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Screamin Eagle Performance Spark plugs

11K views 27 replies 16 participants last post by  129834 
#1 ·
I'm getting ready to change my spark plugs on a 17 RGS, which already has a Stage II torque cam and ventilator air cleaner. HD offers stock plugs for about $5 bucks each and Screamin Eagle Performance plugs for a few dollars more. Does anyone have an opinion on the Screamin Eagle plugs? They say they are designed to go with Stage upgrades. I'm really not concerned about the few bucks more that they cost. I just want to know if they actually make a positive difference.

Thanks,

George
 
#3 ·
The thing to consider on plugs is the heat range. Some spark plugs are designed to run hotter and some are designed to run cooler. Sometimes if someone is experiencing detonation or pre-ignition you can select a cooler running spark plug to help get rid of it. For what you have don't worry about spending the extra bucks on the SE plugs and just keep running the stock ones. There is absolutely no benefit you would see out of running the SE plugs.
 
#5 ·
I don't recall if the M8 motors have ion sensing like the twin cams do but I know the SE plugs and wires will mess with it.
I think that issue pretty much went away when the CanBus system came into play. I hear it's not as sensitive to the resistance changes as the old J1850 electrical system was. I also know that the ION sensing just had problems in the beginning and I think HD tried to blame it on changing plugs or wires.
 
#12 ·
I’ve tried a few of the latest and greatest plugs, including the SE, I didn’t really notice a difference. There was one plug out a couple of years ago that cost almost $30 for a set, I forgot the name......long story short they seemed to make the bike start a little faster and run a little better at first, but once they got hot......not so good.
 
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#13 ·
Stock plugs are what is recommended for my 09 CVO. I did read (think on the forum) that the standard plugs have better anti-knock characteristics than the SE plugs. I will check if I find the post I will put a link up.
 
#14 ·
I have used both and there was no difference except for cost. Also there is no reason to change spark plug often unless it just makes you happy. It's funny how people want to put new spark plugs in their bike every 20K but they won't change the spark plugs in their car/truck until they start having problems. JMO
 
#15 ·
So true , ironmark I changed mine out at almost 20k dealer parts guy thought I was crazy, told me every 5k not according to your owners manual I stated, and yes standard plugs for me too, anything else is a waste of money.
 
#17 ·
SE plugs are a joke. Just another way for the MoCo to reach deeper into your wallet.

No reason not to upgrade your plugs, especially after correcting to oil burning breather, but you can get 4 NGK iridium plugs for the price on one SE iridium plug.

M8's don't use ion sensing, they have piezoelectric sensors like most other vehicles now. Twincams can't use piezoelectric, because the noise in the rockers trips the piezoelectric sensors. The EPA demanded knock detection so the MoCo went with Delphi ion sensing even after GM and its subsid's had given up on it. Fact is, once you move off of those MoCo base tunes, you don't need it.

I've been running NGK iridium in my 11 103 since they were first swapped out @4000 miles. One set up to 40+k and a new set when I put the 110 kit on last winter. And I just run oem wires, put a new set on with the new plugs.
 
#22 ·
RA8HC Champion
My Tuner uses and recommends them in all the twin cams from stock to modified.
Available for about $2.50 just about everywhere.
 
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