Hei ignition system questions.

[Bill Chase]

When running a decent amount of overlap and higher compression on a street engine, are there benefits to using the msd 6al system with tpi hei?

Also how low of resistance plug wires can I run without having rf noise that causes problems with the radio.

Basically I want the hottest ignition I can get that is compatible with the tpi hei distributor and the best wires I can get, (up to a max of 9mm outer diameter) but not at the expense of radio interference, street car and it will have a good stereo system as well.

[rebelrouser]

You only need enough ignition system to lite the fuel air charge, more than the requirement will not make it run any better. In fact too much energy in the system may lead to problems, electricity is like water it follows the path of least resistance, if its easier to go through the plug wire than across the plug gap that is where it will go. You just need enough energy to ionize the air at the plug so the spark can jump the gap, temperature, compression, turbulence in the cylinder, and other factors determine how much energy you need. Years ago I had a buddy that purchased a wiz bang ignition system, and it malfunctioned. My buddy was bummed out that he could not race and make the first round call. I talked him into using an old single point distributor he had in his swap meet junk, we used the good coil that came with his system, and the car ran exactly the same ET as it did when the high dollar system was on the car. I have more trouble keeping plug wires from getting damaged by header heat than any issues with resistance, pick some wires and shielding that keep the wires from burning. I like the MSD, and other capacitive discharge type ignition systems, any that you pick will most likely serve your needs.


https://dsportmag.com/the-tech/ignition ... rformance/

[mag2555]

What rpm will the motor spin up to?

To help keep noise out of the power feed to the radio be sure to run a separate ground wire for the MSD right to the Battery .

[Walter R. Malik]

When running a decent amount of overlap and higher compression on a street engine, are there benefits to using the msd 6al system with tpi hei?

Also how low of resistance plug wires can I run without having rf noise that causes problems with the radio.

Basically I want the hottest ignition I can get that is compatible with the tpi hei distributor and the best wires I can get, (up to a max of 9mm outer diameter) but not at the expense of radio interference, street car and it will have a good stereo system as well.

Personally, I would add a Pertronix "Second Strike" CD addition to the "inductive" HEI.
Be certain there is enough amperage to the HEI.

[bobmc]

I ran the Moroso 8mm wire-not the ultra low resistance type with MSD 6 and .075" plug gap on my street car with no radio interference at all

[RCJ]

I installed a msd6 on a 350 sbc that made a round 330hp.It was a daily driver, I couldn't feel any change.
I had a 680hp race motor on the dyno.Took the msd off and put an HEI on it.I don't remember how much but it lost power(20hp maybe).

[Schurkey]

When running a decent amount of overlap and higher compression on a street engine, are there benefits to using the msd 6al system with tpi hei?

Yes, You'd gain a rev-limiter. Beyond that, probably not.

I had an MSD 6T on my '88 K1500 5.7L TBI. One day, it stalled. MSD died. I pulled the wiring for the MSD, went back to straight HEI, and never noticed a difference.

Also how low of resistance plug wires can I run without having rf noise that causes problems with the radio.

Depends on the construction of the plug wires.

The original "resistor" wires had high resistance, 2000+ ohms per foot, which decreased ignition "spark" current, which reduced TV-radio interference. Newer, "spiral-" or "helical"-wound wires have very low resistance, perhaps under 50 ohms per foot, BUT THEY STILL DECREASE SPARK CURRENT. They use inductance instead of resistance. Makes for great ad copy--"Low resistance plug wires" but they function just the same.

Service life MAY be improved with the helical metal core, compared to "carbon-rope" resistance wires. Or maybe not, depending on the quality of each.

Point being, "low resistance" suppression wires will be "high inductance", either method suppresses radio interference by cutting amperage delivered to the plug.

Basically I want the hottest ignition I can get that is compatible with the tpi hei distributor and the best wires I can get, (up to a max of 9mm outer diameter) but not at the expense of radio interference, street car and it will have a good stereo system as well.

You have a million choices. I've used MSD Super Conductor wires, I've used Summit "House brand" helical wires. Both are (or were) advertised as "Made in USA". LOOK BEFORE YOU BUY. As always, cheap-junk Chinese crap will be cheap junk, even if the price is high.