luanda

Can someone help me find the part no. please?? The NGK site just tells me the stock part no.

I understand that copper is still better than iridium for FI - just expect to change them out sooner. How often should you replece these copper ones?

Thanks in advance.

luanda

Anyone? I've actually contacted NGK Tech. Support and the guy said they make copper plugs anymore...is that true??

protocav

iTrader: (3)

i am guessing it would be LFR6A-11 for copper that is 1 heat range colder.

stock is PLFR5A-11 (with the P indicating platinum)

sbcbaseball

iTrader: (4)

Hey Protocav you should of answered with that is a good question..hahaha

Sharif@Forged

iTrader: (92)

I sell the sets for $65 shipped, and I can pre-gap them for you...since they are extremely hard to gap without breaking the tips. You need a good gapper tool.

luanda

$65 for the copper ones, or are they iridium?? I thought copper would be a less than that...

mcduck

I think GQ is pimping the Iridium ones. The Copper ones should run you about 1/2 of that from any autoparts store (though they may have to special order them for you)

I first ran copper, then iridium. Now, I've gone back to copper. What I found is that the iridium ran no stronger and lasted no longer than my original copper set. Either was good for about 10K miles. Maybe you could clean up the Iridiums and get some more life out of them, but if I'm going to the trouble to replace plugs I'll go ahead and put fresh ones in.

BTW, if you're FI, you probably want to run a slightly narrower gap than factory recommends as well.

Sharif@Forged

iTrader: (92)

^^Correct^^ I was refering to Irdiums. I dont stock the coppers, but like McDuck said, you should find those at any car parts store.

As long as you use a cooper 1step colder, I dont really see any problems at moderate boost levels. Iridums are designed to last longer, and are definately stronger, and hold up better to higher cylinder temps. But since you are unlikely to ever see 2000degree cylinder temps, they might be overkill. I have used them since the begining of my F/I journey, and I tend to stick with what works for me.

I like to gap the Irdiums at .030 for F/I use. THe Iriduims come with a giant .040-.045 gap.

I currently have two sets in stock, and 6 more sets coming in 2 weeks.

sbcbaseball

iTrader: (4)

Question for you GQ626. How often do you change your spark plugs?

phunk

iTrader: (21)

14 psi of boost on iridiums gapped over .040.... along with the smoothest FI 350z dyno graph of any Z i seen. Not sure why people are bringing their gaps down. I expect to get at least a few more psi before having any spark blow out.

Coil on plug ownz jooo

theking

iTrader: (3)

I was wondering just how over engineered our ignition was! LOL.

luanda

Well I had a chat with the NGK Office here in Canada - It turns out they don't distribute the nickel/copper plugs in Canada anymore - just platinum or iridium. He was really pushing the iridium, claiming they would last 50K in a built FI engine. He also said the other advantages of the NGK irdium plug is that the negative electrode "Arm" was much beefier / stronger, and that the electrode is designed to allow the spark to ignite off a wider degree off-centre which further adds to the life of the plug.

He also suggested running a plug two steps cooler versus just one. Don't know if that's overkill or not. What are the pros and cons??

Anyone care to comment??

To someone's earlier question about our ignition system, I asked 2-3 independent tuners about whether an ignition amplifier product would help our cars (HKS, MSD has some). The feedback in all cases is that the new Z has a beefy stock ignition - lots of juice, and that our money would be spent better elsewhere.

Hey shariff what gap do you use on your Iridiums, would $65 cover shipping to Canada?? How often so you recommend changing them for FI??

Thanks....

Sharif@Forged

iTrader: (92)

I check them about every 5000 miles, and honestly, I tend to be really nerdy and will change them , even if they are fine. My first set ran for a pretty clean 10000 miles. Plugs are so cheap that I like to change them more frequently.

Blowing out a spark on the 350Z with its DIS coil over plug system is pretty slim. But in boost, in doesnt hurt to run slightly smaller gaps.

Spark plugs are like oil changes, and everyone will have an opinion on what is best. Just do what you feel comfortable with, as I am telling people what has working for me.

phunk

iTrader: (21)

larger gap = more effective burn... its probably part of the reason my graphs are so smooth. if i understand correctly it has a similiar effect as more ignition timing to by having a larger spark creating a larger initial burn, and probably resulting in a faster burn rate... but what do I know!

Sharif@Forged

iTrader: (92)

All thinks being equal, a larger gap gives more power, but the power increase is minimal. I have run .040 gaps, and .030 gaps and never noticed a change in graph smoothness.

Personally, I'd rather run a slightly tighter gap, and eliminate the risk of spark blow out, rather than run a larger gap for 1% more power..if that.

phunk

iTrader: (21)

Last year for a day I swapped out my stock original plugs for one step cooler with .030 gap. I lost 15hp and gained it when I put my old plugs back in :shrug: maybe just coincidence

mcduck

This is very sound advice. With an FI motor, checking plugs every 5000 miles is a good maintanence policy. I've actually started checking them out each time I change the oil.

To throw in my .02... I'm running 1step colder Copper with a .035 gap and I cannot tell a difference at all between this and when I was running .044 (which I think is the factory recommended specs)

luanda

Thanks everyone, I really appreciated all the input and help. I ordered a whack of nickel/copper NGKs, one-step cooler (LFR6A-11) and will change them out every 6K km with the oil....figure that's my best option.

I figure two steps colder is overkill, as I have no intention of getting much beyond my 400whp.