Wheelhaus

iTrader: (2)

So apparently the BPR7ES plugs from NGK won't work, and if it's the standard size plug for an 8, then it will not properly fit a 9 because of the MIVEC head..

They're too short and the threaded end, and tool long at the ceramic end. The coil packs sit 1/4" too high and can't be bolted down.

Plugs that are known to fit our beloved IX's:

NGK ILFR7H (OEM) Iridium
http://www.sparkplugs.com/more_info.asp?AAIA=&pid=20451

NGK LFR7AIX Iridium
http://www.sparkplugs.com/more_info.asp?AAIA=&pid=16602


What a pisser. Here's a pic highlighting the seating point as this controls how deep it goes. Boo hiss.

High_PSI

iTrader: (50)

Interesting and subscribing.

EvoVIII_MR2005

iTrader: (2)

This topic has been covered several times on the boards...Only HKS has sparkplugs out for the 9.

Evo_Jay

iTrader: (17)

+1

Fourdoor

iTrader: (11)

A link for the EVO IX guys to that thread, or a link directly to the HKS plugs would be appreciated. We are trying to be a friendly community here and help each other right?

Keith

housedj

iTrader: (2)

yup the IX plugs are 7mm longer than the VIII's due to the taller head. they needed space for MIVEC & to eliminate "lifter tick"...

cbrtrx

subaru sti plugs in ONE heat range colder work well in the 9, they run better then my stock plugs did and are taking the higher boost just fine, they retail for $8 each

Wheelhaus

iTrader: (2)

Yes. I had searched for days and found nothing more conclusive than "HKS is the only company that makes plugs for the 9 and they're over $100 for the set". First, I don't like HKS, Second, I'm not spending $100, and Third HKS is NOT the only company to make plugs for the IX, as the plugs I pulled out were NGK.

So this is as difinitive as I could prove it, because yes, it's been discussed many times before, but nothing was really 100% believable proof (from what I found) because there's so much muck and garbage to sift through on this board.

edit-
BTW HKS's site says nothing about plugs for the IX. If theire generic applications do match, I'm still not paying $21 per piece.

Evo_Jay

iTrader: (17)

You might be able to go to a Auto parts store and have them cross refrence what plugs work on the IX.

Wheelhaus

iTrader: (2)

^ Yes. If anyone does this before me please post brands and model numbers and I will edit them into the original post.

cbrtrx

i guess you missed my post , ngk lfr7aix , retail for $8 each and handle the high boost better then the stock ones

Wheelhaus

iTrader: (2)

no I didn't miss it, you only said Subaru STi plugs will work, and that could vary per year and per EDM JDM and USDM models through the years... Thanks for clarifying though, it's been added.

SuperHatch

iTrader: (23)

Where is the documented source you heard this from? I.E. - Mitsubishi Engineering Documents. Because until you do, this is completely conjecture, and very poor at that.

The only benefit I see of a taller surface between the top of the combustion chamber and the base of the spark plug valley is more room for cooling passages, which makes much more sense than an effort to eliminate "lifter tick".

Wheelhaus

iTrader: (2)

It makes sense. on Sparkplugs.com it notes the BPR7ES (well known plug to work with the 8) has a 3/4" reach. That translates to 19.05mm depth. The ILFR7H (OEM plug on the IX) has a reach of 26.5mm depth. that's 7.45mm increase. Magazine articles even mention that the spark plugs are different. It's most likely due to the MIVEC head, it makes perfect sense. But I KNOW first hand that a plug that is known to fit the VIII perfectly.. will not fit properly in the IX.

edit- nevermind, you were responding to why they're taller, not if they actually are.

Evo_Jay

iTrader: (17)

Last night, at like 3AM I typed this exact responds, but deside not to make DJ look bad for the 12,836 time.