Let's Talk Spark Plugs

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I know what you're thinking, "Another spark plug thread? Really?" :doh: Yes, really. Everyday we seem to receive inquiries from customers regarding which spark plugs he/she should run in their 1.5L Turbo Honda. As these cars become more commonly modified these questions are going to continue roll in.

Let's start with the basics. Honda provides a nifty little maintenance schedule minder for those with stock/near-stock cars that drive rather "normal" with very limited spirited driving. Maintenance Minder 4 (100,000 miles) is the factory recommended interval those covered under the "normal" driving category. However, it is not a bad idea to check the plugs a bit more often than this if tuned, moderately modified or if you enjoy racing around town all the time like Johnny Tran all the time.
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The Honda factory spark plugs for the 1.5T Civic Non-Si are NGK 95112 Laser Iridium Spark Plug ILZKAR8H8S Heat Range 8 and NGK 95660 ILZKAR8J8SY Laser Iridium Spark Plug for the 1.5T Accord, Civic Si, CR-V, 2.0T Accord and RDX. The only differences between these two plugs are the gaps.
*Technically the 1.5T & 2.0T Honda Accord 2.0T and Acura RDX use a DILKAR8P8SY Heat Range 8 Honda part number 12290-6A0-A01, which is a Japanese NGK spark plug and can only be purchased through Honda at this time. However, it has identical specs of the NGK 95660 ILZKAR8J8SY plug and can be interchanged.

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NGK Laser Iridium Spark Plugs provide superior ignitability and long service life.

The fine wire center electrode and the fine wire ground electrode offer the smallest tip diameter available with Iridium and Platinum surfaces that ensure a slow wear rate, provide a stable idle, offer superior anti fouling, improve your fuel efficiency, and lower your vehicle's emissions.

Features
  • Laser welded Iridium center electrode tip
  • Platinum disc welded to backside of ground electrode provides
  • “Trivalent Metal Plating” provides superior anti-corrosion and anti-seizing properties
  • Faster starts and quicker acceleration
  • Long service life, better fuel economy and lower emissions
  • Best OEM Iridium spark plug available
  • Original Equipment Manufacturer approved design
These plugs are supposed to come out of the box with a 0.030" gap (NGK 95112) or 0.032" gap (NGK 95660), which is within factory spec for these cars. However, we always recommend checking the gaps just to make sure.

1.5T Si Factory Recommended Electrode Gap:
Standard (New)
0.70-0.75 mm (0.0276-0.0295")

1.5T Non-Si Factory Recommended Electrode Gap:
Standard (New)
0.7-0.8 mm (0.028-0.031")

K20C1 Factory Recommended Electrode Gap:
Standard (New)
0.7-0.8 mm (0.028-0.031")

Torque Specs: Aluminum: 10.8-14.5 lb. ft.

Longevity: 100k Miles

"But what if I'm full bolt-on or Stage 5 broooo?" At this point in time we recommend stock plugs for ANY power goals you may have. We are currently running stock plugs gapped down to 0.018" on our shop car making well over 600 horsepower without any issues whatsoever. If you're moderately to extremely modified and/or running high boost levels you will most likely need to gap your plugs down. Higher cylinder pressure(s) will increase the difficulty for spark to jump from the electrode to the strap. Tightening the gap between the electrode and strap will allow spark to jump much easier with higher cylinder pressure(s), reducing the risk of ignition misfire. If professional tuned/tuning, we recommend discussing spark plug gap with the tuner.

For reference, we have been using/recommending stock spark plugs in high power 8th Gen, 9th Gen and now 10th Gen Honda Civics for years without any ignition related issues. Modern coil on plug (COP) ignitions systems have replaced outdated distributor based ignition systems allowing, factory ignition systems to work much more efficiently.

Please do not fall for "1-step colder" plugs, "similar" plugs your buddy recommended, brands other than NGK or knock-off NGK plugs. At this point in time there are no "colder" spark plugs available or "similar" plugs that will work. We have worked directly with NGK to test fit a few different plugs that we were told may work. They did NOT. There's a reason Honda uses NGK. There are quite a few people offering fake/knock-off NGK plugs (CLICK THIS LINK ON HOW TO SPOT AUTHENTIC NGK SPARK PLUGS), so be sure to purchase off of a reputable vendor. (cough cough, we sell these) :thumbsup:

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jbuttke1179

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What about the SI? The plug for that shows as a 95660 with the only difference being the plug gap (.30 vs .32 for the 95112). Any idea why Honda specs out a separate number?
 

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What about using SI plugs in non-si engines or viceversa?
 
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What about the SI? The plug for that shows as a 95660 with the only difference being the plug gap (.30 vs .32 for the 95112). Any idea why Honda specs out a separate number?
The only difference between these two part numbers is the gap. We spoke with NGK about this and they too laughed at the idea of two different part numbers. :dunno:

What about using SI plugs in non-si engines or viceversa?
Using non si plugs in an si would cause misfire and a lean condition, happened to me before lol
0.002" should not have caused a misfire unless you were running very high boost or if something else was off. NGK even recommends checking the plugs to ensure that the gaps are correct, as do we. It is possible that the gap(s) were incorrect out of the box. These plugs can be used interchangeable, so long as they are gapped to spec.
 

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The only difference between these two part numbers is the gap. We spoke with NGK about this and they too laughed at the idea of two different part numbers. :dunno:




0.002" should not have caused a misfire unless you were running very high boost or if something else was off. NGK even recommends checking the plugs to ensure that the gaps are correct, as do we. It is possible that the gap(s) were incorrect out of the box. These plugs can be used interchangeable, so long as they are gapped to spec.
Yea I only had misfire once I got over 17psi or so. And yea they should definitely be checked even if ordering the correct ones, my reliable shop and Honda both installed incorrectly gapped plugs. Honda had found the first incorrect ones and then it turned out the ones they used also ended up being incorrect out of the box
 

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Is there a certain psi range at which you'd recommend gapping down the plugs? Would gapping down the plugs be beneficial at all regardless? I like the sounds of reducing the possibility of misfire and I'm at around 22.5psi, non-Si.
 
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WOPSiWOT

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What kind of change interval would you recommend/are people running? Assuming you want to be proactive about it. Obviously lots of factors at play, specifically modifications/tuning. What about on a "Stage 1" tune (TSP Stage 1), since that is pretty common? 30k?
 
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Is there a certain psi range at which you'd recommend gapping down the plugs? Would gapping down the plugs be beneficial at all regardless? I like the sounds of reducing the possibility of misfire and I'm at around 22.5psi, non-Si.
^You can find quite a bit of useful information here. 22-23 PSI is starting to get a bit up there in boost, so tightening up the gap a bit (to around 0.026 - 0.028") is probably not a bad idea.

What kind of change interval would you recommend/are people running? Assuming you want to be proactive about it. Obviously lots of factors at play, specifically modifications/tuning. What about on a "Stage 1" tune (TSP Stage 1), since that is pretty common? 30k?
It's not a bad idea to check plugs every other oil change after 30K. However, given the fact these plugs are rated to 100K, this is all just for peace of mind. Typically the plugs will last you until the maintenance minder light unless the engine is majorly abused or if something freakishly goes wrong.
 

r.camlin

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^You can find quite a bit of useful information here. 22-23 PSI is starting to get a bit up there in boost, so tightening up the gap a bit (to around 0.026 - 0.028") is probably not a bad idea.
Thank you for that. Just ordered four plugs lol.

I noticed that they're 12mm thread (which doesn't tell me much lol). Do you happen to know if it's a standard M12 thread pitch (1.75)?
 

calvin13386

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Is the ngk rx premium plug(LKAR8ARX-PS, 94207) suitable for 1.5T no si?

If suitable is it better than laser iridium or what the pros and cons?
 

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We only have the non si version here and we also have the plug model you mentioned.

But I'm just curious whether are there better plugs out there as compared to the stock. I found these rx premium plug over the stock plug which claims to be suitable as advertised and claims to be better than stock
 
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Thank you for that. Just ordered four plugs lol.

I noticed that they're 12mm thread (which doesn't tell me much lol). Do you happen to know if it's a standard M12 thread pitch (1.75)?
Awesome! Spark plugs are fine thread, so the thread pitch would be M12x1.25mm.

Is the ngk rx premium plug(LKAR8ARX-PS, 94207) suitable for 1.5T no si?

If suitable is it better than laser iridium or what the pros and cons?
We're not quite sure what this part number is, but at this time there are no other suitable/recommended plugs for these cars.

We only have the non si version here and we also have the plug model you mentioned.

But I'm just curious whether are there better plugs out there as compared to the stock. I found these rx premium plug over the stock plug which claims to be suitable as advertised and claims to be better than stock
Again, there is no other suitable/recommended plugs for these cars. There is no need for a "better" or "upgraded" plug. We talked and worked directly with an NGK rep whom was in our shop and sent us numerous plugs to try. We had high hopes for their Ruthenium HX plugs, which are supposed to be their "better" plug. However, upon testing, we discovered that the factory coil boot does not fit over top insulator of the plug (white body) because the Ruthenium top insulator is too fat. This was news to NGK. Unless this has been fixed over the past few weeks (which we doubt it has), there are no other compatible plugs available.

Ruthenium Information
 

kshawn

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I'm still amazed my ngk plugs haven't needed to be gapped down yet. 30psi+ running meth injection. About to add e30-40 to the mix so I'll probably need to now. But even when running E35ish @ 28psi, no meth injection, I wasn't missfiring yet.

Maybe I'm just getting lucky :rofl:
 

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1.5 cvt Hondata +6 injen cai rv6 catless.
NGK 95112
I was getting real bad mpg (36 max) and sputtering from 3000-4000 while gapped at .032”
I gapped them down to .028” and it’s very smooth response and back to 42-43mpg

Shout out to Oreilys for the .17 cent Champion spark plug gap tool(s)

And big thanks to PRL for this thread. I had actually thought stock gap was .028” until checking NGK website and seeing it .032” . I might actually go down to .025-.027 since running Hondata +6. The real noticeable difference comes when you run the catless pipe. A lot more room to breathe now.
 
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