[califcarm]

I am running iridiums, with MSD 6a, I found my coppers were increasing gap quickly to like .034+, so I thought I'd try the iridiums, and recently dyno'd 300whp@17psi still on stock ecu (gen2) with about 7000km on the plugs... and no hesitation. So I think I might be converted just for the consistency and longevity.

Yes, I could see the benefit with the MSD 6A. Multiple firing events instead of singular for all low rpm and part throttle driving could wear out coppers much faster than otherwise would happen with a stock ignition like mine.

 

[Luni]

On my last MR2, I couldnt run stock heat range with my boost turned up, even if I had them gapped down.

Ive been able to get over 300whp on 6 range iridiums. Ive also been able to get more than 30k miles out of a set of plugs.

Given the fact Im not blowing spark out, Im not misfiring, or any ignition related issues, I have to conclude that for me, in my experience, the iridiums beat the pants off the coppers. They ran better at more gap, they lasted longer, required much less maintenance, got more performance with a given heat range, and in the end, due to not having to replace near as often, resulted in less money spent.

For 90 percent of the bros on here, the iridiums are better than the coppers. If youre one of the guys out there that is replacing your spark plugs every 3k miles when you change your oil, youre throwing your money away and being wasteful. You should try some iridiums.

If you have, and you didnt like them, Id be interested in finding out why.

 

[^Trickster^]

I used to run the copper plugs, but they didnt tend to last, i tried ik24 and they fell apart!

I have used bkr8eix ngk iridiums for eyars now and never had an issue

Graeme

 

[WhiteShark]

on the ngk iridium, what gap do you guys gap it at, stock or .028?

 

[^Trickster^]

0.6mm here

 

[3sgtemr2t]

Exactly.

820+whp on BKR7E plugs on my MR2.

Aaron

Wowzers

 

[Gandalf]

on the ngk iridium, what gap do you guys gap it at, stock or .028?

I checked them (bkr7eix) and they were all the same out of the box, and they were all at .030 or .032 (can't quite remember), so I left them as is to see how they would do. No issues. But like I said I am only at 300whp and 17 psi with MSD 6a, stock ecu.

Here is an earlier thread of mine regarding "growing gaps" on my BKR7E's. Not uncommon for them to increase .006

I agree that it comes down to how often things are getting taken apart anyway, and how often people want to be changing/gapping plugs.

 

[Luni]

I dont gap mine. Im pretty much scared to. Too many stories of people breaking ground straps or insulators.

never had a problem.

 

[Gandalf]

^That's what I was going on, if it ain't broke don't gap it lol

I am curious to see if the gap changes over time on these though.

 

[Gandalf]

Update: absolutely no change after 10,000 km on the Iridiums. They look perfect. They began to miss last week.

Edit -
2nd UPDATE:
I think I was previously just at the threshold for power without miss using my MSD setup, with .033 gap, and the stock ecu, producing 300whp @ 17 psi.
Because I am tuning with a new setup, the power increase now demands a smaller gap. I threw in coppers at their stock gap of .033 or so, they also developed the same miss, even worse actually, within a couple of days. Regapped them @ .028, and it worked.


Edit -
3rd UPDATE:I threw the Iridiums back in regapped to .028, and they still missed.

 

[Luni]

Wait.

They look perfect, but they began to miss?

So are they OK or did you only get 10k km out of them?

 

[benckj]

Curious as well on why they would miss. I'm still on the copper diet but wanting to try Iridiums as I have a strange intermittant miss I can't put my finger on.

jim

 

[Gandalf]

Wait.

They look perfect, but they began to miss?

So are they OK or did you only get 10k km out of them?

Exactly. There was no visually identifiable reason (gap, coloration, build-up, good tips, etc)... they were installed in 2012, got 10,000+ km out of them (I don't put dd miles on the car), and the gap was identical to when installed. That's pretty good in my books. How much mileage do you typically see from your plugs?
I have the MSD 6A ignition, so they probably see a more challenging environment with multiple sparks at low RPM.

Considering I always had to fiddle with the coppers (widening gap after only 2000km), I'm temporarily trying coppers now and leaving them stock gap (.033), until I pick up some more Iridiums.

Jim, I would swap out the plugs first, if your miss is still there, throw the older ones back in, no harm done and you can still use the new plugs when the time comes. I haven't had issues with the crush-washers leaking on re-use AFAIK. My miss drove me nuts this past week because I was working on timing/boost and I didn't know what was holding me up, lol. What do you know, Iridiums aren't invincible

Edit - UPDATE:
New-found power is demanding a smaller gap.

 

[Luni]

^ Ive got over 30k on a set of 7 range iridiums on a BPU Gen2 with a 20b.

I only changed them because I was "worried" about them breaking or whatever. They worked fine.

 

[Gandalf]

^Excellent.
I think the MSD + racing/tuning just takes its toll... And I'm 100% certain it was the plugs, it was the only thing changed; and the miss issue was resolved within 10 minutes, so all other conditions remained the same, and stayed that way since.

Tempting to do a comparison of the two plugs, and gaps (maybe bigger like .038) next time on dyno, I like to read the plugs whenever I get moderate knock on the J&S, to see if one cyl is worse than others.

Edit - UPDATE:
I think I was previously just at the threshold for power without miss using my MSD setup, at .033 gap, and the stock ecu, producing 300whp @ 17 psi.
Because I am tuning with a new setup, the power increase now demands a smaller gap. I threw in coppers at their stock gap of .033 or so, they also developed the same miss, even worse actually, within a couple of days. Regapped them @ .028, and it worked.
I threw the Iridiums back in regapped to .028, and they still missed... it was their time.

 

[Smurfcrusher]

^Excellent.
I think the MSD + racing/tuning just takes its toll... And I'm 100% certain it was the plugs, it was the only thing changed; and the miss issue was resolved within 10 minutes, so all other conditions remained the same, and stayed that way since.

Tempting to do a comparison of the two plugs, and gaps (maybe bigger like .038) as an aside when I hit the dyno in the next couple of weeks.

I've had great luck with Iridiums too. Haven't experimented with gap yet, I'm running COPs and suspect I can increase it. Running 18 PSI now.

 

[dobosininja]

I checked my iridium's today after having them in for a year (approximately 8-10k miles). They were a little loose in the socket, but overall the center conductor's looked good. I put them back in, and I will see how they look next year.

I have the 6's in mine now as it is a stock 3rd gen, but I might throw some 7's in once I put on a 3" downpipe and aftermarket intercooler for higher boost.

 

[Gandalf]

I haven't touched gap on any Iridiums yet, they look a bit delicate to pressure the tips, avoid putting pressure there if you try to gap them. I'm going to experiment on copper gaps.

 

[Luni]

I checked my iridium's today after having them in for a year (approximately 8-10k miles). They were a little loose in the socket, but overall the center conductor's looked good. I put them back in, and I will see how they look next year.

I have the 6's in mine now as it is a stock 3rd gen, but I might throw some 7's in once I put on a 3" downpipe and aftermarket intercooler for higher boost.

Not saying you SHOULDNT run 7s, but Im running 6s in a highly BPU Gen3. I have GSC 268 high lifts cams, IMEC sports ECU, Blits K1-380v turbo, 3inch DP/exhaust all the way back, intercooler, EBC set at ~17 PSI at 4800 feet of elevation. (Elevation matters - thats why I listed it)

I have never had an ignition issue in this engine. Ideally spark plugs are a fine line. You want the coldest plug you need without preignition, but you also want the hottest plug you can use without preignition so it self cleans.

 

[Gandalf]

UPDATE:
I think I was previously just at the threshold for power without miss using my MSD setup, .033 gap, and the stock ecu, producing 300whp @ 17 psi.

The coppers I just installed at their stock gap of .033 or so, they also developed the same miss, even worse actually, as of yesterday. I am pushing a bit more boost now though, topping out at about 19 psi (94 octane, J&S knockguard and tuning help me against knock)

Because I am tuning with a new setup (EMS, 1050cc injectors etc) the power increase now demands a smaller gap. Regapped them @ .028, and it worked.

I threw the Iridiums back in regapped to .028, but they missed still. It was just their time.

So there's some data regarding gap + MSD.

I added edits to my above posts, otherwise they can be misleading.