Denso IK22 spark plugs after 30K miles of Supercharged driving

I honestly wasn't expecting this:





The one on the left is from the driver side bank, and the one on the right is from the passenger side bank. All 3 from each bank look the same....with the exception of the center electrode wasn't COMPLETELY gone on one of the driver side plugs....just almost gone.

I suppose this is why they specify dual electrode plugs for this spark application. Obviously all the electrode material always goes the same direction on each bank...you can see the "pile" of metal on the passenger side plug that is missing from the top. And all the metal from the center electrode on the driver side is just gone.

Are all you supercharged folks changing these ridiculously expensive IK22's every 15k miles??

Isn't 30k the recommended replacement cycle

So kind of makes sense they are worn a bit

BrianSD_42 said:

Isn't 30k the recommended replacement cycle

So kind of makes sense they are worn a bit

Click to expand...

Yeah, but when I replace spark plugs at the recommended interval, I assume them to still be fully funtional. The drivers side bank that has no center electrode left.....I don't consider that to be functional. They're nominal at best. lol. IMO, if you go 50K between changes, you should expect what I'm seeing, but not just 30k.

I think I may go back with some dual electrode plugs that are still a heat range colder.

Are you running lean?

A dual electrode to me is for a tight flat combustion chamber, where in with two gaps available the spark is going to happen where the highest concentration of fuel molecules are.

You are using the wrong plug type almost have to use the twin tip plugs on the 5vz. Did you go stock heat range or a step colder? You need to run a step colder, 91 or better fuel at the least with a supercharger on these motors. The plug with the really worn electrode looks to have been getting hotter than the other one. I would be looking at a lean condition or predetonation in that cylinder. Are you running more fuel, 7th injector?

Left one looks like the cyl is running lean, the white is from heat, right one looks a little rich, but rich is safer.

Guys, in order for what you're saying about rich and lean to be true, the entire bank would have to be that way. This is not a case of lean and rich...it never runs lean. IK22's are two heat ranges colder than stock. I always run 93 octane. It's not detonating. They have been the recommended plug for supercharged applications for a while, even though they are not dual electrode. The issue is the ignition system on the 5vz-fe: the driver side bank of cylinders, the spark flows from the center electrode up to the top, taking the iridium with it little by little on every spark. On the passenger bank the spark always flows from top to the center electrode, hence the missing metal on the top electrode and the pile of extra buildup all around the iridium center.


Until seeing these plugs, I didn't realize how hard this ignition system was on single electrode plugs. Iridium's are even supposed to be way more resistant to this happening than say, platinum or copper plugs, because the Iridium ions "stay in place" better. I imagine a single electrode platinum plug would lose its entire center electrode on the driver side within 10-12k miles.

Any other supercharged giys running IK22's see this same thing? I'm really wondering if you simply change them more often.

Yep mine did the exact same thing. i think had about 35k miles on my set of IK22's

If you look at a plug from the passenger side back, you will see that the ground electrode is more worn than one from the driver side bank.

The waste spark system that the 5VZ uses means that the direction that the spark travels is opposite between banks. Thats why the driver side positive electrode is worn and the passenger side ground electrode is worn

Edit: Here are some posts from my build thread about this
http://www.toyota-4runner.org/3rd-gen-t4rs/65520-turbo-rock-lobster-10.html#post1463566

http://www.toyota-4runner.org/3rd-gen-t4rs/65520-turbo-rock-lobster-10.html#post1488788

Edit again: I'm dumb and didn't read your whole post. You caught the whole mumbo jumbo about the ground electrode already. I'm gonna go hide under a rock now.

I have the NGK version of your plug in my 3.4L and after the wreck I swaped them over to the 97's engine.........I have no clue how many miles are on them. I know they have many miles on them though. the engine had 265,000 miles and from the rest of the maintenance done to it I'm betting its only the second set of plugs in it. But look nothing worn like yours....And my gaps were all at .043

The ground arm being purple all the way to the threads isn't right to me. it should stop half way around the bend. also my ceramic is a nice light brown color not shades of black like yours.

Its not supercharged like yours but those plugs don't look like normal ware to me even if its supercharged.

The O2 sensor is not monitoring single cylinder parameters but a average of all three cylinders in its respective bank.....so if one cylinder is running lean from a poor flowing injector all it knows is that the exhaust comming out of that head is leaner than expected and richens up all three injectors to compensate.......Thats why its important to have clean injectors and if sent out for cleaning, getting 6 back that are flow matched....With a supercharger its even more important.

If I had a boroscope I'd be looking into the cylinder of the plug with the electrode melted off and make sure the piston doesn't have a melt spot.

Running a supercharger I'd wan a AF monitor in the exhaust to make sure the fuel curves are correct. I have a hard time seeing a stock PCM being able to accuratly compensate for the extra airflow and HP the supercharger provides.

Driving down the road what are your LTFT's for sensor 1 on both banks?

Edit.....looks like you are looking at the AF ratio.

quicksilvr said:

Guys, in order for what you're saying about rich and lean to be true, the entire bank would have to be that way. This is not a case of lean and rich...it never runs lean. IK22's are two heat ranges colder than stock. I always run 93 octane. It's not detonating. They have been the recommended plug for supercharged applications for a while, even though they are not dual electrode. The issue is the ignition system on the 5vz-fe: the driver side bank of cylinders, the spark flows from the center electrode up to the top, taking the iridium with it little by little on every spark. On the passenger bank the spark always flows from top to the center electrode, hence the missing metal on the top electrode and the pile of extra buildup all around the iridium center.


Until seeing these plugs, I didn't realize how hard this ignition system was on single electrode plugs. Iridium's are even supposed to be way more resistant to this happening than say, platinum or copper plugs, because the Iridium ions "stay in place" better. I imagine a single electrode platinum plug would lose its entire center electrode on the driver side within 10-12k miles.

Any other supercharged giys running IK22's see this same thing? I'm really wondering if you simply change them more often.

Click to expand...

What were the plugs gapped at?

Plugs were gapped at .035 when they were installed. I think the plugs look bad (dark, extra carbon buildup) because I drove it for a couple weeks with it running bad with the CEL on and the ignition timing fully retarded. I'm going to check each piston with a scope before I put it all back together.

I also think I will take 19963.4lsr5's advise and send all the injectors to Witchhunter and have them cleaned and flowmatched.

quicksilvr said:

Plugs were gapped at .035 when they were installed. I think the plugs look bad (dark, extra carbon buildup) because I drove it for a couple weeks with it running bad with the CEL on and the ignition timing fully retarded. I'm going to check each piston with a scope before I put it all back together.



I also think I will take 19963.4lsr5's advise and send all the injectors to Witchhunter and have them cleaned and flowmatched.

Click to expand...

At least you gapped them tighter. I saw a bunch of posts saying the supercharger gets the same spark gap. I think that's a no no. You could tighten it to .028 also.

What was your CEL?

Actually the whole reason I'm working on the truck right now is the CEL. It was P0330, knock sensor. So I'm doing TB, water pump valve covers and the knock sensors now. Along with spark plugs. And the fuel injectors.

How did the other two driver's side plugs look?

I ran some single electrode platinum NGK plugs back in 08 for about 10,000 miles (non S/C). The 5vz wasn't happy with me.

I know on YT that one member had looked into buying an NGK colder plug that was from Europe, and not offered here in the states. He was running a S/C as well, and going through plugs quickly. I don't know what ever was the outcome.

[MENTION=40945]quicksilvr[/MENTION], so are you just going to write this off as part of the Supercharged life on the 3rd gen?

Are there any dual electrode plugs that are also cool enough?

LittleCaesar said:

How did the other two driver's side plugs look?

I ran some single electrode platinum NGK plugs back in 08 for about 10,000 miles (non S/C). The 5vz wasn't happy with me.

I know on YT that one member had looked into buying an NGK colder plug that was from Europe, and not offered here in the states. He was running a S/C as well, and going through plugs quickly. I don't know what ever was the outcome.

Click to expand...

2 of the 3 driver side plugs were identical. The 3rd still had a little tiny bit of center electrode left sticking up....it was the middle of the 3 in the drivers side bank.

amalik said:

[MENTION=40945]quicksilvr[/MENTION], so are you just going to write this off as part of the Supercharged life on the 3rd gen?

Are there any dual electrode plugs that are also cool enough?

Click to expand...

Yes, I'm sure there are. I'm going to find some now actually....

Ok, the factory heat range for Denso plugs is designated by the number 16. Larger the number, the colder the plug (for Denso...and most spark plug brands)

Follow this link to see a nice chart of spark plug heat range designations: DENSO SPARK PLUGS


22's are two steps colder. 20's are one step colder.

I think I may switch to just one step colder than stock. Which means for a Denso plug I need dual electrode 20. For NGK, the number is 6. For Champion, its 10 or 9, and for Bosch it's 7 or 6. Confused yet?


I'm going to get either Denso K20TR11's or K22TR11's. Give them a try and see how it goes.

How is your knock sensor harness? It goes under the intake doesn't it? If it does oil and heat equals brittle or broken wires.

Is your code clear yet?

I believe that toyota advises to not use the dual electrode spark plug when supercharged. I used to run those ngk iridiums and never had any trouble on my supercharged tacoma (5vz).

Do you have any fuel mod? Are you experiencing excessive detonation?

Edit, i just checked the install documentation for the supercharger and didnt actually see anything about spark plugs so i dont know where i got that but it sure seems like people used to say to stay away from dual electrode plugs. Either way having a colder plug is the important part.