Spark Plug Cross Reference Recimmendation

[MSq5]

I've been running the usually recommended NGK Laser Platinum PFR8S8EG plugs gapped at .024" or .026". This was from stock through my current dual pulley Stage 2 tune.

Stage 2 dual pulley greatly reduces the life of these platinum plugs. Is there an Iridium equivalent that might have longer life? I seem to recall that some tuners are recommending an Iridium plug with dual pulley tunes.

Is it BKR9EIX? That's a step colder- might foul. Maybe BKR8EIX?

[djn876]

I've been running the usually recommended NGK Laser Platinum PFR8S8EG plugs gapped at .024" or .026". This was from stock through my current dual pulley Stage 2 tune.

Stage 2 dual pulley greatly reduces the life of these platinum plugs. Is there an Iridium equivalent that might have longer life? I seem to recall that some tuners are recommending an Iridium plug with dual pulley tunes.

Is it BKR9EIX? That's a step colder- might foul. Maybe BKR8EIX?

I've run the BKR8EIX with no issues for a little while. The stock ones were fine too, and then the Brisk DR12YS which the car seemed to like best, but dont recommend if you wanted more longevity as these will probably need to be replaced even earlier than stock.

Even at DP, I you probably don't need colder plugs on a mild ratio.

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[MSq5]

I've run the BKR8EIX with no issues for a little while. The stock ones were fine too, and then the Brisk DR12YS which the car seemed to like best, but dont recommend if you wanted more longevity as these will probably need to be replaced even earlier than stock.

Even at DP, I you probably don't need colder plugs on a mild ratio.

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Thanks! I have a set of BKR8IX in a shopping cart. I'm glad to read your reply. Unless someone comes along with contra info, I'll order them tomorrow.

On other forced induction cars I've owned (all turbo, though), Iridium fine tip plugs have lasted longer on tuned engines with higher boost than platinum. I had to tighten gap up a bit to avoid boost gap blow out.

Maybe go to .024"?

[JeffSQuattro]

I know for IE, they recommended the BKR8 for DP and BKR9 for Stage 1 and Stage 2 SP. Most seem to be happy at .024-.026 @DP, running logs should help find a happy medium.


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[djn876]

Thanks! I have a set of BKR8IX in a shopping cart. I'm glad to read your reply. Unless someone comes along with contra info, I'll order them tomorrow.

On other forced induction cars I've owned (all turbo, though), Iridium fine tip plugs have lasted longer on tuned engines with higher boost than platinum. I had to tighten gap up a bit to avoid boost gap blow out.

Maybe go to .024"?

I run about .025, too much smaller and engine wasn't happy, when you do your logging you'll be able to tell.

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[MSq5]

I run about .025, too much smaller and engine wasn't happy, when you do your logging you'll be able to tell.

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Thanks. I'll probably start with .026", log and see about what that looks like. The platinum NGKs liked .026" better than .024", so I'll start there.

[MSq5]

I know for IE, they recommended the BKR8 for DP and BKR9 for Stage 1 and Stage 2 SP. Most seem to be happy at .024-.026 @DP, running logs should help find a happy medium.


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Are you sure about that? 9 range is colder. I would have thought 8 (same as stock as far as heat range), would be better for less aggressive tunes like stage 1 and single pulley, maybe even most dp, and reserve the 9 for super high boost and horsepower, like 3.5+ pulley ratio, larger throttle body, E40 ethanol, race gas, catless exhaust and such. But, I'm not as conversant with this engine as with others. Still learning. I'm afraid the 9s wouldn't self-clean at my power level and just foul badly.

[JeffSQuattro]

Are you sure about that? 9 range is colder. I would have thought 8 (same as stock as far as heat range), would be better for less aggressive tunes like stage 1 and single pulley, maybe even most dp, and reserve the 9 for super high boost and horsepower, like larger throttle body, E40 ethanol, race gas, catless exhaust and such. But, I'm not as conversant with this engine as with others. Still learning. I'm afraid the 9s wouldn't self-clean at my power level.

On Pg.17 of the IE thread this was recommended.

Personally I’ve been dual pulley for about 6k miles coming from IE Stage 1 with bkr9’s on about 17k miles in them. It runs smooth and no misfires are present. I have a set of bkr8’s that I’ll probably throw in soon. I’m on 91oct as well.

I was pretty thorough in my quest to choose a tuner/tune and I remembered this specific info lol.

I also came across a lot of good feedback on the Brisks, but the lifespan isn’t the greatest. Changing the plugs are pretty straight forward anyway.


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[JeffSQuattro]

On Pg.17 of the IE thread this was recommended.

Personally I’ve been dual pulley for about 6k miles coming from IE Stage 1 with bkr9’s on about 17k miles in them. It runs smooth and no misfires are present. I have a set of bkr8’s that I’ll probably throw in soon. I’m on 91oct as well.

I was pretty thorough in my quest to choose a tuner/tune and I remembered this specific info lol.

I also came across a lot of good feedback on the Brisks, but the lifespan isn’t the greatest. Changing the plugs are pretty straight forward anyway.


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Edit: Scratch what I mentioned, as I just noticed I have it mixed up by looking back at the post again. My apologies, the 9s appear to be for DP. 8’s for Stage 1 and SP


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[MSq5]

On Pg.17 of the IE thread this was recommended.

Personally I’ve been dual pulley for about 6k miles coming from IE Stage 1 with bkr9’s on about 17k miles in them. It runs smooth and no misfires are present. I have a set of bkr8’s that I’ll probably throw in soon. I’m on 91oct as well.

I was pretty thorough in my quest to choose a tuner/tune and I remembered this specific info lol.

I also came across a lot of good feedback on the Brisks, but the lifespan isn’t the greatest. Changing the plugs are pretty straight forward anyway.


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No problem. I suspected you just got the numbers reversed, but sometimes counterintuitive things work.

Familiar with plug changes on this engine - three times now, so it is pretty quick. I do all my own wrenching on all mods in my signature below. I just enjoy doing my own work. The issue is just which Iridium plug to run on my tune, pulley ratio and 93 octane. I'm going to order the Iridium 8s and see how they do.

I've been of the school to run the hottest heat range that is short of pulling timing to avoid detonation and the coldest possible short of fouling. One heat range fits both goals.

The trick is to look at the logs and find the sweet spot for heat range and gap. You're right that I can easily jump up to 9s if the logs don't look right. Thanks.

[Corydms7]

You realize the pfr plugs are laser platinum? Iridium doesn’t last as long as platinum.

[Corydms7]

I have my laser platinums gapped to .026”

[MSq5]

You realize the pfr plugs are laser platinum? Iridium doesn’t last as long as platinum.

Not so sure. On other high boost cars I've owned the platinum NGK plugs failed much earlier than Iridium. I understand that Iridium has a much higher temperature survival than platinum. The fine wire can be gapped tighter at very high boost levels to better fight boost spark blow out.

[JoeAWD]

I am DP, had the brisk plugs got about 10kmi out of them, switched to the BKR9EIX about 6kmi later got misfires again, just switch back to the Brisk plugs. I measured the gap on the old BKR9 plugs and some were over .029, they went in at .025. I think I will just change plugs every 6 months and stick with the Brisk plugs. The car feels faster with them (might just be a placebo effect, lol ), but $60 and 20min every 6 months is easy insurance.

[01northernS4]

I am DP, had the brisk plugs got about 10kmi out of them, switched to the BKR9EIX about 6kmi later got misfires again, just switch back to the Brisk plugs. I measured the gap on the old BKR9 plugs and some were over .029, they went in at .025. I think I will just change plugs every 6 months and stick with the Brisk plugs. The car feels faster with them (might just be a placebo effect, lol ), but $60 and 20min every 6 months is easy insurance.

When does one generally know or need to check the plugs on dual pulley and what are the advantages of setting a lower gap, colder/hotter plug, etc...?

Logged dual pulley Unitronic many times, always clean with no misfires... stock original plugs at 50,000km, stock gap, I'm guessing .032... which happens to be Unitronic's recommendation.

Also read a bit of the spark plug thread and can't imagine checking/changing the spark plugs is necessary unless you're experiencing misfires?

Many run stock gap and plug and recommend it with great results.

[01northernS4]

I have my laser platinums gapped to .026”

That's what I've read EPL suggests... but then many others say oem plug and gap (ngk .032") and/or run the biggest gap possible without misfiring... again, if no misfires any reason to check and regap?

Why is everyone trying to reduce their plug gap when I've generally read here run the biggest gap possible without misfiring? More power, smoother... Placebo?

Thanks again

[Corydms7]

That's what I've read EPL suggests... but then many others say oem plug and gap (ngk .032") and/or run the biggest gap possible without misfiring... again, if no misfires any reason to check and regap?

Why is everyone trying to reduce their plug gap when I've generally read here run the biggest gap possible without misfiring? More power, smoother... Placebo?

Thanks again

Here’s from NGK’s website:

“Many think the larger the gap, the better. However, if the gap is too large, and the ignition system can’t provide the voltage needed to spark across the gap, or turbulence in the combustion chamber blows out the spark, misfires will occur.”


The smaller the gap, the more efficient it is.

[01northernS4]

Here’s from NGK’s website:

“Many think the larger the gap, the better. However, if the gap is too large, and the ignition system can’t provide the voltage needed to spark across the gap, or turbulence in the combustion chamber blows out the spark, misfires will occur.”


The smaller the gap, the more efficient it is.

Interesting and thank you for this!

Looks like I may have to check and re-gap after all... so more accuratly is it the smallest gap without misfires?

Wonder why I've read the biggest gap possible with no misfires ... there must be some sort of benefit in running a bigger gap?

[djn876]

Interesting and thank you for this!

Looks like I may have to check and re-gap after all... so more accuratly is it the smallest gap without misfires?

Wonder why I've read the biggest gap possible with no misfires ... there must be some sort of benefit in running a bigger gap?

The bigger gap provides more available spark to ignite the fuel mixture. I would agree running a wider gap is better for spark exposure, but only if the setup supports it. My car didn't like it once the gap got too small. If the car isn't misfiring or knocking leave them alone, there will be no benefit in messing with them.

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[MSq5]

Once boost gets high enough with aftermarket tunes, it can actually blow out the spark under maximum load. Its called spark boost blow out. It's real. NGK is right. I've had it happen with high boost turbo engines. The trick is to close the gap down enough to avoid that, but not enough to cause misfires by not getting enough flame for reliable ignition.

The sweet spot will probably vary depending on mods, boost level and even cylinder-ro-cylinder depending on what logs show.

I'm going to try the BKR8EIX (should be here tomorrow) with .026" gap and see how they work.

[01northernS4]

Once boost gets high enough with aftermarket tunes, it can actually blow out the spark under maximum load. Its called spark boost blow out. It's real. NGK is right. I've had it happen with high boost turbo engines. The trick is to close the gap down enough to avoid that, but not enough to cause misfires by not getting enough flame for reliable ignition.

The sweet spot will probably vary depending on mods, boost level and even cylinder-ro-cylinder depending on what logs show.

I'm going to try the BKR8EIX (should be here tomorrow) with .026" gap and see how they work.

Another good explanation...

That being said, for all the folks running stock NGK plugs and stock .032" gap with no misfires, there'd be no reason to change anything or experiment, correct? Not like you will see more power or notice anything else?

Are you changing these gaps and plugs because you have misfires?

[MSq5]

Another good explanation...

That being said, for all the folks running stock NGK plugs and stock .032" gap with no misfires, there'd be no reason to change anything or experiment, correct? Not like you will see more power or notice anything else?

Are you changing these gaps and plugs because you have misfires?

If you are on stock tune, correct. If tuned, running higher boost and timing, follow the tuner's recommendation on gap, at least initially, if no misfires.

And, yes, I'm stage 2 dual pulley, have about 25,000 miles on these and am getting misfires now. They are worn out. Moving to Iridium in the same heat range from stock plugs hoping to get a longer mileage interval before changing next time. I don't expect greater power.

[01northernS4]

If you are on stock tune, correct. If tuned, running higher boost and timing, follow the tuner's recommendation on gap, at least initially, if no misfires.

And, yes, I'm stage 2 dual pulley, have about 25,000 miles on these and am getting misfires now. They are worn out. Moving to Iridium in the same heat range from stock plugs hoping to get a longer mileage interval before changing next time. I don't expect greater power.

Ahh got it.

I'm dp 3.2 ratio unitronic with generally no misfires on ngk at 0.32 gap (I think, never checked since new)

when I say generally I mean looking at misfires at idle and wot 99% time they are 0 but occasionally 1 or 2 misfires will randomly pop up across all cylinders

I've read unless it's consistent misfires, it's normal...

Approximately how many misfires are you seeing at idle and wot?

Just curious when I should start paying attention to this and change my plugs as they are currently at 50,000km stock plugs and I've been dp for 5,000km of that now.

thanks again!

[MSq5]

Ahh got it.

I'm dp 3.2 ratio unitronic with generally no misfires on ngk at 0.32 gap (I think, never checked since new)

when I say generally I mean looking at misfires at idle and wot 99% time they are 0 but occasionally 1 or 2 misfires will randomly pop up across all cylinders

I've read unless it's consistent misfires, it's normal...

Approximately how many misfires are you seeing at idle and wot?

Just curious when I should start paying attention to this and change my plugs as they are currently at 50,000km stock plugs and I've been dp for 5,000km of that now.

thanks again!

Correct. It's not unusual for a log to show a few misfires. I see just about none at idle, maybe, like you, a couple random.

What I'm now experiencing are misfires serious enough to throw a code and cause sputter that can be felt. Twice in the last two weeks it has stumbled at wide open throttle right before upshift rpm in third gear requiring me to get out of the throttle - acting like boost blow out. So, I'd not be surprised to find out that gap has opened over time. Each time I did a full scan and the only errors reported were random misfires. They were gapped at .026" per EPL recommendation. They just wore out. Stage 2 tunes are just hard on plugs.

[djn876]

Correct. It's not unusual for a log to show a few misfires. I see just about none at idle, maybe, like you, a couple random.

What I'm now experiencing are misfires serious enough to throw a code and cause sputter that can be felt. Twice in the last two weeks it has stumbled at wide open throttle right before upshift rpm in third gear requiring me to get out of the throttle - acting like boost blow out. So, I'd not be surprised to find out that gap has opened over time. Each time I did a full scan and the only errors reported were random misfires. They were gapped at .026" per EPL recommendation. They just wore out. Stage 2 tunes are just hard on plugs.

Could be plugs but that sounds a lot like leaking intercooler too. My plugs were always clean when mine was leaking. Was surprised at how much gunk had built up without any other indications on the plugs and things and coolant loss was very small and hard to detect.

When you say misfire do you mean you are logging misfire counts, or are you referring to knock detection?

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[MSq5]

Could be plugs but that sounds a lot like leaking intercooler too. My plugs were always clean when mine was leaking. Was surprised at how much gunk had built up without any other indications on the plugs and things and coolant loss was very small and hard to detect.

When you say misfire do you mean you are logging misfire counts, or are you referring to knock detection?

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Just installed the NGK BKR8EIX plugs, gapped to .026". Zero misfires. Logging misfire counts. Pulls hard. 7k upshift 3>4 is flawless. I'll try a Dragy run tomorrow. I understand that it may take time for a leak to affect the new plugs.

All old plugs were normal looking except for what seemed accelerated wear on the ground strap. No fouling, expected black soot, though. All were dry, no evidence of IC leak. Gap had not opened appreciably, though. Still at .026"-.028", closer to .028" on most.

For those interested, the BKR8EIX plugs are technically for another application and come gapped at .032". I closed them to .026". Note: gapping Iridium fine wire plugs must be done very carefully to avoid scraping or damaging that fine center electrode tip. I learned this lesson the hard way years ago on another platform that came with NGK Iridium plugs OEM.