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Discussion Starter · #1 ·
I'm thinking of putting a set of NGK Iridium IX plugs in my WRX. Any thoughts on this? I'm also making the assumption that the plugs will fit - but I'm not sure if spark plugs are all a standard size, or if they vary from car to car... call me naive.


Thanks everyone.


RGE
 

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Automobile spark plugs have two standard sizes.
The big ones are typically for older, large displacement engines or small engines, like in a lawnmower.
Pretty much all cars and motorcycles use the small plugs these days.

I'm thinking of replacing my plugs, too. Anybody know where the hell they are? I'm assuming you have to do it from underneath the car.

-Jim
 

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With a mild setup go with a 7 heat range. Stock is 6. I'll be getting some blitz platinum 7 heat range plugs soon just to try. I doubt they will make much of a difference but you never know. If you are runing 400 HP or something crazy go for an 8 heat range.
 

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from what i understand...

spark plugs are generally designed by companies following a particular type or make of a car. NGK plugs are generally renowned for making plugs that run in higher performance japanese cars.

a higher performance plug or one with a higher temp. rating is designed for cars that run hotter than others. the spark plug acts as heat exchange to remove the unwanted heat from the combustion chambers to the engines cooling system. if it weren'tfor your plugs, there would be no primary regulator of heat levels in the combustion chamber of your engine. so if it is too cold, you'll have fouling (or lack of something to make fire!) -- too hot, and you'll pre-detonate or misfire.

so a higher rating = higher heat dispensing ability. this higher rating plugs have a longer nose (i think this is the "big plugs" you guys were talking about) and a thicker ceramic insulator. i think the center electrode's construction is also a factor here. anyway, god is right, the higher heat rating NGK's are more than fine for the rex. they should also have a pretty long life.

IMO there is no need to go for the split fire and other gimik plugs out there. some have side effects, including severe wallet injury for the relative return.

I am also pretty sure NGK is what SOA reccomends wrx owners use.


DR
 

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Oh!

and platinum, i know there is not cap and rotor on this thing... im so confused by the whole direct ignition... god, do we need to put this thing on a lift to tune it up?


dR
 

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DR, I forgot our cars have coil-on-plug ignition. It's pretty simple really. Instead of having one or two coils in a central location and then running those silly spark plug wires, four coils are mounted directly on the spark plugs. They have regular old twelve volt wires to them and charge and fire the plug right from there. This results in better spark control and less electro-magnetic interference (EMI) because the high voltage current isn't traveling any where close to as far.

God, same question as DR: Do I need to buy a lift to tune up my WRX?

-Jim
 

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Discussion Starter · #8 ·
And the part number is...

For the NG Iridium IX plugs for the 2002 Subaru WRX:

NGK Part #BKR6EIX , or stack #6418

These plugs are simply unavailable in Canada - period. Somebody please correct me if I'm wrong, but this info came direct from NGK Canada.

Thanks all.

RGE
 

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double checked.

my father's cataloging system at his store doesn't have 2002 info yet. I know the number is in the manual though. those look right theough (6418 does anyway, I never remmebered the full number.

dR
 

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to get to the right hand side, u need to remove the battery and winshield wiper fluid resevoir. on the left hand side u need to remove the airbox.

joe
 

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That sucks! I'm a firm believer that the only thing you should have to remove to change the spark plugs should be the spark plug wires (or coils, in the WRX's case) and the spark plugs!

-Jim
 

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How often do you have to maintain these, every 30k miles? That's not so bad afterall as I'm used having spark plugs on top while just removing the plug wires to get to it as well. At least the oil filter is easy to get to, you don't even have to jack up the car.
 

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I'll be doing new plugs at 10,000 just because. Pick em up for nothing from my dad's store anyway. I figure the break in leaves more deposits on the tips, and I want real consitant burning. the smallest variations in spark mean a lot for exhaust output. if one cylander misses half of its ingnition, you are losing 12.5% of your exhaust output per cycle, and therefore, 12.5% of your spool up ability.


its a delicate job maintaining the proper combustion environment. that little bit means a lot.


dR


ps there is no standard size. there is a ton of different shapes and sizes for all sorts of different makes and models. use the above part number.
 

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Has anyone installed the Denso Iridium Spark Plugs? I have seen a few places claiming gains of 6-8 HP, but don't believe it. Have any of you noticed or dynoed a difference.
 

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I have ran into breakage problems with both NGK and Denso Iridium plugs. I ONLY recommend platinun plugs due to my poor experiences with the Iridium plugs. They didn't make any power over a good platinum plug anyway. I'm using 8 heat range Blitz plugs and they're working like a charm.
 

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The install for the spark plug is pretty time consuming, you have to take out the battery and the intake to get to them. I think you might be able to find some directions no vishnuperformance's website becuase their stage 0 came with some NGK plugs.
 

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i've heard that split-fire's and other gimicky plugs are worth their weight in [email protected]

as for denso's, i've seen dyno proven gain on motorcycles. of course, on the smaller engines of bikes the gain is only 1-2hp, which is relatively significant on such a small motor.
 
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