Spark Plugs

[Tooltime19]

Its that time again. Time for some spark plugs amongst other things.
What the consensus about the NGK Iridium spark plugs over the factory OEM copper plugs. I purchased, the NGK p/n LFR6AIX-11 plugs. Have not installed them yet.
1-Are they worth the cost?
2-Will I see or feel any performance gains?
3-Will MPG's go up?
4-What is the best plug for the money for any performance mpg's ect.
Im the avid and "spirited" on and off road driver type, so any bolt on stuff is appreciated.
Thanks in advance.
:cheers:

 

[ebg18t]

I installed the iridiums not for 'performance' but for ease of maintainace since they last a lot longer.

 

[OrdnanceMarine]

Its that time again. Time for some spark plugs amongst other things.
What the consensus about the NGK Iridium spark plugs over the factory OEM copper plugs. I purchased, the NGK p/n LFR6AIX-11 plugs. Have not installed them yet.
1-Are they worth the cost?
2-Will I see or feel any performance gains?
3-Will MPG's go up?
4-What is the best plug for the money for any performance mpg's ect.
Im the avid and "spirited" on and off road driver type, so any bolt on stuff is appreciated.
Thanks in advance.
:cheers:

1-Yes
2-Probably not
3-Not enough to notice with usual methods of measuring
4-Get the NGK or Denso long life models

There's a reason that every modern Toyota and Honda engine I've dealt with comes with these plugs from the factory now. They offer a slight improvement in performance, probably largely due to the fact that the electrode can be so tiny so there is less "shadow" inside the cylinder as the flame front spreads since there's less metal in the road of the flame kernel.

Main noticable advantage of these over copper is the service life. I've got other things to do besides change out copper plugs every 30k miles. I forget but I think the iridium long life models from NGK and Denso are good for 100k.

Bottom line: Get 'em and use 'em! They're really good.

 

[Ask10]

From the factory mine had Iridiums.

You wont get more hp or a "cleaner burn" whichever rubbish auto part stores will feed you, but if all is working well on your truck, they will last 3-4 times longer. I've seen Iridiums go 150k miles before but coppers would be hard pressed to make it 40-50k.

If you go copper you will just replace plugs sooner, but if you try Iridiums in a "copper system", sometimes the ignition system can't cope with firing the Iridium plugs and you get misfires.

 

[chitown40]

If you have the V8, then go with a platinum plug or OEM equivalent.

If you have the V6, use plain old Toyota copper OEM plugs (Denso). They're cheap, easy to find, and are what came on the truck from the factory. They can be had for about $2/ea.

 

[NOVA46]

1-Are they worth the cost? Yes
2-Will I see or feel any performance gains? Slightly better acceleration, more complete combustion
3-Will MPG's go up? - No or barely
4-What is the best plug for the money for any performance mpg's ect.
Im the avid and "spirited" on and off road driver type, so any bolt on stuff is appreciated. - NGK Laser Irigium
Thanks in advance.
:cheers:

my 7 cents

 

[OrdnanceMarine]

If you have the V8, then go with a platinum plug or OEM equivalent.

If you have the V6, use plain old Toyota copper OEM plugs (Denso). They're cheap, easy to find, and are what came on the truck from the factory. They can be had for about $2/ea.

The only reason platinum plugs were ever used were for longevity. Iridium plugs "bought back" the lost performance that platinum plugs saw when many makers changed from copper plugs to platinum. If you're using platinum plugs and it's time to replace them, go with iridium.

Also, if you have the factory copper plugs on your V6 (probably very few or they are way past due to be changed) you may find that you had NGKs on one bank and Denso plugs on the other bank. Toyota used both as OEM suppliers and one is as good as the other so I'd shop on price. Others have mentioned this over the years and that's what I found when I replaced mine in the ~40k mile range.

 

[MikeInNH]

1-Are they worth the cost?

It's a personal choice.

2-Will I see or feel any performance gains?

Absolutely NOT.

3-Will MPG's go up?

Absolutely NOT.

Iridium or Platinum plugs were designed to last longer...PERIOD. They do NOT give you better performance or better gas mileage. Copper is a far better conductor then Platinum or Iridium. Copper will actually outperform the other plugs. The problem is you have to change them more often.

On the 4runner it's no big deal. Takes me less then an hour to replace all 6 plugs. But my wifes Lexus - I use Iridium plugs. Those back 3 plugs are a royal pain to replace.

Show me ONE professional race car that doesn't user Copper plugs. If Iridium or Platinum plugs gave them a .01% advantage they'd all be using them...and they're NOT.

 

[OrdnanceMarine]

Show me ONE professional race car that doesn't user Copper plugs. If Iridium or Platinum plugs gave them a .01% advantage they'd all be using them...and they're NOT.

I'm not sure you can borrow from the racing world and say that because something is or isn't used in the racing world it therefore is or isn't better for the street/trail world. You wouldn't ever make that argument regarding motor oil, would you? True racing motor oil employed in situations other than racing can yield disappointing results since passenger car motor oil is designed to deal with acid buildup over long periods of time while racing oil is largely designed for shear stability under high heat.

That being said, yes copper is a better conductor than platinum or iridium but I think you're referring to electrical conductivity which is essentially meaningless for these applications. The kind of conductivity racing engines are looking for is thermal conductivity; the ability to remove heat from the plug at a high enough rate to prevent pre-ignition in an engine that is run at 100% load far longer duty cycles than a passenger car application. A quick internet check shows the thermal conductivity of copper to be about 400 units (we won't worry about what units for now since we'll use the same unit) while copper is 147 and platinum is 70. I also believe that in race applications you end up messing with the plug gaps on a regular basis to tune for a specific set of conditions and you cannot reasonably mess with the gap of an iridium or platinum plug. These two factors (thermal conductivity and gapping) are what I thought the real reason that race applications tend to stick with copper plugs. Please correct me if I am wrong.

 

[MikeInNH]

Yes..thermal conductivity is an issue...but you can use a colder or hotter spark plug to get the conductivity you want.

At high RPM's (10,000)...you don't want your spark plug missing even ONCE for a 300+ mile race. That's the reason I understand all race drivers use copper.

Don't get me wrong..I like Iridium plugs.

 

[guardsred944s]

Oh Boy...

Dude...
http://www.toyota-4runner.org/3rd-gen-t4rs/165014-e3-spark-plugs-review-stories.html
http://www.toyota-4runner.org/4th-gen-t4rs/164656-factory-spark-plugs.html
http://www.toyota-4runner.org/4th-gen-t4rs/163348-75k-spark-plugs-replaced.html
http://www.toyota-4runner.org/4th-gen-t4rs/161787-2003-limited-v8-spark-plugs.html
http://www.toyota-4runner.org/4th-gen-t4rs/161787-2003-limited-v8-spark-plugs.html

For the record I picked up the stock Denso's from my local dealership on Friday and they seem to be working VERY well. They told me "DO NOT GAP THESE YOU WILL MESS THEM UP". Okay I won't gap them, JEEZ! I did not gap them, they work fine.

As to the science discussion happening up here^:

The material used in creating a spark plug, or any conductor, has conductivity (or it's practical inverse resistivity). It's like density but for electrical materials. For practical purposes, copper has as near as makes no difference, perfect conductivity. In fact, only one material (silver), possesses a higher conductivity than copper(both being in purest available forms).

What creates the spark, in a gasoline engine, is not the metal but the air in between. When the breakdown voltage of the air in the gap is met or exceeded, permittivity* is achieved, effectively making the air a conductor. This breakdown voltage will depend on:
1) The size of the gap (distance through air to travel through)
2) The chemical makeup of the air (okay so there is atomized fuel in there too, as well as some other remnants of combustion).
3) If something is blocking the gap, the chemical makeup of that substance will have a conductivity that needs to be considered as well.

Spark plugs can be a great litmus test of an engines health, they very rarely fowl themselves. Fowling will decrease or more likely increase the breakdown voltage thus (albeit VERY marginally, I say negligibly) retarding your ignition.

Fowling is caused by the stuff in your engine, which is determined by your ECU, fuel, and the design. So use the plugs that are specified in your manual!!!!

I believe that the use of the Platinum/Iridium comes from those materials' strong resistance to corrosion, and thus a reluctance to variance in gap size. But why even bother thinking about this when you can just change them with stock every 30 or 40k!

I wanted to put in cobalt plugs, but some guy named Doc. Brown used them to travel into the future (or past?).

:deadhorse:

*ehh, its been awhile... V= shutup

 

[ebg18t]

My v6 and I think all the v6's came from the factory with the iridium plugs, 3 Denso and 3 Ngk. By installing fresh iridium plugs your just keeping things as-is. Many of us drive Toyotas since they are low maintenance and just work.

 

[toyo]

The only reason platinum plugs were ever used were for longevity. Iridium plugs "bought back" the lost performance that platinum plugs saw when many makers changed from copper plugs to platinum. If you're using platinum plugs and it's time to replace them, go with iridium.

Also, if you have the factory copper plugs on your V6 (probably very few or they are way past due to be changed) you may find that you had NGKs on one bank and Denso plugs on the other bank. Toyota used both as OEM suppliers and one is as good as the other so I'd shop on price. Others have mentioned this over the years and that's what I found when I replaced mine in the ~40k mile range.

This is spot on. I remember back in the late 80's working at Toyota we so many wild myths on why Toyota used different plugs. It's crazy they use both brands but Toyota knows what they are doing.

My 2013 Tacoma had both as well. Personally I have always preferred Denso plugs. Why? I guess it's a Toyota thing...

I tell people all the time that if you keep your vehicle properly maintained you should not really be able to tell the difference when you change out plugs, etc. Unless of course one or two plugs have actually crapped out earlier for other reasons such as too much blow by in a cylinder or tube seals leaking.

 

[NOVA46]

Just wanted to recommend this:

Swivel spark plug socket

It acts as a swiveling 6" extention and has a magnet to hold the spark plug, keeps it from getting damaged, and eliminates the fear of cross-threading. It worked beautifully. And here are the spark plugs I ordered:

NGK Laser Iridium

 

[toyo]

Good job NOVA46. One thing I like to do is put a little of my trusted Seafoam on the threads and screw it in by hand. Goes in like butter. Makes me feel better!

 

[MikeInNH]

I guess if you pay someone to change your plugs...then the Iridium plugs might be a good choice since you're paying for labor.

But I like to change my plugs...easy to do on the V6 4runner. And one nice thing about when you change them...the plugs will give a good indication of how well the engine is running. So that's another reason to use Copper plugs.

 

[OrdnanceMarine]

My v6 and I think all the v6's came from the factory with the iridium plugs, 3 Denso and 3 Ngk. By installing fresh iridium plugs your just keeping things as-is. Many of us drive Toyotas since they are low maintenance and just work.

As best as I'm aware, they came with copper plugs. 3 Denso and 3 NGK were in my rig as well. I hadn't seen a copper plug used in a vehicle I had changed the plugs in since my '98 Civic. It brought a little nostalgic tear to my eye! Only way makers could meet the "100k miles with no tune ups" was to switch to a more erosion resistant material and that had been platinum. Early iridium plugs couldn't make it 100k miles.

Again, longevity was the reason for platinum and iridium. If you are the kind of guy who's going to pull plugs every 20-30k miles anyway just because you like to (whether to eyeball the health of the engine, which isn't nearly the issue it was back in the day, or just because you like to connect with your engine on that level) then copper is probably a better choice since they are a fraction of the cost and you get a fresh plug to install. If you want to "fire and forget" and not worry for another 100k miles, go with the long life iridium.

 

[MikeInNH]

If you want to "fire and forget" and not worry for another 100k miles, go with the long life iridium.

The other thing you have to worry about with 100k mile plugs...is removing them after they've been in there for 100k miles. Some people have had issues with stripped threads.

 

[Tooltime19]

Thanks for all the excellent replies. Typically when it comes to OEM ignition and electronic operating systems throughout todays vehicles, I tend to stick with the OEM p/n's. And this is mainly due to there not really being any further performance gains without going in a playing with the computer, which in my case will never happen. At my first plug change at 30k, I too had the split NGK/DENSO combo.
I don't remember which unit of the two I used at 60k. For chits and giggles, I thought I would toss the question of plugs out there for the masses in case someone found something that works well.
Thanks again for all the responses. And like someone mentioned above, I am one of those guys who likes to keep up on and know what the motor/drivetrain ect is trying to tell me. By spending extra time pre and post trip, looking closely at everything in and under all my rigs helps keep my stuff safe and sound. I fall into that percent of heavy users, but not an abuser, which calls for more and closer inspections. My neighbors think Im crazy because between my three vehicles, its seems like Im always in my garage. But hmmm, who do they always call when their vehicle goes down. lol

:cheers:

 

[BCfish]

The other thing you have to worry about with 100k mile plugs...is removing them after they've been in there for 100k miles. Some people have had issues with stripped threads.

Nothing a little anti-seize wouldn't stop. I always put a little on my plugs and any other fastener that may seize up.