Both of you, 1 step colder, IKH24 densos.... gapped at .024 to .022 closer to the 2nd number though.

 

I was about to order stock replacements and the link to both the IX RS & MR show "OE Gap .032"

http://www.sparkplugs.com/results_app.asp?aaia=1432585

(I'm running catless TBE, Walbro, GM solenoid ~26psi spike...stock everything else)

 

they lied

you can measure your stock gap if you want... its much closer to .024

 

Ordered...

 

I just pulled my plugs and inspected them today at 13K miles. The were the ideal light brown color, however the gap was a little off on each of them. That would be normal since the gap does widen over time. Since the recommended gap is between .020 and .024, I set mine a .022 and put them back in. My car isn't running meth, but I do run it at 22 PSI.

They would be fine at .024 as most people recommend, however I find that gapping them in the middle of the recommended range is usually a good way to go when you consider that the gap will widen over time.

One thing I haven't seen people talking about here is how the gap length effects performance. Here is my take on that issue, so please correct me if I am wrong about anything:

A bigger gap means more electrical resistance, potentially shorter spark durations and a longer-lasting plug...which is why you usually run a larger with gap copper plugs than you do with platinum or iridium. Copper plugs conduct electricity better, so a larger gap with a copper plug has similar resistance as a Platinum/Iridium plug with a smaller gap.

Ideally, and especially with turbo'd cars that rev high, you want a smaller gap which means less resistance and a reduced chance for the spark to "blow out" at high RPM (maximum spark duration). Iridium/Platinum plugs are not as conductive as copper plugs, but they resist the detrimental effects of a smaller gap much better than copper, which is why using them in our cars is preferable. Another thing to consider about gap length is that it can effect your A/F ratio. If the spark doesn't last long enough to ignite the air and fuel in the combustion chamber, it could lead to a rich condition and reduced performance.

 

glad i found this post, i was about to put evo VIII BRP7es into my IX... yikes, but when i compared i noticed the reach difference

 

to what extent should the car be modded before it's beneficial to run colder plugs? also, any drawbacks from running 2-step colder plugs (heat range 9)?

 

NGK's website recommends going 1 step colder for ever 100 HP added over stock, however if you are not experiencing detonation with the stock heat range plugs, you probably don't need to go colder.

Running colder when you do not need to can result in fast plug fouling, since the plug will be too cold to burn off all of the fuel, a buildup will form on the plug in a short period of time. Obviously that would lead to reduced engine performance.

Just pull your plugs now and see what condition they are in. If they have a chipped appearance, like you see small pieces of metal missing from any part of the plug, it is a sign of detonation and you probably need to go 1 step colder.

 

^^ i jus had my car road tuned, running the motec pnp. car has most of the bolt on stuff so i should be getting abt 400ish crank hp. i figured i should go a step colder too but my tuner told me specifically to get the ngk racing heat range 9 plugs and these plugs cost a bomb

 

I'm 333 HP / 333 TQ at the wheels, which works out to 400 and change at the crank, if you assume a 20% drivetrain loss. My car has stock injectors, a custom tune and 22 PSI boost on the stock turbo. I put about 5K miles on my car like this and my stock plugs were in perfect condition when I checked them the other day.

If your tuner is recommending plugs that are 2 steps colder, which is a pretty big change, I'd be curious as to what his reasoning is because I don't think you really need those from what you just said. I have not had any detonation issues with my car as it is now, and when I re-gapped my stock plugs to .022 it just smoothed the revs out across the whole power band.

So unless you're planning to run meth or boost levels over 28 PSI - something that would increase combustion chamber temps substatially - stick with the stock plugs. If your tuner did his job right there is no reason I can think of that you'd need colder plugs for your current stage of mods.

 

Mine is gapped to .026 or .028(can't remember) at the stock heat range. never had a spark blow out.

 

Luckly I found this, thanks!

 

This thread is awesome, just what I was looking for. I have an intake, exhaust, BC at about 23psi and a fuel pump. I just bought a set of plugs from Buschur for my IX.

I'm planning on gapping at .022, does that sound accurate?

 

Yes, .022 is about right for a IX plug with a little more boost.

 

good info, I got 30K on my stockers...time for a swap