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**CORRECT** MSP spark plug list

I decided to post a new thread about the proper MSP spark plugs because there have been many threads about this over the years and there's too much conflicting information. Some people got the correct spark plugs, while many others didn't. You really can thank Mazda for this because they screwed up the information in all sorts of MSP related documentation that somehow made it past the editors to the printing presses. Should any of you be surprised that they screwed up the spark plug gap spec in the shop manual too? Many of you already have been using the plug specs information from the Owner's Manual Addendum which is actually correct despite it being printed months before the shop manual was!

Due to these discrepancies, it's no surprise that aftermarket parts catalogs everywhere have it all wrong. Even NGK, the original spark plug supplier for the MSP screwed up their listings! Auto parts stores use the information published by these aftermarket parts makers and therefore when you buy spark plugs from a parts store, you usually get the correct plug but wrong gap! That's right, correct plug, wrong gap. Spark plug makers actually make spark plugs that are pregapped from the factory to speed up installation and make life easier. When MSP owners or repair shops buy spark plugs from the parts store, they typically get the wrong gapped plugs and some fail to notice this by assuming they're the correct gap and just install them without giving them a second thought. Initially, this won't cause any problems as a non-turbo Protege was designed to run the larger 1.1mm (.042") gap. But in a MSP, due to boost pressures and additional heat, this causes the ignition coils to work harder and wear out prematurely since greater spark voltage is required to ignite a spark plug in turbo engine. It has been common practice to reduce the spark plug gap for a turbo or supercharged engine to prevent "spark blow out" and reduce the strain on the ignition coils.

What's wrong with regapping spark plugs? It wastes time, you risk damaging the electrodes of the fine tipped platinum or iridium plugs. In fact, NGK and Denso do not recommend regapping iridium plugs because of this. Many of us have done this in the past but it is a great inconvenience. That is just one issue, but the most important reason why it is a bad idea is you can cause the ground electrode to go off center, causing diminished performance, reliability, and longevity. Why risk it?

This is a list of Mazda approved spark plug brands. All are pregapped to the correct 0.8mm (.032").
Tightening torque spec: 10-14Nm or 1.0-1.4kgfm or 7.4-10.3ft lbs (less than non-turbo Protege). DO NOT use anti-seize!!!

Stock replacement (dual platinum), 100% Mazda approved, Good for at least 30000 miles:
NGK PZFR6F (stock # 6876, Mazda # 0000-18-KJ11)
Denso PKJ20CR8 (stock # 3173, NLA from Mazda)
Champion RC8PMPA (NLA from Mazda)
Those 3 spark plugs listed are listed under the 2002 Millenia supercharged. The list is accurate as opposed to the 2003 Protege one.
Single platinum plugs such as the NGK G-Power are not listed because they are lesser than stock and do not last long with the MSP's waste spark system since the ground electrode is just a conventional nickel alloy

Long life iridium replacement (iridium tipped, platinum ground electrode), stock heat range, Good for at least 75000 miles:
Denso SKJ20CR-A8 (stock # 3371)
There is no NGK equivalent as their iridium plugs that work in our cars are pregapped to 1.1mm (.042")
Iridium only plugs such as the Denso Iridium Power is not listed because they do not last long with the MSP's waste spark system since the ground electrode is just a conventional nickel alloy

Colder type, nickel "copper" alloy only. Not necessary below at least 20psi or street applications! Good only for 10000 miles
NGK ZFR7F (stock # 5913)
Denso KJ22CR-L8 (stock # 3296)
No iridium or platinum versions available.

One other thing I noticed here is too many people switched to running colder plugs without a legitimate reason. They did it because they turned up the boost or their car is "faster". Those are no legitimate reasons at all. there is ZERO performance benefit running colder plugs on a MSP with bolt ons. In fact, performance maybe worse with these colder plugs because they can foul easier. The only reason to run colder plugs is if you are experiencing preignition issues. This can sound like pinging. You can "read" a spark plug to see if it's running too hot or not. Many of you don't need this. Go take out your stock heat range plug and "read" them. Trust me, many of you are fine with the stock heat range, especially if you upgraded your cooling system, such as installing a colder thermostat. Another thing I noticed is, many of you are running the BKR7E-11 colder plug, this is the wrong reach plug for the MSP. It was designed for the non-turbo FS-DE and BP engines. This short reach plug will fail to produce a complete combustion and will take away the low speed smoothness that the long reach ZFR7F can offer.

I did not list any of the stock heat range "copper" plugs here because they don't exist in the correct gap. Run them if you like under the belief that they're "better", but they're not because of the larger quench area, shorter duration spark, and faster wear, causing inconsistent performance over time. Mazda specified platinum plugs in the MSP and iridium plugs in the MSM for a reason. It is so that they will last the 30k miles reliably until a major scheduled service is due but more importantly, so that they can maintain the performance characteristics of the engine throughout those miles and to ensure their emissions do not increase also. They are also meant to ensure coil pack reliability (excessive plug wear or bad wires kills coils). As a matter of fact, when I first installed my turbo, I had 5000 miles on a set of "copper" ZFR6F-11 spark plugs. I did not regap them but the engine ran fine. 15000 miles later when I got a free set of used NGK Iridium IX plugs (I don't run these any more, I now run regapped IZFR6F-11 but will use SKJ20CR-A8 in the future) from a friend, I swapped them out and saw how quickly the "copper" plugs were worn. They looked the equivalent of 50k miles wear on a non-turbo engine. Some of you don't mind changing spark plugs every oil change or every other oil change, but it is environmentally wasteful, financially wasteful, waste of time, with zero performance benefits (for those running stock heat range). These are just my opinions based on scientific data and facts. I'm not a spark plug salesman and I'm not trying to sell any of you the latest and greatest unobtainium spark plug. A properly gapped double platinum or iridium/platinum spark plug will give you trouble free miles and consistent performance for at least 30k miles due to the fact that they can tolerate high heat better and do not wear quickly under these high pressure, high heat conditions "copper" plugs do. Spark plugs behave much differently in a turbo engine due to the additional cylinder pressures and heat. Regular "copper" spark plugs have such a soft material that they wear quickly under these conditions without any performance benefit over a double platinum or iridium/platinum spark plug. A double platinum or iridium/platinum spark plug provides a smaller quench area, longer and hotter spark, and reduced wear which is what allows better flame propagation, therefore more complete burn for this consistent performance as well as cleaner emissions to happen. On a non-turbo engine, there's really no difference in any spark plug you install, but things are much different in a turbo engine due to the combustion chamber pressures and temperature differences. Platinum or iridium spark plugs might not add power, but they sure will give you the consistent performance and smoothness we all demand. Your choice, but think first before you go "fix" what isn't broken!
 
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Viralphrame

electric heart strike
Am I correct in assuming that the Denso SKJ20CR-A8 plugs come with the correct gap for the MSP from the factory?
 
all plugs listed are the correct pregap... the last digit of a NGK or Denso part number is the gap size in millimeters, but the NGK numbers listed do not have the suffix numbers and are the "default" 0.8mm gap, if you get a NGK plug with "-11", it is 1.1mm gap, a different stock number, and shouldn't be used in the MSP unless regapped
I will not list plugs that are the wrong gap, plenty of information of those found elsewhere and bad parts catalogs/manuals
 
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Viralphrame

electric heart strike
all plugs listed are the correct pregap
I will not list plugs that are the wrong gap, plenty of information of those found elsewhere and bad parts catalogs/manuals
I apparently skimmed over the part where you stated that "all are pregapped to the correct 0.8mm." My bad. Thanks for the helpful info as always, Edwin.
 
:
2003.5 Mazdaspeed Protege
whould this Denso Iridium Power Spark Plugs ITV22

spark plug work for this car they have the right gap just thinking about buying them
what you think are they going to work ?

thank you
 
:
2003.5 Mazdaspeed Protege #1827
Still can't find any spark plugs that aren't already gapped at my local AutoZone and oreillys. Unless I've been looking at the wrong ones. Help?

Edit: So I bought the NGK 3271 spark plugs at AutoZone for $13 and some change. And I just tapped the bottom of the spark plug until it was able to be at a .028-.032 gap. Just installed them. Haven't drove around yet. My old spark plugs were at .046-.050. Huge! Will update again in a bit.

Edit: So far so good. Drives way better then before. I'm guessing this would be a quick fix for anybody who is waiting to get plugs you don't have to do this method. Hope this helps!
 
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ZealoustheEnder

Contributor
:
2003 MazdaSpeed Protege
Fantastic! I just finished a forged build with head work, intake, exhaust and manifold. And I think my problem is the spark plugs.
I had to send my buddy to the auto parts store to get plugs because I was missing a plug out of the set of four in good condition. While he came back with so dual fire pregaped plugs because they could not match my original. I will get the right plugs in ASAP thank "TheMan"
 
It seems this thread no longer is stickied as are many of the other old useful threads...
A LOT of newbies are spreading misinformation and doing bad things to their cars again

But for those reading this 3 years later, ignore what these people suggested:
whould this Denso Iridium Power Spark Plugs ITV22

spark plug work for this car they have the right gap just thinking about buying them
what you think are they going to work ?

thank you
The ITV series plugs are too long, you're going to smash up your pistons if your engine even gets to run!

Many thanks for this post! I will be replacing plugs soon. What do you think of the Denso IK20TT plugs (part # 4702)?
It has the wrong gap and wrong reach... run them on a regular Protege, but not a turbo one!

Still can't find any spark plugs that aren't already gapped at my local AutoZone and oreillys. Unless I've been looking at the wrong ones. Help?

Edit: So I bought the NGK 3271 spark plugs at AutoZone for $13 and some change. And I just tapped the bottom of the spark plug until it was able to be at a .028-.032 gap. Just installed them. Haven't drove around yet. My old spark plugs were at .046-.050. Huge! Will update again in a bit.

Edit: So far so good. Drives way better then before. I'm guessing this would be a quick fix for anybody who is waiting to get plugs you don't have to do this method. Hope this helps!
This guy bought the wrong plugs without paying attention to the information provided in this thread... the plugs he got are gapped wrong, but at least they will equal factory specs once regapped
Denso IK22 is colder plug. From my research they fit correct. But who knows that was 7 years ago.
They are one step colder than stock and the gap is correct, but the reach is wrong... it'll work OK but not optimally because of this and also because they are only iridium with a nickel alloy ground electrode... they don't work as well on a waste spark system and wear much faster

I don't see a reason why anyone want to use the standard reach (what regular proteges use) plugs, but if you do, you might as well go for Denso's VK20Y (stock # 3720 single pack or 3950 twin pack) or VK22 (stock # 0730 single pack or 3730 twin pack)... these are fine Iridium tipped with a platinum ground electrode and are gapped correctly... VK20Y being stock heat range, and VK22 one step colder... BUT THEY ARE STANDARD REACH... The NGK equivalents are BKR6EIX-P (stock # 3099) and BKR7EIX-P (stock # 2690)... stock heat range and one step colder, respectively, and gapped correctly... BUT WHY?
 
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