MS6 Spark Plugs & Spark Plug Gap

neoshade

Member
Hi All. My First Post! :D

After searching the forums for information on spark plugs quite a bit, I've boiled it down to three plugs that work, and several that are commonly recommended and should be avoided.

The available plugs for the Mazdaspeed 6 are:

Plug_____________ Factory Gap (in) ____ Price ea ___ Hot/Cold ____ part #


Stock OEM:
NGK Laser iridium ______ .032 ___________ ~$14 _______ 0 _______ ILTR6A-8G

Denso Iridium _________ .031 __________ ~$10 _______ -1 _______ ITV22
Denso Iridium _________ .031 ___________ ~$10 ______ -2 _______ ITV24


Anything else is Gapped Incorrectly. Adjust at your own risk

- Available on the Internet -
Denso Iridium _________ .044 ___________ ~$10 _______ 0 _______ ITV20
NGK iridium IX _________ .044 ___________ ~$14 ______ -1 _______ LTR7IX-11
NGK Laser iridium ______ .052 ____________ ~$12 _______ 0 _______ ILTR6A-13G

- Prescribed by your Local Parts Store. Don't let them sell you this junk -
Autolite Dbl Platinum __ .051 ___________ ~$6 _________ 0 _______ APP5364
Autolite XP Iridium ___ .051 ____________ ~$7 _________ 0 _______ XP5364
Pulstar Pulse __________ .025 _________ ~$25 ________ 0 ________ EF-1



What I Know:

- 1 step colder per 100 HP increase is a good rule of thumb, and is only recommended for those who drive hard and have increased the Horsepower/Boost
- A colder plug should be gapped smaller to about.28 to avoid knocking
- The Manual recommends a gap of .28-.31

- Gap should never be adjusted with a coin style tool, to avoid breaking the delicate tip.
- Tolerances for adjusting gap are only about .008 each way.
- The NGK LTR7IX-11 and Denso ITV20 are gapped at 0.44, close enough to adjust to .35, but this is almost 2x the recommended max adjustment distance, and may or may not work. This is because of stress tolerances in the metal and more importantly, the angle created when bending the tip. The anode (ground electrode) should be parallel to the tip to ensure even sparking around the perimeter of the tip directly upward. If you want to go colder, get a Denso that is already properly gapped.
- The plugs (autolite, etc) available at all three local auto supply stores are gapped to .050-.054 in. Don't even think about it.


UPDATES
So, I've since learned that the factory plug is NGK ILTR6A-8G, .032 gap
Also, NGK has some excellent documentation on their plugs. They have charts showing application for every vehicle, comparing other brands to their equivalent, and their naming convention. Just search for it.
The part number indicates the type of plug, temperature, thread size, and gap.

NGK Part naming chart
http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf
 
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Regular parts store is more for older and non-boosted cars. I ordered mine for my non-turbo 2.3 6 and NGK had exactly what I needed. E-mail them what you need and you'll get a great response and suggestion.
 
Denso ITV22's are one step colder than stock, while the ITV24's are two steps colder. I don't know the heat ranges off hand, but you should be able to find them from the website.

For the MS6, it's widely recommended that you avoid the NGKs and go with the Densos, so that you can properly gap them without exceeding their tolerances. They are the same price at most places, so choose wisely.
 
stock ones should be NGK Laser Iridiums... which is the ILTR6A-8G, an 8mm pre-gapped plug... the motor was spec'd and designed with the metric system, so you will be fine putting in the plugs as-is... it is not necessary to regap them slightly smaller using the archaic imperial system

these plugs should last at least 60k miles anyway, no need to mess with them!
 
Those gaps are still a bit much. Many techs recommend .024-.028. I had problems with too much gap and actually blowing the spark out causing a P0300 CEL for multi-cylider miss-fire. I gapped the plugs to .025 and solved that problem. Going one step colder is recommended if you are using COBB AP programming.
 
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I have the ITV22's in my car (stock) and they work great. I didn't adjust the gap what so ever. I swapped them out because when I first had the far the stock plugs were fouled and I would misfire in 5th and 6th on the highway....ITV22's solved that in a hurry, though.
 
So Lucas, you're running the ITV22's completely stock and everything is smooth? I'm planning to do plugs this summer, and I'm pretty close to stock. Probably will end up with SRI, TIP, and possibly a test pipe in the near future for power mods.
 
So Lucas, you're running the ITV22's completely stock and everything is smooth? I'm planning to do plugs this summer, and I'm pretty close to stock. Probably will end up with SRI, TIP, and possibly a test pipe in the near future for power mods.

When my car was stock I ran ITV22's and it made the car run smoother.
 
So Lucas, you're running the ITV22's completely stock and everything is smooth? I'm planning to do plugs this summer, and I'm pretty close to stock. Probably will end up with SRI, TIP, and possibly a test pipe in the near future for power mods.

Yep, completely stock and the car runs much smoother than it did before (fyi, stock plugs w/ 30K miles). I'll be adding the same things that you are....Cobb SRI/TIP ordered and the test pipe is waiting to be installed. I'll let you know how everything works out once it's all in.
 
Chris, how are the ITV24's treating you? I've been seeing more knock again, so I'm thinking of going to a 2 step colder plug to try and counter it.
 
Chris, how are the ITV24's treating you? I've been seeing more knock again, so I'm thinking of going to a 2 step colder plug to try and counter it.

Running 93 octane with 10% ethanol (actually 94.5 octane) on the Stage 2 +TMIC map I'm still seeing a .3 or .7 here and there at partial throttle. Aside from that, I'm not getting the 2's and 3's of KR I was getting with one step colder. It has been a very good experience thus far. I don't think I would go any farther than 2 steps colder though.
 
2006 Mazdaspeed6: SPARK PLUG

Alright,

So ive been thinking about which spark plugs i should be putting on my ms6 and not too sure which route to go..

I was looking at the NGKr's and the DENSO one step colder. I live in Houston, TX so its fkn hot. idk if that matters or not..

if anyone could be of any assisstance, I would greatly appreciate it.

Thanks,
pakman
 
The performance difference between the two brands is negligible. I would only go with one step colder plugs if you have some performance modifications done to the car. Like an intake, full exhaust, intercooler, and more boost then stock or if you are having problems with detonation. Without the added heat from the extra horsepower the colder plugs will just foul out faster.
 
Hey RJ,

I couldn't view the second link from where I am. I did check out the first link. I've seen that kind of stuff before. It's a gimmick. From the outside, one could see "wow, that's a pretty neat idea".

The energies behind what they call an "ultrasonic harmonic" are actually lower than the energies provided by the spark coming from the electrode. There will be some energy loss on the part of the spark by way of resistance as it passes through the molecules that make up the air/fuel mixture. The energy loss experienced by the "ultrasonic harmonic" is much greater than the spark as it attempts to condition each molecule instead of passing through it. However, even with that energy loss the air/fuel mixture will still be far more conducive to electric current than a differential pressure. In the end, the spark will still do all the work.

It's a shame that people don't have to prove their idea works to get a patent. It's misleading to the consumer. I guess congrats to them for coming up with something that they can piggyback on Panasonic's marketing efforts. I hope they've made enough to pay for the patent.

Stick with Denso Iridiums for your turbo car.
 
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possible correction

Everywhere I look, the Denso ITV20 (stock compatible plug) is not gapped properly and has a .044 gap, which is out of the range of what is recommended for the Mazdaspeed.
 
If you're going to stay with the stock heat range plug, then just got OEM and get the Mazda NGKs. It's a bit of an odd system, but it sounds like colder than stock should be Densos, and stock should be OEM (NGK).
 
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