spark plugs

[kartboy63]

we run SA pred on methanol and we use 3910x plugs but would a hotter plug be better, I hear the 3910x is a cold plug and what would be a better plug

 

[zastro]

That is a hot. Plug compared to a Ar3932, I like the Autolite 3924 they are a great all around plug.

 

[bob58o]

I was just looking into this.

If the 3910x is same heat range as the 3910, I found this....

"Autolite Racing spark plugs feature a cut back ground electrode, anti-corrosive nickel plating, and large ground electrode for better heat transfer. Heat range needed with Standard tip or Power tip Coldest."

^This is for the AR3910 (not specifically the AR3910x)

If you look at the AR3911...
It is "Colder" not "Coldest"

3910 is COLDEST
3911 is one range hotter, but still COLDER

Autolite seems to go down in heat range as the last number decreases. AR3911 is hotter than AR3910.

I'm running 100 octane with 11.1 : 1 CR with the AR3910X and tried a plug reading. Not sure how to read these plugs? It looked wet, like gas not oil. I want to try the AR3911?

This chart leaves some confusion as well.
http://static.speedwaymotors.com/pdf/RacingHeatRange.pdf

 

[W5R]

To check these plugs you have to make a pull to wide open throttle and cut off the engine while it is wide open, then check the plug. If it is allowed to idle down at all, you will not get a reading on the plug