AR3910X Questions

[HONEYBADGERFTW]

I've searched the forum and haven't found the answer so I'll ask, is the AR3910X spark plug ok to use on a predator 212 non-hemi, with GPS intake, .038 main jet, and open exhaust header? Or is there a "better" plug? I'm aware that it's an opinion based question and will get mixed answers, but any info is helpful. Thanks

 

[65ShelbyClone]

The main, and perhaps only reason anyone uses them is because they slightly increase compression in kart classes where the head can't be milled. It's also a very cold plug and will be more prone to foul in a general purpose application. Those class karts run WOT almost all the time.

My suggestion would be to use an NGK like the Hondas come with or an equivalent. It's 300% cheaper and works just as well or better.

 

[Joe-405]

I tried the 3910x and the regular ngk. Ran like crap with the 3910x and ran flawless with the regular ngk. I’ve tried them in 3 different engines also and results were the same.

 

[HONEYBADGERFTW]

That's the NGK BP6ES, correct?

 

[Joe-405]

I use the BPRxES plugs on all my stuff.

 

[HONEYBADGERFTW]

What's the difference in BPxES and BPRxES?

NGK 7131 BPR6ES is what you're referring to, right?

---------- Post added at 01:26 PM ---------- Previous post was at 01:15 PM ----------

Nevermind, found it:

From NGK
Q: When should I use a resistor spark plug?

A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.

 

[65ShelbyClone]

"B" means it has a 14mm thread with a 13/16" hex.
"P" means it has a projected tip.
"R" indicates a resistor if present. No "R" - no resistor.
"6" is the heat range. Higher number = colder plug. Heat range span is 2-12.
"E" represents 19mm (3/4") thread reach.
"S" is for copper core construction.

You don't have to use a resistor plug, but they are easier to find and won't cost any performance. Non-resistor plugs are more useful with very high power racing ignitions that push a lot of current through the plug.

 

[HONEYBADGERFTW]

Awesome info, thanks again!