.I take 'em out now and then, when I check my compression; 10.7/1, or so. Maybe a tad more.
 
I have a blaster 2 coil on my car with factory electronic ignition and I don't notice any difference either way. It's just what I had laying around and it works
 
If you have ye orange box I wouldn't worry about it.

But just think of how hot the ignitions are on a modern econo box car.
 
i was checking the engine over one time and noticed a plug wire pulled back
not even making contact with the plug.I had removed the plugs a couple
of weeks earlier just to check them.
....but i had been driving like this for some time and there was never even a "miss".
This was with an auto parts store black 20kv coil and standard 7mm wires,but everything
was new.
 
The Coil I was looking at showed .700 ohms and 45,000 volts. To much for system for ECM?
 
Just because it says 45Kv does not mean it will put that out all the time. Coils are kindof self adjusting. If circumstances in the chamber are such that it only requires 20Kv, then that is what the coil will put out. If it requires 30Kv in a different circumstance, then it will put out 30Kv. And so on.The coil only puts out what it needs to, to initiate the spark and push it across the gap,under whatever the chamber conditions are.
Some things the require only modest output are; small plug-gaps,specialty plugs,and maybe cruising. Some things that require a little more output are;lean-runing,modest acceleration,and higher compression.And full-load,full power acceleration wants the maximum.
But to quote Smokey Yunich; "I think 20,000 volts is actually enough--but what an ignition really needs is a long spark duration--and high amperage."
Enter Capacitor Discharge Ignition.And multi-spark.
But for most of us with modest output engines, and reasonably close AFRs,the typical HO stuff works.
 
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AJ/FormS said:
But to quote Smokey Yunich; "I think 20,000 volts is actually enough--but what an ignition really needs is a long spark duration--and high amperage."
Enter Capacitor Discharge Ignition.And multi-spark.
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I totally agree that an engine need long duration and reasonable spark current, but a CDI ignition has about 1/20th of the duration of an inductive ignition, that is why they need multi-strike.
 
Yeah and with multi strike, it's hard to lose spark due to a crappy tune,er difficult tune,in that range during which the multi-strike is active (usually sub-3000 rpm). I suppose that is why it is so popular among the big-cam crowd.If the first spark don't light it,there's 19 more behind it, and one of them will surely light it off.
The biggest cam I have run was the 292/508/108, and it was fine with the sq-top Accell. It says not recommended for over 6500.......but..... mine goes 7200 all the time.It's rarely hung out there for more than a few seconds atta time, so I think that coil doesn't know how fast the engine is turning,lol.

I had a Blaster on a stock 340, back in the 80s. It seemed to work ok.
I had an Accell round-can on a 340 back in the 70s. It seemed to work ok too.
I had a Jacob's CDI and E-core on my current 367 for a short time,until it puked. Switched to the Accell at that time, no difference. When I got my Jacobs back from the manufacturer, I left it in the box.That unit had cost me a couple of tow jobs, and I had lost faith in it.
 
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TF360 said:
The Coil I was looking at showed .700 ohms and 45,000 volts. To much for system for ECM?
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The lower resistance coil will increase peak coil current from about 5A to 6.7A, a 33% increase. It is hard to determine, depends on many factors and operating temperature. The peak voltage seen by transistor may also increase at time of discharge, together the transistor sees additional stress. Time will tell.
 
Ok, so I bought a Accell coil. Put it on and car seems to idle a little better. I noticed when I took it out of the box it was a little oily. I hope it was not leaking. I don't know if it was a corrosion protectant oil or not.
 
TF360 said:
Ok, so I bought a Accell coil. Put it on and car seems to idle a little better. I noticed when I took it out of the box it was a little oily. I hope it was not leaking. I don't know if it was a corrosion protectant oil or not.
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There may be a screw in the top terminal, it might have a o ring seal, it might be loose. Not sure what they are doing these days. A leaking coil is not good.
 
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