MRomano

i was wondering if anyone can tell me why the trailing and leading spark plugs are differnt....i was trying to explain to someone why and i couldnt tell them...just wondering if someone could clarify and maybe give the reaso they are different...and yes i know how the rotary motor works...just kinda curious

luizajeff

Heat as I understand. The trailing needs the 9's because of the heat but so many just put trailing plugs in all four I don't think it really matters after that.

MRomano

so its just a heat issue then.....i just changed mine and when i was lookin at the plugs there was 1 trailing and the rest were leading how messed up is that...whoever had the car before me mussta been smokin somethin...would this have done any damage to the motor of any sort

Sonny

The leading plugs are hotter plugs (7's). Running trailing plugs in all 4 positions is a common performance upgrade for people who beat on their cars a lot. The cooler plug reduces chamber temps some and therefore reduces chances of detonation but is also more prone to fouling.

Sonny