Aftermarket plugs

[Advntr]

I run autolite 1163's in a 07 Ultra-big difference esp when hot with the one step colder plug.  Btw the burn pattern on the 1163's is textbook perfect.

We get a lot of blah blah blah about the bikes running hot...sure they run hotter than evo engines but so what?? They were designed to run hotter...Stop whining... Put a set of colder plugs in and go get some adventure.

[Dennis The Menace]

Oh no..more FUD for me.....

I run the SE triple platinum plug (EX12S)  instead of stock, only because I like the dual prong firing--gives me a feeling I might be getting a better spark.  I run a TMax and Doherty AC, with Bubs, but no other mods.

Am I better off with stock plugs than the SE?

Menace

[Admiral Akbar]

Resistor plugs typically have a 5k DC resistance value (+/- 10%):

http://www.ngkntk.co.uk/working/RunScript.asp?sname=Resistor+Plugs&smenu=TechSpark_2&page=171&submenu=TechSpark&p=ASP\Pg171.asp

I just measured several NGK DCPR7E,  Autolite 4164, and HD 6R12's --- they all measured in the 4.7 to 5.3k range. HOWEVER, IF the plug were to cause problems with the ion sense circuitry and or software it would be due to the plugs AC IMPEDANCE, which you cannot measure with a simple ohm meter. The AC impedance is frequency dependent and would require an impedance bridge to measure. I'd lay odds that they would all likely appear close to identical .... BWTFDIK :>)

EDIT: Fixed link

While the dielectric properties of the ceramic insulator are up is the 9-10 ER (or DK as some like to call it) range, I doubt the complex impedance has much of an effect.. A bridge will will giver you a bulk L and D but won't give you a frequency response.  It might be interest to try a plug on a network analyzer and see what you get? Not sure either will show much difference as plug constructions are about the same..  Well you would probably see something about 100MHZ up. 

It's my understanding that the ion sense circuitry is measuring the leakage to ground by applying a voltage across the secondary.

http://delphi.com/manufacturers/auto/powertrain/gas/ignsys/ionized/

Since most plugs have very high resistances to ground, I suspect it's how they age that causes problems. Cool plugs will have a shorter insulator that will have leakages to ground quicker than hot plugs with long insulators.. I suspect those having problems with after market plugs might be using one that are slightly cooler and as the deposits change the electrode resistance to ground, ion sensing takes a crap. 

Max

[ederdelyi]

>>Am I better off with stock plugs than the SE?<<

It's your wallet :>)

All I will say is that I've never been able to find any definite gain from one plug to another. If the engine is in good health and you use the correct heat range even the "cheap" plugs last a lot longer than most folks believe. That said, do whatever you feel comfortable with. The only negative with the "split-fire" type plug that I am aware of is that they have been known to shed pieces of the electrode. Not needed as far as I'm concerned and I don't use or recommend 'em.

[Dennis The Menace]

ederdelyi, makes sense to me.  If not much difference and no firing problesm with stock plug, I will likely go back.  I have 2 sets of stock in the tool chest, less than 3k on each set, so I wont have to buy any for a long time.

Menace

[FLTRI]

Ed,
To add to reasons not to use splitfire plugs, we did back-to-back in 2001 testing with 5 bikes (1 factory stock, 3 stage 1 with differnet pipes, and 1 with a high compression built 95") and found consistant 1-3hp loss with splitfires. Maybe due to possible shielding of the "extra" ground? I guess I'm not sure how the splitfire plug could do any better than a std plug considering the spark can only go to 1 ground at a time, not 2 as the propaganda would lead one to believe.
Bob

[ederdelyi]

Doesn't surprise me at all, Bob. Seems I learned that electricity and a few other things like to follow the path of least resistance ... but that's all that "science" crap that don't mean squat :>)

[jabarr]

While there is a lot of speculation about different plugs causing codes, there doesn't seem to be specific cases stated.  I had a 2006 dresser in the dealership recently that was throwing a no combustion code.  The bike was put on the dyno and all parameters were normal. Bike ran great.   Still threw codes.  The dealership had previously changed plugs(SE triple platinum), wires and coil to alleviate the problem.  I had them change the plugs to stock and guess what?   No more codes.  The mechanics didn't believe it so they reinstalled the platinums--codes returned.  Reinstalled stock plugs--no codes.  They went through this routine several times before they became believers.

[ederdelyi]

As previously stated: The ion sense setup is not perfect or bulletproof. It may not be the plugs themselves that cause the code to be thrown, rather a combination of things for that particular vehicle and the plugs are "the straw that broke the camels back". I've seen the stock plugs do the very same thing and it usually ends up that something else in the system is the real culprit ... tough to find sometimes. The safest bet will always be OEM equipment (a$$uming that their QC is up to par) but the system should be tolerant enough to work properly with components that meet or exceed OEM specs.

[FLTRI]

While there is a lot of speculation about different plugs causing codes, there doesn't seem to be specific cases stated.  I had a 2006 dresser in the dealership recently that was throwing a no combustion code.  The bike was put on the dyno what?   No more codes.  The mechanics didn't believe it so they reinstalled the platinums--codes returned.  Reinstalled stock plugs--no codes.  They went through this routine several times before they became believers.

Just another case where changing to anything but the stock sparkplugs was a mistake.

I must ask: Why on earth would anyone want to change from something that works perfectly to something they haven't a clue as to how the ECM is going to treat/look at?

Since there is absolutely no performance gain from aftermarket plugs yet very possible negative results why mess with them?

[ederdelyi]

<<why mess with them?>>

Because they can? Sorry, the Devil made me do it!

Bailiff, wack his ......!

[fxrp]

Oh no..more FUD for me.....

I run the SE triple platinum plug (EX12S)  instead of stock, only because I like the dual prong firing--gives me a feeling I might be getting a better spark.  I run a TMax and Doherty AC, with Bubs, but no other mods.

Am I better off with stock plugs than the SE?

Menace

The 'split fire' plugs are expensive and they don't work like you think. You do not get two sparks at each firing. The spark will arc to one prong or the other but not to both at the same time. I've seen it in a demonstration with my own eyes. You're wasting your money go back to a basic plug.

Paul

[fxrp]

While there is a lot of speculation about different plugs causing codes, there doesn't seem to be specific cases stated.  I had a 2006 dresser in the dealership recently that was throwing a no combustion code.  The bike was put on the dyno what?   No more codes.  The mechanics didn't believe it so they reinstalled the platinums--codes returned.  Reinstalled stock plugs--no codes.  They went through this routine several times before they became believers.

Just another case where changing to anything but the stock sparkplugs was a mistake.

I must ask: Why on earth would anyone want to change from something that works perfectly to something they haven't a clue as to how the ECM is going to treat/look at?

Since there is absolutely no performance gain from aftermarket plugs yet very possible negative results why mess with them?

Missing from your quote:  "The dealership had previously changed plugs(SE triple platinum), wires and coil to alleviate the problem."


I think I would put the "Screaming Beagle Triple Platinum" plugs squarely in the stock/OEM catagory. Sounds like an OEM quality control issue to me. I use basic NGKs and have no probelms. I don't expect performance gains but I believe that NGK, Autolite, and others are cheaper and much better quality than the HD plugs.

Paul