Coil choice dilemma...
Thread Starter
Burning Brakes
Joined: Aug 2005
Posts: 1,164
Likes: 1
From: Europe, France
Coil choice dilemma...
Hi there,
I've got a ( new ) Pertronix Flame-Thrower Hall effect distributor triggering a MSD-6AL ignition box.
Just now, I'm using a Mallory ignition coil #29440 :
http://www.summitracing.com/parts/MAA-29440/
Maximum voltage is 55,000 V
Turns Ratio is 105:1
Peak Current is 100 mA
Spark Duration is 500 µS
But I also have a brand new ACCEL Super Coil #140001 :
http://www.summitracing.com/parts/ACC-140001/
Maximum voltage is 45,000V
Turns Ratio is 70:1
Peak Current is 300 mA
Spark Duration is 400 µs
Both coils are oil-filled.
In fact, I already tried both and they both work great, but one of them should be better than the other.
I noticed that the spark created by the ACCEL coil is fatter/thicker. This is likely caused by its higher peak current, even if the peak voltage is lower...
So, which one is better ? What is the most important factor ?
Peak voltage, peak current, spark duration, all of them together ?
I know the best way to determine it would be to dyno the engine with both coils and look at the results, but it's a bit expensive just to check two different coils...
So, if someone has experience with that, please chime in...
I've got a ( new ) Pertronix Flame-Thrower Hall effect distributor triggering a MSD-6AL ignition box.
Just now, I'm using a Mallory ignition coil #29440 :
http://www.summitracing.com/parts/MAA-29440/
Maximum voltage is 55,000 V
Turns Ratio is 105:1
Peak Current is 100 mA
Spark Duration is 500 µS
But I also have a brand new ACCEL Super Coil #140001 :
http://www.summitracing.com/parts/ACC-140001/
Maximum voltage is 45,000V
Turns Ratio is 70:1
Peak Current is 300 mA
Spark Duration is 400 µs
Both coils are oil-filled.
In fact, I already tried both and they both work great, but one of them should be better than the other.
I noticed that the spark created by the ACCEL coil is fatter/thicker. This is likely caused by its higher peak current, even if the peak voltage is lower...
So, which one is better ? What is the most important factor ?
Peak voltage, peak current, spark duration, all of them together ?
I know the best way to determine it would be to dyno the engine with both coils and look at the results, but it's a bit expensive just to check two different coils...
So, if someone has experience with that, please chime in...
Melting Slicks
Joined: Mar 2007
Posts: 2,100
Likes: 12
From: Frederick Maryland
Coils are among the most over-hyped performance parts of all. Any coil will only put out as much voltage it takes to make a spark jump across the gap. A 55k volt coil will only put out 30k volts if that's all it takes...the same as a 30k or 40k volt coil. The additional voltage rating only matters when more electrical energy is needed to make the spark jump the gap.
If you maintain your ignition system in good shape, the rated voltage really doesn't become an issue. What's more important is the coil's saturation time...the time it takes to "recharge" itself for the next shot of volts to the next spark plug.
I doubt if a dyno would show any significant difference between the two. If there is a difference, it probably wouldn't be in the rpm range you drive at...most likely at the very highest rpm's the engine is capable of. Use whichever you like best or think looks best under the hood. Both the Accel and Mallory coils have been marketed for many years and if people weren't happy with their performance they would have been discontinued long ago.
If you maintain your ignition system in good shape, the rated voltage really doesn't become an issue. What's more important is the coil's saturation time...the time it takes to "recharge" itself for the next shot of volts to the next spark plug.
I doubt if a dyno would show any significant difference between the two. If there is a difference, it probably wouldn't be in the rpm range you drive at...most likely at the very highest rpm's the engine is capable of. Use whichever you like best or think looks best under the hood. Both the Accel and Mallory coils have been marketed for many years and if people weren't happy with their performance they would have been discontinued long ago.
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I agree with the statements above. I'm betting you won't notice a difference.
A couple things, though: The coil voltage ratings are for the mechanical dielectric/insulation construction of the coil. This has nothing to do with the plug voltage.
The electrical specs are suspect, too, in that what are the test conditions for each coil? Unless you know how each was tested, how do you make sense of the results?
I'm assuming that ignition box is a CD unit. The CD storage capacitor determines how much energy is available to the coil. Outside of some minor efficiency differences, there probably isn't going to be a lot of difference in what energy quantity is eventually outputted to the plugs.
Lotsa snake oil in the ignition aftermarket.
A couple things, though: The coil voltage ratings are for the mechanical dielectric/insulation construction of the coil. This has nothing to do with the plug voltage.
The electrical specs are suspect, too, in that what are the test conditions for each coil? Unless you know how each was tested, how do you make sense of the results?
I'm assuming that ignition box is a CD unit. The CD storage capacitor determines how much energy is available to the coil. Outside of some minor efficiency differences, there probably isn't going to be a lot of difference in what energy quantity is eventually outputted to the plugs.
Lotsa snake oil in the ignition aftermarket.
Race Director
Joined: Jan 2000
Posts: 13,018
Likes: 2,262
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
Take your pic. My parts store Bosch stock replacement type coil makes 9 sec passes regularly without a wimper.
JIM
JIM
