Step colder plugs

b e z

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2009 black mica speed 3
Just wondering where most guys buy there Densos from? I looked online at SU, they werent labeled as the ivt22, I believe that is what the step colder ones are, but Im assuming thats the ones. Also wondering if and where you buy them from are they gapped properly. I have no tool to gap the plugs and I have never attempted to gap plugs.
 
I believe the Denso part number is 5340, (the stock heat range part number being 5339) I have them available next day through my store and so do most of the suppliers in my area (Advance, Auto Zone, Pep Boys)... in regards to gapping, I use a wire type gapper to avoid damaging the tip of the electrode, and they are NEVER pre-gapped. If you can't find them let me know, I can ship some your way.
 
^ Good advice on the wire gapper. You want to avoid scraping against the fine wire tip. The iridium coating is very thin.

And as to the Denso plugs, if you can't find them or want to try something different, consider NGK 6510. That is the one step colder NGK in my sig. They will have to be regapped as they come too large. I like NGK for many reasons, only one of which is that Mazda chose them for the OEM plugs too. When you pull your stock plugs you will most probably see a FoMoCo emblem and an NGK part number!

Bez, what mods you running these days? Unless you are AP tuned for stage 2 and/or running a big catless dp/rp or other fully bolted mods or close to it, you do not need to run colder plugs and will probably run worse off with them. The trick is to run the hottest plug you can while avoiding detonation or early erosion of the tip, and to run the coldest plug you can and not foul. Unless you are monitoring and seeing some KR, or unless you are heavily modded and running high boost with a very free flowing exhaust, colder plugs are a waste of money and are likely to foul.
 
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Current mods as of now, test pipe, tip, sri, bov, hypertech. Though bov doesnt make a difference. I know I wouldnt need step colder plugs but like you said MSMS3 I am seeing knock. I have a dash hawk and for about 2 weeks now I have seen as high as 3.xx in kr when accelerating past 3k. I went WOT yesterday and when I glanced at my Dash Hawk I had noticed some sort of knock then as well, not sure the exact number tho.

I have read that you will register some knock from daily driving but as long as it doesnt get too high of a number, and my knock is on a daily basis and only past 3k.
 
^ Give the step colder plugs a try. Might help with KR. Transition to WOT KR may be normal with your mods, but does not sound good to me. I'd want to cure that. I see zero and want it that way. Do you have access to 93 octane where you are? That will help too. Might even want to change where you buy your gas and see if that helps regardless of the octane number they advertise on the pump.
 
I have always filled up with 93 and I only get my gas from Shell gas stations. I want to say this started happening when it was warm so I didnt put too much thought to it but when I saw it on the colder days here recently and when I went WOT I was worried.
 
I have a set of itv22s if you want them, I was going to install them, but ended up trading in my speed 3, pm me if youre interested.
 
I dont know if local part stores sell them, from what Always Forgive says it seems they do, say I will probably stop by one and check prices on them.
 
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