I need schooled on spark plug wires with regard to ohms with MSD ignition. I’ve been running the Taylor 8.2 mm wires that have 40 ohms per foot. Others sell higher ohm rated wires. Which is better??????

I'm not your guy for a deep dive on things like ohm readings, etc., but I can tell you the Firecore wires I bought are the best wires I've had on this car!

We've run Taylors (no real issues there), MSD and standard parts store wires and these work better and fit better than any of those.

Good spark is critical with a nitrous car and we've never had a single issue.

Another vote for Firecore wires.

Okay, but my question has to do with the ohm ratings. Why is a low rating better than a high rating? Which is better for an MSD ignition? Also, where to get Firecore if they are so good??What ohms per foot do they have??

I use Moroso spiral core wires and have for years. The set on my duster are 8 years old and raced weekly during the summer. I like to make my own wires and bought the proper tool to do so years ago.

Ohms isn't the most important thing for plug wires since you're dealing with a lot of volts. Especially with a CD ignition, or with EFI. Buy Firecores and don't worry about the ohms.

Ohm’s are a measure of resistance, which takes me back again to my question. Which is better, more ohm’s or less? And Why? Again, if Firecore is that good, where do you buy them and what is the resistance of them???

Less OHMs is better , it’s lower resistance and transfers the spark better .
Another vote here for Firecore, they will custom make your lengths and the customer service is top notch .

For your application it doesn't really matter. EFI engines, or any computer controlled engine will need low RF noise wires and low noise is more important than ohms per foot. If your Taylor wires are working okay then keep them. If they need to be replaced buy some Firecores.

As stated less Ohms are better at voltage transfer through the wire. The spark plug wire has one crucial job: to deliver the high voltage from the ignition coil or distributor to the spark plug.

When spark plug wire resistance is too high, the spark plug won’t receive enough voltage to create a strong spark..

Spark energy travels from the ignition coil or distributor through the spark plug wire to get to the spark plug, which is why the plug wire is also called an ignition wire or coil wire.

Now, imagine the plug wire is a water hose, and the spark is the water running through it. Resistance would be like sand in the hose, impeding the water’s flow.

Lower resistance means more spark energy from the coil reaches the spark plug to ignite the air-fuel mixture in the cylinder. And the converse applies with higher resistance.

The distance traveled also matters. So, spark plug wire resistance is measured in ohms per foot. A high resistance wire can measure around 5,000 ohms per foot, while a low resistance wire can easily fall in the 2-digit ohm per foot range.

Here are some examples of plug wire resistance per foot:

Copper core wire: 1-6,500 ohms
Inductive wire: 650-2,500 ohms
Carbon core wire: 3,000-7,000 ohms

How To Test Spark Plug Wire Resistance

Measuring the spark plug wire resistance is pretty straightforward. You’ll need an ohm meter or digital multimeter (set to measure ohms).

With the engine off, here’s how:

1. Detach the sparkplug wire at each end — from the spark plug connector and ignition coil (or distributor) connector.

2. Check your owner’s manual for your plug wire resistance range — it’ll be in kiloohm (k ohm). Multiply the wire length in ohms per foot (if your wire is 2 feet long and the manual requires 15-19k ohms per foot, you’d want a measurement of 30-38k ohms).

3. Set the ohm meter to the nearest setting larger than the required resistance range (e.g., for a 15-19k ohm range, set the dial to “20k”).

4. Touch the ohm meter leads to a metal center at each connector end of the spark plug wire, and note down the reading.

5. Compare the ohm meter reading to your required specification.

Higher readings mean too much resistance in the ignition wire, and you should probably get a new wire. Even if the spark wire meets specifications, you should still check it for physical damage and voltage leaks.

As other have stated, get the Firecore Wires!

You guys try to make everything so complicated. Lol.

Agreed?
I’m not the brightest light bulb n the box, but I’m not the dimmest either. No one has answered my question out right. What ohm wires for an MSD ignition?? I’m with the lower resistance the better but not a solid core wire. What
is the resistance of the Firecore wires??? The Taylor’s that I use are 40 ohm’s per foot. I’m not looking to change unless I can be persuaded by good info. Thanks for all the input.

Which MSD box are you using? A street and strip 6 or one of the race 7 boxes?
It depends on which box you are using to set the plug gap at the best width
As far as ignition wires and spark plug type, resistors or non resistors, will have a big part to do with when the coil will fire at which voltage level, higher resistance will make the coil fire at a higher voltage level.
I have tested spark plug gap at the races to find out how much gap is to wide at WOT above 5500 RPM, which most of the MSD race boxes stop multi firing the plugs around 5200 RPM
The later made 7 boxes need resistor wires to work properly to avoid misfiring above 5200 at WOT
I found that out the hard way a long time ago using a set of stainless steel core early Moroso race wires, they work fine on the older D.C. internal voltage 404 boxes but not so much on the later A.C. internal voltage 7 series race boxes
Don't forget to measure both the spiral wound outer stainless steel wire resistance as well the internal graphite coated nylon conductors on the spiral wound race type wires that Moroso and other HP wire companies offer

hi

i have had good luck with using spiral core accel or Moroso .

6 AL digital is what I’m running. I still want to know the best ohm’s of wires to use. My plugs are gapped at .043”. I’m having no issues with the engine pulling over 6800 rpm. Just curious as to what I may be missing if anything with the wire ohm’s.

The MSD six boxes won't make as much voltage as the 7 race boxes will when stressing both of them to their limits. You only need as much voltage for each firing pulse to jump the gap and fie the plugs, not jump out of the wires or boots to ground.
I would use what you're running now, plugs, wires and gaps, with good success
if it ain't broken, don't fix it
You could test wider plug gaps at .003 to .005 increments to find out what is too wide for your ECO box and wire to work well with
I think your plug gaps are great now

The wires, plugs, and coil are all part of an electrical circuit that has to be studied as a whole,
including the important “stray” capacitance that is there even when there are no “real” capacitors to be seen.

If you want to simplify - the more resistance in the wires or plugs the longer the “burn time” during which the spark goes on.
A longer “burn time” is good, even if the spark is not as quite as bright.
A longer slightly less bright spark is more likely to get combustion of the gasoline going successfully,
than a shorter time bright spark.

Individual cylinder misfires are a horsepower killer.

1960s ignition systems in new factory condition still had 3% to 5% individual cylinder misfires near redline rpm.
Modern coil-on-plug ignition systems with iridium spark plug tips still have about 1% misfire near redline rpm.

Racers should keep in mind that the next cylinder cycle after a misfire the cylinder will now have higher percent air and fuel mixture due to no exhaust carrying over and DETONATION is more likely.

A single severe detonation ruins your day, week and month.

More ohms of resistance also reduces the “wasted energy” that leaves the wire as a radio wave and creates buzz in the car radio - or in the worse case “cross fires” to another ignition wire. Probably ten people know about this reason for ohms in the ignition circuit than for the one person who is aware of the “burn time” affect.

Coil on plug systems are now near universal on new engines because they can give longer burn time plus go to much higher RPM before percent misfire increases.
Same with special alloy sharp tip plugs.

Just to add to the above.
With electronic ignition, data logging and EFI the best spark plug wires do have a higher resistance to reduce RFI and EMI, this is also due in part, to the core being longer as they are helically wound which also helps with suppression. Some spark plugs have a resistor built into them for better RFI / EMI suppression and are recommended for use by OEM and lower end ignition systems.
The larger the gap at the plug, the higher the voltage has to build up to jump the gap, the higher the interference. If you have a high o/p ign system you will likely need higher resistance plug wires (typically 50 ohms per foot). In a nutshell, the best plug wire is what your ignition manufacturer of choice recommends.
Coil on plug has an advantage over single coil as each individual coil has more time to allow the voltage to decay before it fires again, allowing for a higher voltage spark at high rpm.
HTH's
EDITED

I was wondering about plug wire recommendations when I saw this thread pop up. Time to replace my old MSD 8.5s and was looking at a new set of those or Moroso Ultra 40s. Wasn't considering Firecore 50s cuz I build my own wires so that I can run ceramic plug boots where needed due to burning issues.

MSD and Firecore are 50 ohms/ft
Moroso ultra 40 are 40 ohms/ft

Mancini sells Firecore but if you just go to firecoreperformance.com
You can buy direct.

Less ohms the better-but there’s other things to consider RF/EMI suppression is
a big one in cdi type. Essentially noise suppression from the wire that can have
an effect on other electrical components. Too long to type here.

That being said I’ve run Ultra 40’s, MSD, and Firecores for the past 15yrs. None
have ever given me a problem and move ever had a better et vs another. I like the
plugs on the Firecore and Moroso the best.