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Discussion Starter #1
This is the first time I have ever come across this situation. I literally checked every auto parts store in my area and no one has spark plugs in stock. What I’m looking to do is get Copper core plugs rather than Iridium. It is a common misconception that more expensive plugs do a better job. This is untrue. Out of all the materials used to make spark plugs, copper is the best conductor. What all of these other materials have been used for is longevity. So, if you’re not scared of a little work every once and a while, then replacing plugs with copper plugs and changing them at an appropriate time interval is actually beneficial. Has anyone done this yet? And if so, do you have the brand and part number that you used. I’m also thinking of trying to find one step cooler plug.
 

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Consider this, your changing your Iridium plugs already and you car has what 20K Miles? Those plugs last upwards of 70K miles, a copper plug is probably
only going to last 4-5K Miles then so you will need to swap them out nearly every oil change.

Not worth the effort I'd at least stick with Iridium, although spark plugs are very much a "OEM only" part in my books. If I was going
to swap to any other brand it would be NGK.
 

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Discussion Starter #6
Consider this, your changing your Iridium plugs already and you car has what 20K Miles? Those plugs last upwards of 70K miles, a copper plug is probably
only going to last 4-5K Miles then so you will need to swap them out nearly every oil change.

Not worth the effort I'd at least stick with Iridium, although spark plugs are very much a "OEM only" part in my books. If I was going
to swap to any other brand it would be NGK.

I believe (from my research) the OEM plug is NGK. I understand thinking to stick with OEM, however if you do a little bit of spark plug research, you will find that it’s not that big of a deal. Also. When increasing power output of a given engine which increases heat, there are benifits to running one step colder plug. Also, copper plugs are not going to die every 5k.
They should last about 20k however I will probably change them every 10-15. At only $3 a plug, it’s no biggie for the added conductivity.
 

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I believe (from my research) the OEM plug is NGK. I understand thinking to stick with OEM, however if you do a little bit of spark plug research, you will find that it’s not that big of a deal. Also. When increasing power output of a given engine which increases heat, there are benifits to running one step colder plug. Also, copper plugs are not going to die every 5k.
They should last about 20k however I will probably change them every 10-15. At only $3 a plug, it’s no biggie for the added conductivity.
Hmmm Infiniti used Denzo on their 3. 7L, I've not looked into the 3.0TT but if they use NGK then great they are arguably one of the best brands.

I suppose my last post wasn't very clear with the changer interval, I recall a few people saying they swapped the Iridium plugs out around 25-30K and they
were in pretty bad shape. If Iridium plugs are needing to be swapped out that soon can we really expect a copper plug to last their rated 15-20K miles?

If you want to swap them go ahead but keep a close eye on how quickly they are wearing out,
 

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I switched to copper plugs in my G8 GT. They do indeed work a bit better but about 10K - 15K miles is it. They are a LOT easier to change out in that small block motor VS. the Infiniti. I don't think the slight edge they provide would be worth the hassle. YMMV
 

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The more times you swap plugs the more chances of effing up something (such as a cross threaded plug). I'm not sure how many things have to come off the 3.0 to access the plugs, but because of access issues I changed plugs in our three Subarus exactly zero times (had the dealer do it). Some things in life just aren't worth my coming up with more new combinations of swear words.
 

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Discussion Starter #11
I switched to copper plugs in my G8 GT. They do indeed work a bit better but about 10K - 15K miles is it. They are a LOT easier to change out in that small block motor VS. the Infiniti. I don't think the slight edge they provide would be worth the hassle. YMMV
Supposedly, it’s juat a few bolts for the intercoolers, and you move them out of the way, and then it should be as easy as an LS. Also, I have read that iridium doesn’t last 100k like they suggest in a forced induction application. “They” (lol) are saying 25-30k. So sure. I will go through twice as many as an iridium car probably or maybe a little more. But, for the “edge” as well as the added personal reassurance (which is really what I’m after)by doing it more often, I will be happy to do a little more work. Also, on top of all of the above, I really cannot get myself to purchase a lesser performing product for 3-6 times the money (depending on the plug.
 

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Copper spark plugs have a copper core but the working end of the center electrode is coated with a nickel alloy as is the tip. Since a copper plug's center electrode is 2.5 mm and much larger than platinum or iridium plug's electrodes, it requires more voltage to create an equivalent spark. Since the Q50's ignition system is designed for iridium plugs (fine wire center electrode) I wonder if switching to copper core plugs may cause performance issues because of this.

The consensus of articles I've read state not to downgrade to copper core plugs if your car is designed to run with platinum or iridium plugs as it will diminish the performance. Perhaps initially, a copper plug would work better. However, the soft electrode tips will degrade faster and when coupled with a higher voltage demand than an iridium plug requires I suspect a significant portion of time during the lifetime of the copper plug, it's performance may not be as good as an iridium plug.

All that being said, it won't hurt to try them and see what you experience. I'm not going to be changing spark plugs myself so the longer interval between iridium plug changes is preferable to me. I'd certainly like to hear about the alleged performance improvement if you choose to do this. It shouldn't hurt anything but I just don't think you are going to get the improvement that you think is going to happen.
 

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Discussion Starter #15
Copper spark plugs have a copper core but the working end of the center electrode is coated with a nickel alloy as is the tip. Since a copper plug's center electrode is 2.5 mm and much larger than platinum or iridium plug's electrodes, it requires more voltage to create an equivalent spark. Since the Q50's ignition system is designed for iridium plugs (fine wire center electrode) I wonder if switching to copper core plugs may cause performance issues because of this.

The consensus of articles I've read state not to downgrade to copper core plugs if your car is designed to run with platinum or iridium plugs as it will diminish the performance. Perhaps initially, a copper plug would work better. However, the soft electrode tips will degrade faster and when coupled with a higher voltage demand than an iridium plug requires I suspect a significant portion of time during the lifetime of the copper plug, it's performance may not be as good as an iridium plug.

All that being said, it won't hurt to try them and see what you experience. I'm not going to be changing spark plugs myself so the longer interval between iridium plug changes is preferable to me. I'd certainly like to hear about the alleged performance improvement if you choose to do this. It shouldn't hurt anything but I just don't think you are going to get the improvement that you think is going to happen.
Lol, I think I read the EXACT same article as you today. That is one thing I didn’t take into consideration at first (the amount of energy needed from the ignition). A big part of what I was going off of was with high performance bikes, it was suggested to use copper and just change frequently and that was to rev to 15000. Also when adding a high energy ignition system. One thing that is for sure, it is said to be a benifit to run one level colder plug when raising hp 75-100 above stock. More research needed for sure.
 

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As stated, the NGK P/N for the VR30DDTT is DILKAR8K8G.

I found the hotter and colder plug (er, candles, LOL) P/Ns in an obscure Russian data page on the interwebs:

For engine modifications:
Nissan, VR30
Candles (marking)
NGK, DILKAR8K8G (stock), DILKAR7K8G (hotter), DILKAR9K8G (colder)[/I]

The stock "8" heat range can be found for purchase, but the colder/hotter plugs are nowhere in the retail market, based on my searches.
 

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Off topic but, has anyone tried using GTR spark plugs?
What is special about GTR plugs? Seriously. Or am I missing a joke here?
 

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Discussion Starter #20
What is special about GTR plugs? Seriously. Or am I missing a joke here?
There can be slight differences in the plug design that can be beneficial in higher hp situations. For instance, sometimes the ground strap is shortened to help it dissipate heat better. But without having all of the specs in front us/ having the plugs physically in hand to compare. It’s hard to know. I saw a guy say he put GTR plugs in. But this doesn’t mean it’s a good idea. Necessarily.
 
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