NGK Iridium Plugs

[Izento]

So, after installing the iridium plugs from the Pulsar NX SE 88', I have been getting bad stumbles. The pre-gap on the NGK website says .044, is that what it should be at for my CA18DET? Light mods such as poncams, intake, FMIC have been done.

[float_6969]

Iridiums weren't a great idea. They aren't usually adovocated for boosted cars as the very small tip can get hot under boost and become a point of pre-ignition.

As for the stumble, stock gap on a stock motor is .044 IIRC. If you're on the stock turbo at stock boost with those mods, the stock coil packs should be fine. I'd say you've either got a failing coil pack, or a failing ignition amplifier.

[TheMAN]

iridium and platinum plugs require greater voltage to arc, if you're running on 20+ year coils, don't expect anything!
iridium plugs do offer higher heat resistance and lower wear from the higher combustion temperatures, with properly working coils and gap, these plugs can outlast regular nickel/copper alloy and platinum plugs, offering consistent performance throughout its service life... the smaller tip actually reduces the chance of pre-ignition due to smaller quench area and less secondary sources of hot spots all around.... you can still achieve this with platinum plugs of course, with some loss of service life

nickel/copper alloy plugs wear faster on boosted engines due to high heat... the metal becomes softer under those higher combustion temperatures

that's the main reason why the CA18DET came with platinum plugs stock

[Liquid_Neon]

Skip the irids... I had the SAME problem on my pulsar. swapped to plats like they have factory, havent had a plug problem since. pulsar SE all have plats in the ca18de motor.

[Izento]

Thanks for the responses guys. Looks like I'll switch to plats after I check the gap on these Iridium ones.

[TheMAN]

gap those plugs to .028 first and see if they work right

[Izento]

Alright, so I checked the plugs and they were gapped to factory, so I bought some new platinums and they work fantastic. I guess either my worn down coil packs don't like iridiums or maybe CAs just hate em. Anyways, thanks for the heads up guys.

[Liquid_Neon]

I think it has something to do with the iridiums being a colder burn, mine would load up with fuel and started fouling out.

[Izento]

Ah. Yeah, I don't think I have enough mods (especially bigger turbo) for me to run irids, cause like you said, it seems like it runs rich with those, so in turn, your engine needs to be hotter in order to spark those well.

[TheMAN]

yup, platinum works fine
but like I said.. iridium is a very hard metal and also has greater resistance than nickel or platinum... it takes higher voltages to arc them
they work fine if you have either huge coils (CAs don't), or if you gapped them closer, which is a good thing to do if you're running more boost than stock anyway, to prevent the spark from "blowing out"... my van came with platinum plugs, but I upgraded to iridium plugs (OEM approved) and they work fine... big coil, and disty setup... not COPs like the CA has I upgraded because of longer service life, not for any performance reasons.... the plugs are a PITA to change out in my van, that's why

with weaker coils, they work fine when gapped closer, at .028 to .032, which is what the spec is for the Mazdaspeed Miata (it comes with iridum plugs, but normal miatas don't... tiny coils like the CA)
the Mazdaspeed Protege OTOH comes with platinum plugs and those are gapped to .042, using the same coils as the Miata

I mentioned these cars because they are fairly recent port injected turbocharged vehicles and of engine size and power output comparable to the CA18DET
other recent turbocharged vehicles have much higher power, bigger engines or other major differences that makes it harder to compare

[float_6969]

Mazdaspeed Protege plug gap spec is the same as the Mazdaspeed Miata, .028-.032. They'll break up at .042 while in boost with any mods in my experience (my DD is a Mazdaspeed Protege). Also, I thought the Mazdaspeed Miata had 4 coils mounted at the back of the head? The Mazdaspeed Protege has 2 coils mounted on the valve cover and runs wasted spark.

[TheMAN]

the miata has waste fire COPs just like the protege... they use the same coils, but different boots/wires in fact... the 2000 and earlier miatas have 2 coil packs mounted at the back of the engine next to the firewall, with 4 wires running off of it... that's what you were thinking about I believe

the owner's manual addendum for the mazdaspeed protege has that gap spec, but it's a misprint... if you buy the exact plug for the car from the dealer, it's gapped to .042... but if you buy plugs specific to the mazdaspeed miata at the dealer, they are denso iridium plugs gapped to .032 (the protege uses NGKs)... the 2003 shop manual which shows the mazdaspeed specific stuff also shows a .042 gap spec... the shop manual was published months later than that owner's manual too! that car always ran fine on platinum plugs at .042 at higher boost, but not so with iridiums... I can attest to that...

[float_6969]

I am thinking of the pre 2k miata. My wife has a '96 and I knew it had 4 coils, LOL!

That's interesting and might explain the issues I had. The original plugs fouled and needed replaced and I got some NGK coppers and threw them in @ .042 and they would break up. I gapped them down to .030 and they've been fine ever since. I still have downpipe and high flow cat to do and then I'm gonna turn up the boost to 10psi. If I have spark issues again, I'll try the platinums.

[TheMAN]

the regular protege uses shorter reach copper plugs than the mazdaspeed (platinums), effectively reducing timing... if you put in the wrong plugs (regardless of heat range or material), it could explain why
the coppers works fine as long as you changed them every 10k... basically 2 oil changes... waste of time, effort, money, and the environment IMO
platinum or iridium plugs give much better peace of mind and consistent performance for basically the same money given the miles you get out of each copper plug you changed for those same miles

I would not turn up the boost beyond 9psi on the protege without a J&S safeguard and some sort of basic fuel management system... the stock ECU sucks badly at detecting faint (but very damaging) knocking well and the response algorithms are slow as well as limited timing reduction.... also, without upgrading the "elbow pipe" (in nissan speak), you're still restricting the exhaust... it either needs to be outright replaced, or ported out to gasket match the outlet end (basically 35% larger)... anyway, different car, different subject, off topic

[float_6969]

Good info. When it's time to replace the coppers, I'll put platinums back in.

I'm on Mazda's 24/7, and have read a lot about the MSP. First thing I did was a SSAFC with supermap. It helped alot, but I was still hearing detonation (I have an ear for it for some reason, nobody else could hear it). So I got a CAI, it helped, but didn't fix it. Then I built a custom liquid to air intercooler setup and it's never detonated since. This is all at stock boost. As for the elbow pipe, sitting behind me, I have one of Pope's last 3" S/J pipe's. That's why I haven't turned up the boost yet either. Right now I'm having an issue with high oil consumption, so I'm trying to get that sorted out before I do any more power mods. I'm pretty sure it's bad valve stem seals. I'm waiting for some special tools I ordered to come in so I can replace them and see if it fixes it. If not, it's time for a new center section.

Meh, it's the CA section. We can offtopic all we want. If the OP doesn't like it, I'll delete all of our convo, LOL.

[TheMAN]

oil consumption is an ugly beast with that mazda engine.... it's due to a poor PCV system design as the engine was originally meant for N/A use... mazda didn't spend any money redesigning the valve cover for turbo use... as the engine wears or crap builds up in the piston rings, that exacerbates the blow by problem... valve seals maybe an issue, but I seriously doubt it's the major contributing factor in those engines... reducing oil consumption is no easy feat, but several measures can be done to reduce it... 1) switch to a thicker/better motor oil (dual gas/diesel rated helps), 2) do an engine flush to clean the ring packs... you can do it the slow gentle way or fast and hard if you're confident your engine has been well maintained/clean (use BG Quickclean), 3) use the Millenia S/929 PCV valve... only the OEM Mazda one would do, parts store ones are just disgusting CRAP... 4) modify the valve cover by stuffing the baffles full of stainless steel pot scrubbers or use an elaborate catch can/oil separator setup

anyway, you still need to get a J&S safeguard if you want to keep a stock motor together at higher boost, TRUST ME

[Izento]

Alright, as for getting off topic, I think it's interesting to hear about other motors. But also, I have heard that doing an engine flush is a bad idea because it removes valuable oil on the internals. I remember watching a video with Tsuchiya and the Lead Honda Engineer or president or s***, and he was saying that engine flushes should never be done. Just my 2 cents.

[TheMAN]

removes what valuable oil? you're cleaning out crap that oil normally can't get out, in a well maintained engine
then you drain it out after 10 minutes and put new oil in... if you're worried about that stuff still in there, change the oil again!

flushing is only a bad idea if the engine's history is unknown and definitively poorly maintained
in such cases, you just want to use a detergent heavy oil instead, changing often, and hope it cleans it up enough to use a gentle slow flush like AutoRX

[Izento]

removes what valuable oil? you're cleaning out crap that oil normally can't get out, in a well maintained engine
then you drain it out after 10 minutes and put new oil in... if you're worried about that stuff still in there, change the oil again!

flushing is only a bad idea if the engine's history is unknown and definitively poorly maintained
in such cases, you just want to use a detergent heavy oil instead, changing often, and hope it cleans it up enough to use a gentle slow flush like AutoRX

Check out this video, at 17:40 they start talking about what I was saying. I was off on what he was saying, but at least I remembered the ending message, lol. Btw, this guy is the president of Spoon, Tatsuru Ichishima.

http://www.youtube.com/watch?feature=pl ... lk#t=1062s

[TheMAN]

best motoring said it, it must be true

[Izento]

I try to at least listen to intelligent people, in the hopes I'll get there someday too, lmao.