Spark Plugs best for the EVO 80ci

Nothing wrong with stock. I once tried several thinking my EVO would run better with a "better" plug. More complete burn, etc. Many different thoughts on this subject
It's right up there with the oil threads. Bottom line is I really couldn't tell the difference.

Yeah, I'm a fan of iridium. No real performance gains but last forever. (figuratively)

In my old girl 93, I've always used the old reliable "Champion RN12YC". Never a problem, and there cheap...

Autolite 4265

nvsteve said:

Yeah, I'm a fan of iridium. No real performance gains but last forever. (figuratively)

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You need to look deeper. True, Iridium does not offer any performance gain, but what plug does? What they do offer is some problem solving. On Harleys you can run a colder heat range to help with hot spark knock, and not have cold fouling issues. Try that with copper. And you can run them a lot longer, which is of more benefit on the M8, the others are easy to swap out. They also do better in engine that burn a little oil, the iridium tips being more resistant to deposit build up than regular electrodes.

It`s an Evo, why get complicated?

Champ or OEM work fine.

NGK iridium

'The best' - Hahaha.

'Use these plugs because they last longer' - Hahahaha

It is a harley. Regardless of which engine style or chassis platform the spark plugs are right out there in the wind. Could not take more that five minutes take the wrench out of the tool box, remove & install both plugs and put the wrench back in the box. Seriously.

How would one quantify anything as 'The best'?

I just watched an episode of "Engine Masters" on Motortrend and they did a spark plug comparison. Quantified on a dynomometer they proved that there was basically no power improvement but Iridium plugs do last longer.

Correct and as Thermo said in his comment .

Hoges said:

Correct and as Thermo said in his comment .

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Absolutely, I'm not trying to take credit but more like agreeing with Thermodyne, just like you.

hillcat said:

I just watched an episode of "Engine Masters" on Motortrend and they did a spark plug comparison. Quantified on a dynomometer they proved that there was basically no power improvement but Iridium plugs do last longer.

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That's my absolute favorite TV show; followed by Roadkill Garage. Love Dulcich's goofy ass.

I wished they'd included AC though.

joe

By far it the Iridiums from Denso.
No Iridium come close to those and Iridiums are the only plugs to use for EVOs, twinkies and M8s.

I discovered an OFF-The-BOOKS Spark Plug that runs perfectly in my EVO 1340cc engines
( if you can locate them any more = I found some on AMAZON & eBAY )
...
BOSCH Platinum+4 part number 4478
&
they don't require "INDEXING" and burn a perfect white/tan

I run them in my 1985 FXRP & 1995 DYNA Convertible

COOP
...

Gus said:

Best plugs,
for a 99 evolution Softail custom 80 cubic inch.

Maybe somebody has put up a survey in the past that might be available not sure if I've seen that?

Any case , trying to sort through all the different plug varieties copper, copper core, platinum, platinum plus, iridium,,
what's your experience and thoughts on all these variations?

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Shooty Mcbang said:

By far it the Iridiums from Denso.
No Iridium come close to those and Iridiums are the only plugs to use for EVOs, twinkies and M8s.

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You are reading too much advertisement.

Iridium plugs are certainly not the only plugs to use for an EVO, as proven by millions of miles of using standard OEM plugs by EVO owners over the past 38 years.

What extensive testing have you performed under controlled circumstances to reach this scientific conclusion?

Have you read any posts citing failures of a 5R6A or RN12YC Spark Plug?

There is no difference in performance between any plug designed for an EVO.

Homesick said:

That's my absolute favorite TV show; followed by Roadkill Garage. Love Dulcich's goofy ass.

I wished they'd included AC though.

joe

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Yeah, my brother and I watch the show and are Dulcich fans too. We both looked at each other and laughed when he first smiled with his new teeth. Most of the car TV show guys spend their new money on tat's but Dulcich got a new mouthful of Chiclets.