Projected type plug or non projected type

[red1993gsallmt]

BPR7ES vs BR7ES which plug type would let you run more timing/boost on pump gas? Ive heard projected type puts the electrode further into the cylinder to help with preignition, but non projected lowers compression. what do you guys think

 

[JayRolla]

Projected is what is normally used. I use non projected. Lots of people on the dsmlink forum has posted results of lower knock counts just switching to non projected. Usually used in marine applications. Its all I ever use now.

 

[diambo4life]

I run BR8ES in mine all year round.

 

[turboglenn]

Another here for non-projected plugs, br7es and br8es depending on the boost and if i'm running the n2o or not.

On e85 i seem to eat plugs so i change them quite often (about once every month or 2)

With projected plugs i get more detonation showing up on my J&S, slightly less with the non-projected.

the theory is that the projected ones stick out in the cylinder and become a hot spot to pre-ignite the fuel/air mix before the plug actually sparks