Ok, I'm using BR10EIX plugs all around and took them out to check how they were. Don't remember the miles on them, but they were replaced about a year or so ago and I don't drive the car much. I have hks twin power ignition.

-they all had some deposits on them, not too much, no carbon or oil

-the leading were more worn than the trailings

-the REAR leading was the most worn of all (tuning?)

-I cleaned and regapped them to 0.30 and put the trailings in the leading and viceversa, they're all the same heat range. could this cause a problem? I will eventually replace them but need the car at the moment...

 

Proper torquing can make a big difference in a plugs heat range/durability. I torque all my plugs after learning this lesson. I feel we should start a thread on spark plug gap, but it's going to really vary from ignition combinations, specific plugs, and fuel.

 

its normal for the leadings to be more worn / have a richer burn than the trailings. However plugs from the front and rear housing should look similar.

And yes its not a bad idea to use a torque wrench on the plugs (if you can fit one...)

 

The ignition polarity of the rear leading is why it often appears to wear more than the front.

Extra wear on the leadings is because they fire twice as often as the tailing plugs. The leading plugs also wear differently front to rear because they are fired with opposite polarities. Wear on the leadings can be mitigated by periodically swapping the plug wires (front to rear) to reverse polarity and extend the useful life of the electrodes. This is possible because the leading plugs are in series on one coil in an arrangement known as lost spark ignition.

Do not attempt to swap or reverse the trailing plug wires.

 

the rear rotors run leaner and hotter due to the design of the LIM. if you have a PFC, add additional lag time to your rear injectors using the commander or datalogit

 

i have 1300 secondaries set at 0.10 front 0.20 rear lag