Difference in ohm rating on plug wires?

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71DodgeDemon340

71DodgeDemon340

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i know it should be self explanatory but is there a significant difference between 350 ohms/ft and 40 ohms/ft plug wires? I would think the 40 ohms/ft would have less resistance and there fore conduct or let the spark travel more freely to the plug?
 
40 ohm wires are usually not that common in cars with a lot of electronics, too much RFI induction, the 350's are pretty low too but you wont tell the difference between the two performance wise. Accel's were like 600/ft.
 
I had a buddy whose Step Father was an electrical nerd. He suggested testing spark plug wire sets before buying. I did this for a few years , then started buying better stuff than the bottom shelf wires at Auto Zone.
 
Years ago we were told that the "upper limit" was 1K/ft. I've never found one that high, unless it was open.

Modern wires are a completely different ball game. Some are magnetically suppressed, and 'I guess' some of that type are not suitable for EFI applications

There are a few stories around the 'net where plug wires caused MSD and other ignitions to self/ false trigger, and in once case drove the VR nuts
 
67Dart273 said:
Years ago we were told that the "upper limit" was 1K/ft. I've never found one that high, unless it was open.

Modern wires are a completely different ball game. Some are magnetically suppressed, and 'I guess' some of that type are not suitable for EFI applications

There are a few stories around the 'net where plug wires caused MSD and other ignitions to self/ false trigger, and in once case drove the VR nuts
Click to expand...
I have always ran the low resistance MSD wires, never had a problem w/ them or had to replace them. On the 5th hotrod now. (not the same wires tho ! LOL )
 
pishta said:
40 ohm wires are usually not that common in cars with a lot of electronics, too much RFI induction, the 350's are pretty low too but you wont tell the difference between the two performance wise. Accel's were like 600/ft.
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This ^^^^

Basic electrical knowledge of Ohms law applies.
I have people argue this with me from plug wires to electronic cig vap coils. The “Ohm” is a measurement of resistance. Less resistance the quicker the energy can travel requiring less power from the sorce to complete the job. That is less effort.

On the engine performance front, your going to need a super sensitive machine to show anything. But it is there. It may not translate into anything meaningful hence why people say it is bunk. But it is less stress on the electrical parts.
 
I think the lesson here is that if I have have a car with a lot of modern electrics, then I should be concerned about what wires I am running. If not, then I can run solid core wires or equivalent without fear. My cars have always been simple ones running solid core with no RF problems.
 
There truely should be little to no difference of performance. Although I have not measured it, the voltage produced by the coil is extremely high and the resistance of the wire will have little effect on the spark produced by the plugs.
It will be enough of a spark to ignite the fuel mixture in the cylinder properly
 
As mentioned,rule of thumb was 1000 ohms/foot maximum.
 
Screw backs mom! Go for the minimum! Why waste time?
 
Seems like the focus on "resistance", blinds many of the fact there is inductance in the circuit too.

The secondary circuit of an ignition involves the ignition coil seconday winding that has inductance, redistance, and the series resistance and inductance of plug wires followed with the plug gap. The coil winding is typically the predominate factor. Prior to spark, current doe not flow, so the effect of resistance is nill. When spark happens, the plasma in the gap conducts, is has a low impedance, the gap voltage typically 50 to 100V. A portion of the stored energy in the coil primary is transfered. The spark duration, and current is related to the energy stored, and the circuit elements.

Viewing primary voltage, and current with a scope, is fairly simple. The information from that, when used with math and circuit values, answers much.

Viewing spark current, is a window into the combustion event, the current profile follows the flame burn, and even the texture of detonation. That takes a long duration spark method.

Typically enough spark is enough ... The initial trigger has high peak energy, the typical conduction that follows helps, but multi-strike is superior. Modern ignitions use multi-strike for cranking and lower RPMs, the little coils are designed for that... they are better than you think.
 
Thanks guys was just curious. I have the taylor spiro pro 8mm wires and they are 350 ohms/ft. Was thinking of swapping a set of 8.2mm taylor thundervolt wires and they are 40 ohms/ft. If im not going to gain anything im going to leave the ones i have. Or i could splurge and go with the 10.4 mm wires lol
 
Murray said:
I think the lesson here is that if I have have a car with a lot of modern electrics, then I should be concerned about what wires I am running. If not, then I can run solid core wires or equivalent without fear. My cars have always been simple ones running solid core with no RF problems.
Click to expand...



Nope. There are virtually zero (I say virtually because I don't know every ignition system out there) electronic ignitions that will tolerate solid core wires. I first tried it in 1980 and it was a nightmare.

The ONLY ignition I KNOW for a FACT that uses solid core wires and must use them is a convention magneto. The MSD mags use a suppression wire. I can tell you solid wires on an MSD mag is a disaster.
 
yellow rose said:
Nope. There are virtually zero (I say virtually because I don't know every ignition system out there) electronic ignitions that will tolerate solid core wires. I first tried it in 1980 and it was a nightmare.

The ONLY ignition I KNOW for a FACT that uses solid core wires and must use them is a convention magneto. The MSD mags use a suppression wire. I can tell you solid wires on an MSD mag is a disaster.
Click to expand...
We switched to the MSD ignition way back when they first came out, on the hemi. We had solid plug wires on it for about 1/2 a season before we found out ''u can`t do that," when we switched wires , we couldn't tell any diff . !!
 
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