ScionDad

Well, last night while my daughter slept, I switched out the stock plugs with the Denso IK22 Iridium....a colder plug...

I figured rather than plant it in her head of any difference, I didn't say anything about it so I could see if she did notice anything.

She left for work this morning and called about an hour ago out of the blue.

She asked if I did something to her car. I said no, why, what's wrong (I thought something was really wrong)?

She said nothing was wrong, but it's the weirdest thing.

When I drove to work this morning, the car for some reason had quicker response when I push on the gas and felt like it ran stronger , even into boost. It idles better and I didn't even hear one backfire. It's the strangest thing. Is there anything that could have just broke in or something?

So, I started laughing and told her I did change the spark plugs. I just wanted to see if there was going to be any noticable difference and not telling you would be the only way to get that info without tainting it.

The stock iridiums I took out looked really good. It appears from them the AFR is just fine....I'll grab a few pics of one and post. They have about 2000 miles with the turbo on them.

PoizentC

Thanks for the info. I'm going to pick some up today. When switching to a colder plug for turbo, do you just go 1 step down or would more steps be more beneficial?

ScionDad

Yea, the Denso IK22 I believe is 1 step down. You could also go to the IK24 which has a bigger gap. But I heard that drops your fuel economy big time. Don't forget a little packet of anti sieze for the threads. Also, make 100% sure your car is dead cold. The difference in metal types and heat could cause a thread damage issue taking them out.

raamaudio

Glad you have had such good results, I tried one step colder Iridiums in my 13PSI Matrix and it just did not work. Then I tried Platinums, no better, was advised to go with copper, one step colder, had to order the right plugs, then it made a very significant improvement. Though the A/F was correct on the other plugs it would misfire fairly often at high RPMs.

Then again, that was at 13PSI;)

Rick

BrEaK_AwaY

glad to hear it worked out for ya man

DTRUONG_112

thanks for the info.

lo_bux_racer

That's consistent with what I've seen with Supras. They like iridium plugs a lot. One step colder should be all you need for street, but for a track day, I'd put in two steps colder.

I suspect you were getting timing retard with the hotter plugs, and now you are not. It would have been interesting to log EGT before and after.

apexjr

If I remember right I put the IK22's in my MR2, it runs 16psi and runs amazing. I think there is a lot of things that may make the plugs work well or not. Compression, AFR, Cams, shape of the cylinder.

Denso's are some good plugs, imo.

turbo2liter

Iridium's seem to work better with hot ignition's, but they are performing very well. A lot of guys are fouling them out after 3000 miles or so, so be prepared.

lo_bux_racer

If it's genuinely fouling, they're too cold. That's what the heat range is all about: keeping the porcelain clean. Too cold fouls, too hot detonates. Pretty simple fix.

Revilo

somebody can post a webpage where i can learn about spark plugs (gap, int and ext electrode, material, etc)

lo_bux_racer

Start here. You would be wise to read everything you can find on the NGK site, you'll be able to detect serious BS from a long distance when people are telling you about what changing a plug did.

Follow the basics with this and focus on the bits under the Plug Construction Features to Consider heading. Lots of helpful info there.

Revilo

maybe im wrong, but i dont see any link, or it didnt work...

lo_bux_racer

Fixed. Typing too fast. Sorry.

Revilo

thanks... one last question... the air/fuel mixture should be 50/50?

lo_bux_racer

Not for gasoline. Might be a tad on the rich side.

Sounds like you've got some more homework on the basics to do. Google is your friend.

Revilo

i need to learn more

Revilo

so, for a N/A tC, what air/fuel mixture should be use. [using Denso iridium spark plugs 0.8mm (hot spark plug) ]

DuMa

please adopt me.

bubblemyster

pictures. pictures. pictures.