acadian
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- Mar 5, 2010
- Messages
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With a dual output (dual tower) single coil, one spark fires from ground electrode to centre electrode, and the other spark fires the other way from centre electrode to ground electrode.
So for these coils, the precious metal tip on only one surface will only be beneficial on one side of the bike.
I like Densos, as I have a concern for the NGKs and Champions being counterfeit.
The VW22 has an iridium centre electrode and platinum ground electrode, so to me is a good candidate for dual output single coils.
The IW22 has an iridium centre electrode and nickel plated ground electrode (same as plug housing) so is ideal if you are running two coils. Perfectly fine for a standard two coil setup.
The other solution would be to swap plugs from left to right whenever you take them out for cleaning or inspection.
Denso have started doing a twin tipped iridium plug (they call it the TT) but it is not yet available in our heat range.
I also checked NGK a while back - looking at their double platinum and the new ruthenium plugs, and they didn’t have a suitable plug for our bikes at the time.
This is not a major problem, it’s purely sweating the small stuff.
But I do think it’s good for people to understand how their ignitions work and that if you have selected and paid extra for precious metal plugs (like iridium or platinum) believing there is a benefit of longer service life and slower electrode erosion, you are made aware of how a dual tower single coil works and that you may be foregoing any benefit.
I know several very reputable companies that ship the NGK ‘R’ plugs as part of their single coil packages.
This has nothing to do with wasted spark ignition, where you get a firing plug on both sides whether you are on the combustion stroke or not.
That’s just the behaviour of most electronic ignitions versus standard points where you only get a spark on the cylinder that is on the combustion stroke.
This is great info, Denso's not available locally here and are CRAZY expensive online. I'm running iridiums now but even they are pricey, so I just ordered a box of plain old copper core BPR7ES for $30, will be switching back