Resistors in spark plugs?

[BASS-TREBLE]

Went to grab some plugs from Repco for the fizzer today, need NGK DP8EA-9, they only had DPR8EA-9

The R standing for resisitor

Looking on google it sounds like the 5ohm resistor is there to suppress ignition noise, http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqresistor.asp

Seems like a good idea but are there performance issues? Such as a smaller spark?

Get the R ones or keep searching?
I can wait till bike shops are open on monday but would still like to know of any effects.

[Henk]

Throw the resistor plugs in. You won't notice the difference.

[p.dath]

Why would ignition noise on a bike be a problem? Is it interferring with your neighbours radio or something?

[CookMySock]

Why would ignition noise on a bike be a problem? Is it interferring with your neighbours radio or something?It might interfere with electronics on the bike itself, ECU, hotgrips controller, satellite tv, etc.

I thought the resistor was more about making the spark length longer. Not sure about this without studying up more on it.

Steve

[p.dath]

It might interfere with electronics on the bike itself, ECU, hotgrips controller, satellite tv, etc.

I thought the resistor was more about making the spark length longer. Not sure about this without studying up more on it.

Steve

His bike is 20 years old ... I couldn't imagine it having electronics that flash. :)

[YellowDog]

Yep, I believe that is all it is. Without the 'R' some will get a crackle on their receivers.

I guess it could affect the ECU, but I wouldn't have thought so.

The size of spark is down to you setting the gap right.

[p.dath]

It might interfere with electronics on the bike itself, ECU, hotgrips controller, satellite tv, etc.

I thought the resistor was more about making the spark length longer. Not sure about this without studying up more on it.

Steve

You are the master. :Punk:

http://www.ultralightnews.com/enginetroublshooting/resistorcapsandplugs.htm

"This reduces current flow in the spark and it takes quite a bit longer until the energy in the coil has expelled itself via resistor and spark gap. This results in a longer spark. However the spark is weaker due to energy loss in the resistor."

[nosebleed]

Looks like Asked + Answered.
Surprised no-one pointed out the "R" for Racing tho.
Chuck the "R"s in if thats what they got.

Signal noise would possibly interfere with any 'comms' equipment you run.

[CookMySock]

http://www.ultralightnews.com/enginetroublshooting/resistorcapsandplugs.htm

"This reduces current flow in the spark and it takes quite a bit longer until the energy in the coil has expelled itself via resistor and spark gap. This results in a longer spark. However the spark is weaker due to energy loss in the resistor."Thats interesting.. Yeah I have never seen a scientific approach to it like that before.

Maybe the R plugs would not be suitable for CDI ignition, since CDI gives a very hot but short spark, whereas TCI gives a longer duration spark. My guess is, the CDI isn't really capable of having its spark lengthened by a resistor - different story if it was TCI.

http://www.jetav8r.com/Vision/IgnitionFAQ.html
http://www.google.co.nz/search?q=cdi+tci+ignition

Steve

[speedpro]

Lets say the output of the coil is 20,000 volts and the current is .02A or 20mA. The 5 ohm resistor will drop the voltage .1 volts, so yeah the voltage at the gap will go from 20,000V to only 19,999.9V.

Now if he was running a Super Mag with a 20A secondary that little resistor would be a problem, not because of the voltage drop, 100V in this case, but because of the power developed in the resistor itself - something along the lines of a 1 bar heater(2Kw).

[CookMySock]

a Super Mag with a 20A secondaryMein gott!! 20A and 20KV ? Thats a fooken lot. How is that possible?

Steve

[speedpro]

I have no idea but they are one mean bit of kit. They will set fire to any mixture in any conditions. I think the smaller ones used to need 30hp or so, unsure what's reqd to turn these.

[BASS-TREBLE]

Thats interesting.. Yeah I have never seen a scientific approach to it like that before.

Maybe the R plugs would not be suitable for CDI ignition, since CDI gives a very hot but short spark, whereas TCI gives a longer duration spark. My guess is, the CDI isn't really capable of having its spark lengthened by a resistor - different story if it was TCI.

http://www.jetav8r.com/Vision/IgnitionFAQ.html
http://www.google.co.nz/search?q=cdi+tci+ignition

Steve

The FZR does have a TCI so I guess it would be all good.
Turns out they only have 2 in stock so I'll just wait till tomorrow to get em from a bike shop.

[RDjase]

Went to grab some plugs from Repco for the fizzer today, need NGK DP8EA-9, they only had DPR8EA-9

The R standing for resisitor

Looking on google it sounds like the 5ohm resistor is there to suppress ignition noise, http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqresistor.asp

Seems like a good idea but are there performance issues? Such as a smaller spark?

Get the R ones or keep searching?
I can wait till bike shops are open on monday but would still like to know of any effects.

The RZ350 uses resistor plugs so there is no interference with the YPVS power valve contoler (very similer to EXUP unit) Yours wont be EXUP model from memory , they were 88 or 89. Have a look in the plug listing book and see if they have a different listing between EXUP and your model

[Pussy]

Most, if not all, new bikes have resistor plugs in them. They don't reduce performance, and keep the neighbours happy!
I have swapped the stock plugs on my bike (NGK BPR9ES) with iridium ones (NGK BPR9EIX). They seem to give a "cleaner" spark, and last longer