EI and Resisters

1up3down · May 17, 2014

Someone explain why the current range of low voltage digital electronic ignitions require resister stuff?

like resister spark plugs, resister leads...

can there be too many instead of too few resisters?

I read on an earlier thread that just one resister was required

so having both resister plugs and resister plug leads while they may work are maybe overkill

or even unnecessary

or worse yet, actually bad.....in that too much resister stuff can actually damage the coil or EI or both?

I have a Trispark with NGK resister plugs and resister plug leads....having both possibly cause failure?

tomspro · May 17, 2014

Resistance is futile.

(sorry CJ - but that is the extent of my electrical knowledge)

Hobot · May 17, 2014

its more a safety factor like too many cell phones affecting cockpit sensors and programs in air craft, but really won't or they'd all fall out of the sky near cities let alone in the radio wave intensity of air ports, so R factor is more a suggestion in case it does interfere and the least R factor to do so the better for ignition. Each R factor element, plug, cap, lead usually adds ~5000 ohm to suppress the RF ringing attenna, so much more than that can over work heat the electro box ignition components even though no static RF spikes doing anything d/t the excessive R factor. Keep your polarities of chemistry, electronics and physics straight or could let some vital smoke $ignals out.

L.A.B. · May 17, 2014

1up3down said:
Someone explain why the current range of low voltage digital electronic ignitions require resister stuff?

like resister spark plugs, resister leads...

https://www.ngk.com/glossary/8/spark-plug/R

RFI

At the moment the spark jumps the Gap it causes a high frequency burst of energy, known as RFI (radio frequency interference). RFI, as its name suggests, creates static on your radio and interference with other electronic equipment, including the vehicle’s on-board electronic control units (ECUs).

Resistor plugs were developed in the 1960s to suppress some of the spark energy, thus lowering RFI to an acceptable level. Most Resistor spark plugs use a monolithic Resistor, generally made of graphite and glass materials, to filter the electrical voltage as it passes through the Center Electrode.

Since Resistor type plugs actually “resist” some of the spark energy, non-Resistor type plugs actually deliver a more powerful spark. It is for this reason that most racing plugs are non-Resistor types. However, in most automotive applications, a Resistor plug is required for proper vehicle operation.
Use of non-Resistor plugs in vehicles that call for a Resistor type can result in rough idling, high-rpm misfire, and abnormal combustion.

Placing a Resistor within the spark plug suppresses the RFI. Without Resistor plugs in your car you can experience static on your radio as well as interference with other sensitive electronic equipment. Some later model vehicles as well as newer power sport engines must use Resistor plugs for a proper "talkback" to the electronic ignition.

1up3down said:
can there be too many instead of too few resisters?
I read on an earlier thread that just one resister was required so having both resister plugs and resister plug leads while they may work are maybe overkill
or even unnecessary or worse yet, actually bad.....in that too much resister stuff can actually damage the coil or EI or both?
I have a Trispark with NGK resister plugs and resister plug leads....having both possibly cause failure?

Unnecessary? Yes, almost certainly.

Whether 'over-suppression' actually damages a particular electronic ignition system is perhaps a question best answered by the manufacturer, but as far as I know, increasing the resistance further than necessary does reduce the spark energy.

Torontonian · May 17, 2014

Aircraft do it for necessary safety reasons not to interfere with critical systems. Your old Norton.. Do you use radios,cel phones or G.P.S. ? B.T.W. any system that interferes with the safe operation of a vehicle is illegal. This includes the wife on the back yelling that she needs a toilet but now. :idea:

comnoz · May 17, 2014

Modern digital ignition systems and voltage regulators need resistor plug wires to cut down on RFI [radio frequency interference]. These radio waves can upset the operation of the parts and even lead to failure.

Extra resistors in the ignition circuit will not reduce spark energy in any appreciable way although resistors sometimes fail so I don't like to use more than needed.

I prefer helical wound resistance plug wires and a resistor plug instead of resistor plug cap. That way the resistor gets renewed each time the plug is replaced. Jim

L.A.B. · May 17, 2014

comnoz said:
Extra resistors in the ignition circuit will not reduce spark energy in any appreciable way

On the one occasion I've tried using both resistor plugs and resistor caps together, the sparks were noticeably weaker and the engine became more difficult to start, so I'd say that at least for some ignition systems (in this case it was a BMW twin with a factory EI) doubling-up the resistance can make a difference.

1up3down · May 17, 2014

so it sounds like if you have resister plugs then having resister plug leads and/or plug caps is not a good idea
in that the plugs alone fulfill the resister need and the other stuff just weakens the spark.....?

comnoz · May 17, 2014

When you consider that conventional suppression plug wire is 10 to 15 thousand ohms per foot and many automobile plug wires are 2 to 3 ft long for a total of 35 to 45 k of resistance and then used with a resister plug for a total of up to 50K- then I don't think 6 inches of any kind of resistance plug wire on a Norton is going to affect anything when combined with a 5000 ohm plug or plug cap. Jim

tomspro · May 17, 2014

from: http://trispark.blogspot.com/2012/08/spark-plugs-and-spark-suppression-q-and.html

Q: Do I need spark suppression with the Tri-Spark ignition?
A: Spark noise is like the electrical equivalent of a Tsunami or Tornado. The electrical noise interferes with all sorts of electronic items including the ignition and charging systems so it's best to have either resistor type plugs or caps (not both) fitted to your engine to reduce the noise and keep things running smoothly. Keeps your GPS happy too!

L.A.B. · May 17, 2014

comnoz said:
When you consider that conventional suppression plug wire is 10 to 15 thousand ohms per foot

I think conventional suppressed HT wire is often nearer 2 - 5 kOhms per foot.

http://www.magnecor.co.uk/pdfs/Spec_she ... for_UK.pdf

72 ohm per cm, 2.2K ohm per ft. + 10%.

http://www.magnecor.co.uk/pdfs/8mm_elec ... ions07.pdf

98 ohm per cm, 3K ohm per ft. +/- 10%.

http://www.autozone.com/autozone/repair ... 3f802c5542

If the measured resistance is less than 7000 ohms per foot of wire, the wire is good. If the measured resistance is greater than 7000 ohms per foot, the wire is defective and should be replaced.

1up3down · May 17, 2014

the Legendary Tomspro posted:

so it's best to have either resistor type plugs or caps (not both) fitted to your engine

and that quote is from the Trispark blogspot and so it must be taken as the final word

run ONE resister and NOT more than one

I have resister plugs, therefore I should NOT have resister plug caps or leads

but the blog does not say why, only reason I can think of is that is suppresses the spark too much?

Hobot · May 17, 2014

Its not how many resistors but total resistance in the hi tension path that matters and then no definite set amount but in general 5000-ish is adequate for most our electronics. Too much resistance can lower current flow in HT leads with trade off of higher voltage needed in HT leads to make it across spark gap but which can also be enough to arc inside the brain box or over heat its potted components pushing against the R factor. In this case R factor can be thought of a shock absorber dampening, don't want so much it prevents springs coiling-uncolling fully or so little they keep on spring ringing off the road. No set recipe for a Goldie Locks optimal resistance solution but trial error per install situation. Same for carbs and cam degree's, manual setting is quite adequate but may be improved on if really trying. When I had to put a no R plug in Peel it turned her LED signals into syncopated ignition-rpm timing lights.

comnoz · May 17, 2014

High performance helical wound wire is lower resistance. Regular old carbon core wire as used on cars from the 60's to at least the 90's is generally between 10 and 15,000 ohms per foot.

http://www.popularmechanics.com/cars/ho ... ce/1272351

There is no voltage lost over a resistor wire when the voltage is needed. ie when the high voltage is required to ionize the air between the electrodes. At that point there is no currant flowing so there can be no voltage loss. Once the arc starts a very small currant will flow but once the arc is started only a few hundred volts are required to sustain the arc so the loss of voltage is of no concern.

Resistor wire will slightly reduce the amount of current flowing through the arc but it will also slightly increase the duration of the spark since the coil can not discharge quite as fast. Pick your preference. The difference is nill unless you have a very borderline ignition system in which case you should fix it.

The biggest deterrent to using high resistance carbon core wire on a Norton is the fact that the motor will shake it to death in short order. That is why I prefer helical wound resistance wire. 6 inches of it will only add a few hundred ohms resistance to the circuit and it still helps reduce RFI if that is a concern. Then add a 5000 ohm plug cap or resistor plug to eliminate the RFI. It is necessary on my bike with all the digital stuff on it. Jim

L.A.B. · May 18, 2014

comnoz said:
Regular old carbon core wire as used on cars from the 60's to at least the 90's is generally between 10 and 15,000 ohms per foot.

60's? I guess I've never seen carbon wire that old, and I certainly wouldn't use it, not that I would normally use carbon wire anyway, only copper core wire with 5kOhm caps. :wink:

http://www.auroraelectronics.com/Unders ... 0Wires.htm

Previously mentioned, RFI is reduced by limiting the current flow in the wire. This reduction of current flow also results in a weaker spark to the plugs.

jaydee75 · May 18, 2014

We know that the extreme of high resistance, open circuit, eg. kicking your bike over without plugs grounded, is bad for EI systems. So where is the point of resistance that causes damage? I don't know, but it seems like you would want to minimize resistance. If you use R plugs, R wires, and R caps, they are all in series and maybe 15k ohms total. Maybe too high? Maybe cause EI failure?

RFI? I couldn't care less about the guy next to me's radio. And since my TriSpark is enclosed in essentially a Faraday cage, I'm not worried about RFI affecting me.
So i use old school copper Packard 440 wires, standard caps, and R plugs for just a little resistance. Works fine for me.
Jaydee

Hobot · May 18, 2014

Traditional HT leads in vintage British Hot rods used the yellow black stripe "Bumble Bee" copper leads which Moss Motors and others still carry for the real snobs of restoration originality in break down prone English cars.

EI and Resisters

1up3down

tomspro

Hobot

L.A.B.

Moderator

Torontonian

comnoz

L.A.B.

Moderator

1up3down

comnoz

tomspro

L.A.B.

Moderator

1up3down

Hobot

comnoz

L.A.B.

Moderator

jaydee75

Hobot

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