ok i JUST GOT NEW PLUGS AND WHEN I GOT THEM THE GUY A napa TOLD ME THAT i NEEDED A LEAD PLUG AND A TRAIL PLUG. i DON'T HAVE THE NUMBERS OFF THE TOP OG MY HEAD BUT THEY ARE ngk PLUGS. Does anybody know what I am suppose to have. He gave me 2 different plugs. Which one goes on top. I am asking because when I took the old ones out they were the same plugs and now 2 different ones that the guy gave me. HELP!! https://www.nopistons.com/forums/pub...1047683358.gif

There are 7's and 9's .

Use all 9's if you can.

I belive that the 9's are the trailing plugs.

yes normally they are 2 different plugs. Although some people run the same. On the Ngk plugs they are marked L for leading and T for trailing. I cant recall right now how they go in but you can check out www.iluvmyrx7.com and they have the oem repair manual there. Should take 1 minute to find. Sorry man its been a really rough night and im in a daze right now. https://www.nopistons.com/forums/pub...IR#>/bigok.gif

Leading (have a 7 in the part#) go on the bottom, trailing(have a 9 in the #) go on the top

BUR9EQ is a colder plug needs to go into trailing..

BUR7EQ is a hotter plug needs to go into leading..



i would suggest running all 9s non platinum if you are running more than stock boost...

use all 9's https://www.nopistons.com/forums/pub...IR#>/bigok.gif

for a fd run all 9's



good luck, its less confusing with all 9's anyways! https://www.nopistons.com/forums/pub...IR#>/bigok.gif

Why should you run all 9? What is so different about the seven? But you guys are right cuz when I pulled them out both of them are 9!! https://www.nopistons.com/forums/pub...>/rolleyes.gif

9's have a better spark.

the difference between the two plugs is their heat range. the 7 is a HOTTER plug (because it does not have as much insulation around the plug) . this plug will not be able to perform in a hot running engine as well as a colder plug. It will also not be able to transfer as much heat as a colder plug can. The 9 is a colder plug because (you guessed it) it has more insulation. it can run safley in a hotter engine and retains the ability to extract heat and not melt. hope this helps some??





the rotary is a pretty hot engine, so cooler plugs will be welcome.

Thanks for the help guys. You never fail to answer my questions. I am running two brand new 9's and the cars loves them.

has anyoen actually melted a 7 cold plug in a properly running engine? under 15 psi ?

the 7's are more prone to detonation, seeing is how they are a hotter heat range.... bottom line. if you have a highly modded fd, 9's are better insurance......

I ran all 10's and yes they do foul out if you don't drive hard.

Three words: spark plug cleaner https://www.nopistons.com/forums/pub...#>/biggrin.png



Just as an FYI, I once gained 18 rwhp on the dyno simply from swapping 10.5s in for 9s. Went from 310 to 328. I will say that swapping out plugs on the dyno *sucks*! I burned the hell out of my forearm. It was so long ago I really can't remember my mods.

So if i get iridiums, should i get 9s as well????

By Iridium are you talking about the HKS plugs? Be careful---if I remember correctly, Ernie T lost a motor when the damn electrode came off the plug on the dyno and (obviously) lunched his motor. Vosko, can you validate this? My memory ain't what it used to be--damn Jager https://www.nopistons.com/forums/pub...#>/biggrin.png

Damn Rich.. you have all the bad stories... between your bad gas story and now this. I dont know what to put in my car... lol



BTW.. where did you get 10.5's at???





Bret

nothing is wrong with platinums... they just cost more.. and dont last that much longer than regulars. You can also clean the regular plugs a couple times if you really have to. platinums.. forget it. once there coverd.. you pretty much have to get new ones. so if you have the money to burn... go for it.

Yo Bret,



hehe. Yeah, I know. Gotham sells the race plugs, as does RP, KDR, and I'm sure a shitload of other shops. They're around 30 bones each. I've run them in just the leading holes to cut down on costs and been happy with them. For the coming dyno day I'm going to run 10.5s leading and 11s trailing.

now thats some cash.. might have to get some for those special ocations...lol

I don't drive my fd hard, I mean i do but once a week or so. I don't do any track racing or anything like that, just some street. I'm runing all 9's, do you think this is a good idea or should i go back to 7's.



I have dp, catback, hi-flo, Ic, Ecu, intake, etc.

You should be fine with all 9's.