NGK Iridium IX spark plugs

[jay340S4]

So I picked up a set of these for a great price and was wondering if anyone else was using these and if you have had any problems. I did search but there was not much about them on the S4.

[NOTORIOUS VR]

I know a few people that use them... not on an S4, but in high boost applications... they do very well and last long. I would get them over the Bosch plugs any day... but then again I'm biased towards NGK. They're a great plug manufacturer IMO.

I've seen the Iridiums do amazing things when copper plugs wouldn't cut it (high compression and high boost methanol applications)... went from not wanting to rev/boost to pulling right through to redline with nothing more then swapping out the plugs to Iridiums on the dyno (and before the session started a fresh set of coppers went in)

[racer56]

NICE choice on plugs. I was actually going to post soon, because i have a B6 A4 i want to buy the NGK Iridium plugs for. My car has a APR stage 1 ecu but everything else is stock. I was told that the Iridium spark plugs would go a long way in my car is that true or is it over kill?

[jay340S4]

The ones I bought were BKR6EIX. Do they need to be gaped or will they be fine out of the box. I have been looking around but haven't been able to come up with a solid answer for the B5 S4.

[BITRBO]

I know a few people that use them... not on an S4, but in high boost applications... they do very well and last long. I would get them over the Bosch plugs any day... but then again I'm biased towards NGK. They're a great plug manufacturer IMO.

I've seen the Iridiums do amazing things when copper plugs wouldn't cut it (high compression and high boost methanol applications)... went from not wanting to rev/boost to pulling right through to redline with nothing more then swapping out the plugs to Iridiums on the dyno (and before the session started a fresh set of coppers went in)

That's interesting, because Copper has like 3X the electrical conductivity and 2.5X the thermal conductivity of Iridium, so spark should not have been an issue with the Coppers. Are you sure they both had the same heat range? Cause if the Copper was only 1 step colder and Iridium was 2 or more, then the colder heat range plug would obviously hold up better under high-boost, high combustion chamber temperature conditions... Or did the two plugs have the exact same gap and electrode/ground configuration? Cause even the smallest alterations in electrode length, angle, number of ground prongs, distance to intake valve, etc., etc. can effect spark under high-boost applications (read spark blowout). But all things being equal, there shouldn't have been that much of a difference by just changing plug material.

OP, I've ran Iridiums in the past trying to chase down a ghost misfire cause I heard they were good for that (still not sure why, but W/E), and it seemed to help for a while... But then again that just may have been the placebo effect going from some semi-used Coppers, so IDK. I'm going to switch back to the cheap NGK Coppers real soon just to see what happens, and I'll make sure to report back.

The bottom line is: Platinums (which you shouldn't really use on t/c'd or s/c'd cars) and Iridiums are generally recommend if you're looking for a long service life out of your plug. That's why BMW and other manufacturers with included-maintenance packages use Platinum... The plugs usually last 40K+ so the Dealerships don't have to change the plugs within the maintenance period.

Copper plugs are cheaper and are actually great plugs for high-HP, high-power ignition applications, but due to the material properties (softness) they tend to wear out more quickly, thus requiring more frequent changes...(for comparison, Iridium is 6x harder and 8x stronger than Platinum, and Platinum is like double that compared to Copper IIRC). That being said, there are a lot of people on here running the cheap Coppers on their stage III's and just change them every (or every other) oil change, so it really comes down to the User preference.

GL!

[J-b5]

for the 100th time.

In the case of NGK plugs... ALL the cores are copper.

the tips are iridium on the iridium plugs.

the tips are platinum on the platinum plugs.

the tips are nickel on what you guys call the "copper" plugs. They are not copper. Copper is not durable enough to be used as the tip of a spark plug.


Not all "copper" spark plugs will have even the slightest amount of copper, and certainly will not have a copper tip. Not ever.

[BITRBO]

for the 100th time.

In the case of NGK plugs... ALL the cores are copper.

the tips are iridium on the iridium plugs.

the tips are platinum on the platinum plugs.

the tips are nickel on what you guys call the "copper" plugs. They are not copper. Copper is not durable enough to be used as the tip of a spark plug.


Not all "copper" spark plugs will have even the slightest amount of copper, and certainly will not have a copper tip. Not ever.

You are absolutely correct sir, and I appologize for not clarifying that myself... However, as you may know Nickel is just as bad as Platinum regarding conductivity, so they are only used on the tips where 99% of the erosion occurs. Copper plugs still have Copper cores, which theoretically makes it a better conductor than a Platinum or Iridium plug with homogeneous cores (all things being equal).

[J-b5]

You are still under a slight misconception.

the nickel tips are still bonded to the copper core much the same way as the iridium and platinum tips. Their performance advantage does not come from any conductivity increases as we technically are dealing with voltages that are capable of jumping an air gap with considerable resistance to current.

We are still dealing with a little lump of nickel, platinum, etc, bonded to a copper core. Any differences in the conductivity are relatively small due to the size of the conductive tip and mass of material. Platinum and iridium are better conductors, and have higher heat resistances. Thus they are less likely to vapour off during the intense heat created at the moment of spark. Note, not the moment of combustion as that operates at relatively low temperatures. But the spark itself generates highly localized MASSIVE heat.

Remember spark plugs are not wearing down because of fuel ignition, they are being blasted off, millions of particles at a time every time the spark jumps. this is plasma people. High energy stuff.


Anyways. You get longevity and whatnot due to the durability and high melting point of the exotic metals. Nickel is a little more mundane and easy to boil off so they dont last as long.


Why or why they dont work better is a matter for people better educated than I am, but I the explanations that I have heard deal with the fact that the spark event is not a single arc but a pulse of several in a row. And that the air in the path of the spark becomes ionized and thus becomes more greatly resistant to conductivity. A broader shaped electrode as opposed to a fine tip theoretically allows the next spark in series to follow a different path through the air more easily.

This is why you see these plugs with multiple grounds. Allows the spark to take the path of least resistance, and broadens the initial flame front by igniting it over a slightly larger area.



The theories are all fine and dandy. But if your cool looking multi prong wonderplug has a shit conductor in it, overheats, and drops its ceramic, well the .5% better flame front it produced doesnt mean squat.

As far as I know NGK makes good quality plugs that are selected as OEM for audi. Bosch continuously gets tried and rejected by the manufacturer. Often used during initial production, then later switched out for NGK and pulled from the shelves for replacements.













*** dont take my word it though... Im just a dabbler like the rest of you.

[NOTORIOUS VR]

That's interesting, because Copper has like 3X the electrical conductivity and 2.5X the thermal conductivity of Iridium, so spark should not have been an issue with the Coppers. Are you sure they both had the same heat range? Cause if the Copper was only 1 step colder and Iridium was 2 or more, then the colder heat range plug would obviously hold up better under high-boost, high combustion chamber temperature conditions... Or did the two plugs have the exact same gap and electrode/ground configuration? Cause even the smallest alterations in electrode length, angle, number of ground prongs, distance to intake valve, etc., etc. can effect spark under high-boost applications (read spark blowout). But all things being equal, there shouldn't have been that much of a difference by just changing plug material.

I'm almost certain that the 'copper' plugs were the same heat range as the Iridiums, what I do know is they Iridium plugs that were swapped in were a used/shop set that were just kicking around.

[BITRBO]

Speaking of misconceptions, I can agree with almost everything you said but this:

"...Platinum and iridium are better conductors..."

Can you please provide some sort of legitimate resource that proves this statement? I'm sure the electrical engineering community would be VERY interested to hear this too...

[BITRBO]

I'm almost certain that the 'copper' plugs were the same heat range as the Iridiums, what I do know is they Iridium plugs that were swapped in were a used/shop set that were just kicking around.

Well, almost certain and not is 100% off too j/k

But seriously, even 1 heat range would've made a big difference... Also, and as J-b5 so eloquently eluded to; Due to the superior material strength properties of Iridium versus Nickel and even Platinum, plug manufacturers can make the electrode much, much thinner than they used to, and therefore have much more room in the spark path for alternative ground-to-electrode configurations... There is so much going on within the spark "zone" between the ground and the electrode (and within the combustion chamber itself) at the time of detonation, that seemly minor variances in plug tip & ground design can greatly affect detonation effectiveness and efficiency (perfect example: gap).

In other words, it could have been that the Iridium's just had a better tip configuration than the Coppers and were able to prevent blowout under extreme combustion chamber pressures.

[csosnowski]

Ive run the BKR6EIX plugs and swapped to the BKR7E plugs due to a random misfire and the fact that the car didnt seem smooth after putting in the IX's. It was fine when I first put them in, but that could have been the difference between the aged PFR6Q's that I pulled out and a brand new plug.

I ran into a similar issue in my wife's 1.8 while chasing a miss that turned out to be a fuel injector related issue, but nonetheless, the PFR6Q's ended up being what that engine liked more than either the standard or the IX. It is stock though so that could factor in somewhere.

Does anyone have any information regarding the effect of the difference in resistance between the BKR7E/BKR6EIX and the PFR6Q?

I tested each with a meter just for fun and the BKR's came out to be a 5k ohm resistance and the PFR's were 1k.

Can this have any effect on the strength of the spark or longevity/stress of the coils?

[J-b5]

Speaking of misconceptions, I can agree with almost everything you said but this:



Can you please provide some sort of legitimate resource that proves this statement? I'm sure the electrical engineering community would be VERY interested to hear this too...

Im pretty sure i didnt mean to suggest they are better conductors than copper. I meant nickel. The main reason they are used is durability, second to being good conductors.

here is a nice table that lays out some basic stuff for a variety of metals
http://www.engineeringtoolbox.com/re...ity-d_418.html

[J-b5]

I tested each with a meter just for fun and the BKR's came out to be a 5k ohm resistance and the PFR's were 1k.

Can this have any effect on the strength of the spark or longevity/stress of the coils?

Actually yes. Thats really good info to have out there. The mustang guys have been having a hell of a time with spark plugs on their newer 4.6s (like 05+) seems they are very sensitive to high impedance plugs, and the aftermarket replacements are causing huge spark and misfire issues.

Of course they are so cheap they are going out and buying 2 dollar autolights for their supercharged cars, and wondering why all hell is breaking loose...

[J-b5]

heres a good little table for melting points etc.

[BITRBO]

And here's a good one for thermal & electrical conductivity:

[J-b5]

You can see how much better iridium is than platinum and nickel. Too bad silver is such a soft metal. :)

[jay340S4]

What is the best gap to have with these plugs?

[jay340S4]

nobody knows or has an opinion or suggestion? Any help would be much appreciated.

[NGKTECH]

Hey guys this is Brandon, I'm the U.S. tech support rep for NGK USA. This is a really good thread so far.

The PFR6Q and the BKR series plugs come factory gapped between .028-.032" on modified applications you may want to set them to the low side of the spec and possibly even lower if you experience any spark blowout.

For mild applications where the stock heat range can still be used I usually recommend sticking witht he PFR6Q both because of it's lower 1K ohm resistor and also because it has a copper core in the ground electrode which helps to keep ground electrode temps down and to increase service life by reducing wear from oxidation.

As one of you posted earlier there is no such thing as copper plugs as all standard plugs are made of nickel-alloy with a copper core. Iiridium, platinum, gold-palladium etc they also have that same copper core.

[S4James]

What of those of us running near 500chp with aggresive timing, meth, boost, etc?

the bkr7e-ix gapped down to .026 seems to be a popular choice, but what about some of your resistorless race plugs with non-projected tips?