i bought a pack of 4 spark plugs today, and i was wondering if i have to use different spark plugs for the trailing end and leading end? can i use the same spark plugs for both ends?

the title says it all. is it the same part number as the fd?

 

Back to the store you go.

 

leading (lower) Trailing (top) spark plugs are different from each other

 

so the sparks plug are completely different?

 

they dont look very different but i think it has to do with the temps that they operate at... im not completely sure some one might have a better answer for you

 

They're not completely different only the heat ranges are different. You can switch them if you want but the leadings require bur7eq and trailings bur9eq.

 

The stock NGKs are part number BUR7EQ and BUR9EQ. The 7's go in the lower (leading) holes and the 9's go in the upper (trailing) holes. The trailing are colder heat range than the leading.

 

thanks acid i figured it had something to do with the heat range

 

just don't run hotter plugs in (lower #) the leading than the trailing. A lot of people run four trailing plugs on turbo applications (four BUR9EQ).

 

very helpful, this should be sticky.

 

i run (4) BUR9EQ's...

 

Is there an advantage or disadvantage of running all hotter temp or cooler temp plugs?

Or Is the standard stagger better?

Just asking because if need be i will change mine.

 

yeah i would like to know too.

 

as mentioned above, lots of guys run all 9's on moderately modded turbo cars because they run cooler. for info on why running colder plugs is better see here:

https://www.rx7club.com/showthread.p...trailing+plugs

 

Thanks Touch!

I'll keep mine stock for now. Lol...