E 3 Spark Plugs
Elite HDF Member
Joined: Jun 2006
Posts: 3,572
Likes: 5
From: Templeton California
I looked into this a few months ago and I found several Harley owners had tried the E3s and many ended up taking them back out.For various reasons some said it threw a code on their FI others said they started out running real well and ended up not so good after a few months.I ended up going with Denso irridiums and have no complaints although I can't honestly say they do anything the original NGKs wouldn't do.
I tried them for a while on my '01 FXD, no problems or obvious increase in performance. Went back to the Screaming Eagle double platinum because they seemed to make it run better when cold. The enrichener (carburated bike) could be pused in sooner without engine hick-ups. Using Autolite Iridiums (XS4164) next year.
Road Warrior
Joined: Apr 2010
Posts: 1,739
Likes: 10
From: Suffolk, England
Three observations on plugs...
There is a huge amount of bullshit and snake oil from the plug makers. Claims are never repeatable independently on the dyno.
You might get some slight improvement with stupid-price plugs on a race machine but you will see zero difference on a Harley. So don't throw you money away.
Since about 2008, Harleys (except Sportsters) have been fitted with an anti-knock system that works by measuring the resistance through the coil, the plug leads and the plugs. Fit non-stock parts here and there's a good chance you will will disable this system. You might either have no anti-knock system or else one in permanent operation. Neither is good for the long-term life of your engine.
There is a huge amount of bullshit and snake oil from the plug makers. Claims are never repeatable independently on the dyno.
You might get some slight improvement with stupid-price plugs on a race machine but you will see zero difference on a Harley. So don't throw you money away.
Since about 2008, Harleys (except Sportsters) have been fitted with an anti-knock system that works by measuring the resistance through the coil, the plug leads and the plugs. Fit non-stock parts here and there's a good chance you will will disable this system. You might either have no anti-knock system or else one in permanent operation. Neither is good for the long-term life of your engine.
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Outstanding HDF Member
Joined: Nov 2010
Posts: 2,250
Likes: 36
From: Montana
I used E3's in my 2005 heritage and it made a big difference in how smooth the carburetor ran at higher altitudes. installing a mikuni carb and good cam made the most difference in power , along with a dyna 2000 ignition. (Ah yes the dark ages some times I miss them) .
As has been stated by lots of other posters I have stayed with the stock plugs on the EFI harley and it runs just fine. On EFI bikes I don't think spark plugs play a big enough deal to use anything but stock . For more HP a stage 1 , cam or big bore would do a better job.
As has been stated by lots of other posters I have stayed with the stock plugs on the EFI harley and it runs just fine. On EFI bikes I don't think spark plugs play a big enough deal to use anything but stock . For more HP a stage 1 , cam or big bore would do a better job.
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Three observations on plugs...
There is a huge amount of bullshit and snake oil from the plug makers. Claims are never repeatable independently on the dyno.
You might get some slight improvement with stupid-price plugs on a race machine but you will see zero difference on a Harley. So don't throw you money away.
Since about 2008, Harleys (except Sportsters) have been fitted with an anti-knock system that works by measuring the resistance through the coil, the plug leads and the plugs. Fit non-stock parts here and there's a good chance you will will disable this system. You might either have no anti-knock system or else one in permanent operation. Neither is good for the long-term life of your engine.
There is a huge amount of bullshit and snake oil from the plug makers. Claims are never repeatable independently on the dyno.
You might get some slight improvement with stupid-price plugs on a race machine but you will see zero difference on a Harley. So don't throw you money away.
Since about 2008, Harleys (except Sportsters) have been fitted with an anti-knock system that works by measuring the resistance through the coil, the plug leads and the plugs. Fit non-stock parts here and there's a good chance you will will disable this system. You might either have no anti-knock system or else one in permanent operation. Neither is good for the long-term life of your engine.