plugs? : V-Twin Forum: Harley Davidson Forums

113DELUXE · 09-04-2007, 07:14 PM

what plugs would be reccomended for a 113

Totenkopf · 09-04-2007, 07:48 PM

Quote:

Originally Posted by 113DELUXE

what plugs would be reccomended for a 113

NGK standard plugs work great for us. DCPR7E for standard heat range and DCPR8E for one step colder, DCPR9E for two steps colder. I'm using 8E's on the street now.

Hillside · 09-05-2007, 04:42 AM

NGK's are the only ones we use/reccomend. The Iridiums are some of the best you'll ever buy. Seen their worth on the dyno more than several times.

DEW2112 · 09-05-2007, 05:39 AM

Quote:

Originally Posted by Totenkopf

NGK standard plugs work great for us. DCPR7E for standard heat range and DCPR8E for one step colder, DCPR9E for two steps colder. I'm using 8E's on the street now.

Tote, Are you using the DCPR8E on your 95" Twinkie?

Totenkopf · 09-05-2007, 06:22 AM

Quote:

Originally Posted by DEW2112

Tote, Are you using the DCPR8E on your 95" Twinkie?

Yessir! Love'em, best plug I've used yet. I did notice my motor responded nicely to one step colder in heat range and has not fouled them out. In my small block Chevy racing days, I used to use like J-4's with 12:1 compression on the street. They would work great for a couple of days but then had insufficient heat to burnoff deposits. I was constantly changing plugs because I was addicted to the small bump up in performance.

I've tried the Autolites MP4164 but had bad luck with varying electrode heights, Stock H-D plugs which aren't bad, the Double Plat's which are okay too, I don't believe in Splitfires, and also don't believe in "Million Dollar" spark plugs for street motors.

I like: cheap, works great and plentiful.

DEW2112 · 09-05-2007, 09:40 AM

Thanks Tote, I will give them a try.

113DELUXE · 09-06-2007, 03:35 PM

what benefit would i get from running a colder plug if any

Totenkopf · 09-06-2007, 04:35 PM

Quote:

Originally Posted by 113DELUXE

what benefit would i get from running a colder plug if any

A spark plugs heat range is determined by, among other things like design and materials, the amount of protrusion the electrode tip is into the combustion chamber. A minimum amount of heat is needed to keep the tip of the insulator clean enough to not foul out and cease working. It also has to be low enough in temperature that it does not cause pre-ignition by glowing orange hot. Something like, between 500C and 800C is the right range. What I've noticed is that by experimenting with different heat range plugs, you can see what combination your engine likes with the amount of fuel you are getting and the spark advance timing in relation to the amount of protrusion into the chamber and the resultant kernel of flame that starts from the spark gap and then extends out to a flame bubble that finally goes bang in a combustion chamber, hopefully reaching peak pressure around 16 - 18* ATDC. All these things interact and play together to give different results and through experimentation, you can figure out what is right for your situation.

DEW2112 · 09-06-2007, 05:48 PM

I will be experimenting with the DCPR8EIX this weekend.

angelflights · 09-06-2007, 06:52 PM

Jesus, I love this forum.

Totenkopf · 09-06-2007, 07:06 PM

Quote:

Originally Posted by DEW2112

I will be experimenting with the DCPR8EIX this weekend.

Try the plain old DCPR8E first. Keep the cost of the experiment down, they should be under $2 each and set the gap at 0.040". Buy a set of 7E's & 9E's also and see how those react too. The DCPR7E is the standard heat range. Please report your findings, run them for awhile and see how they do.

nc-renegade · 09-06-2007, 07:56 PM

Quote:

Originally Posted by Totenkopf

Try the plain old DCPR8E first. Keep the cost of the experiment down, they should be under $2 each and set the gap at 0.040". Buy a set of 7E's & 9E's also and see how those react too. The DCPR7E is the standard heat range. Please report your findings, run them for awhile and see how they do.

I just picked up a set of the DCPR8E's today and plan to experiment with them tomorrow. Thanks for the tips!
Regards,
NC

Totenkopf · 09-06-2007, 08:17 PM

by the way, I failed to mention that we have been racing these NGK plain old plugs for years. In the current Twin Cam Pro Mod, we have dual plug heads and use a combination of 8E's and 9E's in each head. I have used a ton of these in this motor and they never fail and are very consistent.

In the Pro Gas big twin motor we use the NGK BPR6ES-11 and BPR7ES-11. One step and 2 steps colder than standard. The BPR5ES-11 is the standard heat range.

HDWRENCH · 09-07-2007, 08:00 AM

Tote,

I checked the 4164 we have been using and found no problems with them. HMMMM I will watch for that. We like the autolight as well the NGKs work as well.

klondike · 09-07-2007, 08:57 AM

I run Iridium in my 96" bagger and have them in since last year early in the season. Pulled them last week and was surprised as hell to note that the rear plug looked exactly like the day I put it in. I mean exactly. If the threads weren't dirty you would swear it was new. The front plug had just a tiniest bit of brown on the electrode. Perfect looking but not new looking like the rear. Gapped at .040" and just about 12k miles on them, I am sold on them. keepem sharp