M35 Plug Replacement

[scotty nm35]

I have been chasing a set of replacement copper plugs to try with the E85 im about to be running, Apparently the iridium plugs can glow causing pre-ignition. I found the STI's are running similar plugs and they had this list on their forum.

LFR6AP-9 OEM nm35 Stagea (Platinum)

IKH22 5345 Denso equiv. (Im running these at the moment.)

STI List:

NGK IFLR6B (Iridium)--Subaru STI OEM Plug

NGK PLFR6-11 (Platinum)

NGK LFR6AIX-11 (Iridium IX)

NGK LFR7AIX-11 (Iridium IX)--"one step colder"

NGK LFR6A-11 (Copper)

Denso IKH20 (Iridium)

Denso IKH22 (Iridium)--"one step colder"

I still havent worked out what heat range I should be going for, colder if there is pre-ignition, hotter if I have cold start problems from what I have read. Any plug experts around?

Edited March 10, 2010 by scotty nm35

[QWK32]

I still havent worked out what heat range I should be going for, colder if there is pre-ignition, hotter if I have cold start problems from what I have read. Any plug experts around?

thats basically it. something else to think about, if your using too cold of a plug they will foul up quickly. the plugs have a kind of "self clean", to help with soot build up on the electrode. this process wont work as good if a plug that is too cold for your application is used.

i have no idea about what is required for E85, have you looked in the FI section, i've seen a few topics come up about E85?

i've only really used NGK plugs, and can help you out with their part numbers. i have a chart i use that i found on the breakdown of the part numbers you may be interested in. its a few post down in this thread LINK

[scotty nm35]

Thanks Josh, I will take that with me on my hunt around tomorrow.

[gptech]

Hi, I know this is an old thread but I wanted put these plugs out there to see if anyone has tried them.

Brisk ER14YS

They use a silver electrode and are rated for 45k kms, and the 14 is the same as a 7 heat range for the NGK plugs or 22 for the Denso's. And they seem to be popular with the EVO IX crowd.

Thanks,

Grant.

[scotty nm35]

I had a lot of issues running the Denso's, to the extent they completely melted in 10,000k's (although I am pushing things hard.) The stainless threads also seize up in the thread easily without some antisieze on them. They are rated to 160,000 but obviously aren't that good for turbo applications.

I am sure anything will run fine as the stock coils throw a fair spark, but I stick to the NGK's these days, LFR7AIX, due to them lasting so much longer. For $15 a plug it just isn't worth changing them any more often than you have to.

The Evo crowd isn't the smartest... I know this well, as I have a 7.

[gptech]

Cool, I did own a 1990 Galant VR4, so the filter is set to high when I read through any of Mitsi forums.

Thanks Scotty for giving me your advice on the plugs, they will be what I'll order.

Grant.