Does anybody know which spark plugs I should get to replace my stock plugs? I have a Garrett GTX2863R .63 AR turbocharger, and am working on perfecting things, and have been told to get one-step cooler plugs. Are my stock plugs Denso brand, and should I stick with Denso, or go with one of the NGK products that are spec'd for my product, e.g.:

NGK 5018 LFR5AGP Single Platinum
NGK 4469 LFR5AIX-11 Single Iridium
NGK 96779 ILFR5T11 Iridium/Platinum

Naturally I would get one-step cooler, which I think changes the 5's in all the second column part # to 6, e.g. LFR6AGP, etc.

Also, I've heard from someone that my gap should be smaller than stock, around .0028-.003. But the plugs all come with a gap of .0044, if I remember right. One shouldn't adjust gap on an iridium spark plug tip, I hear, so I don't know how to proceed. Should I avoid iridium plugs, so that I can safely regap, or can I regap iridium plugs just fine, or should I be satisfied with the stock gap because it won't make much/any difference anyway to "optimize" the gap anyway?

I'm clueless. Help? :-)

Eternally grateful if you can spare some wisdom, folks.

Sincerely,

-John

 

I dont know but i would also like to know! so bump!

 

I know when Dezod was building my kit, i inquired about this exact question and was told it was not necessary. Don't remember the logic/reasoning behind it. When i did my turbo research though, most of the places said it was a good thing to do so i wanted it done. Hopefully Paul_Dezod can enlighten us on this topic.

 

i replaced my stock denso's this past week and they were iridiums and well i replaced them with the NGK irdiums without gapping them, just what they came from the factory and honestly the car is running a lot smoother, idol is like night and day and the only mod i have is a weapon r intake

 

This is a turbo application so the person who commented on swapping their plugs to the NGK's won't apply to us.
I went with 1 step colder Denso's. And I gapped them to .0024. Seemed to work well for me.

Delorean2006, your car is running better cause your plugs were probably just old and needed replacing anyway.

 

^Dude, you're still around?! Glad to see you back. You're knowledge was missed.

 

Life got the better of me for a while there. Still have the tC2, but no longer at Wellesley Scion. I was laid off as they no longer needed a business manager(they are making the sales managers do my old job). Plus I moved and finalized my divorce.
Either way, yes I'm still here

 

Sorry you went through all that. Glad to know you're still around.

 

For low boost, less than 10 PSI, you can run stock plugs just fine. None of these cars have that much mileage or abuse on them where it would warrant a mandatory change in plugs.

Typically, I like to change to one step colder at 10 PSI or more just to help keep that plug cool as possible. Too cold of a plug range can make tuning awkward and not help combust the entire mixture. Too hot of a plug can cause pre-ignition detonation. So it's a balancing act.