Denso Iridium IK24 GAP: TTs and NAs

[ProwlerGT]

After searching around it seems pretty unanimous that the IK24's are your best bet for most of us TT or NA. I posted this in the general section cause I want to hear from the TT guys/gals too and hopefully their opinion stretches into the NA realm. I can't find ANYTHING on what gap the IK24's should be for the NA let alone for the NA ATX. I've read that some TT people with a certain degree of mods should gap it lower in the .029 - .035 range perhaps to avoid spark blowout, but what of this for the NA? At the same time the Denso web site (although I couldn't find the IK24 page specifically and just looked up 3000GT) says NOT to gap the plugs cause their design will take care of the gap needed. Aside from this there is proper "torque" of the plugs when you are installing them and I didn't know this when I installed mine about 1000 miles ago and I'm sure I put them in as tight as I could which was more than likely too tight.

Me having an NA ATX I of course want to make the best of my setup that I can. I have a rich condition going on and I only say that from smelling the exhaust (can't stand the smell; have to step away from it). My mods are BigTyla's ground wires, Apexi Power Intake cone filter and ebay BOMZ pipe, Rebuilt TB bored 3mm out to 63mm, MSD 8.5mm wires, and the plugs mentioned. I have it gapped at .042 and I swear it doesn't pull as hard in the mid-high range as it did with the previous Champion plugs that a shop installed. Funny enough though again the Denso site claims that the plugs they show for the 3000GT come gapped at .044 (think those were listed as IK20's) and not to change the gap cause their design is supposed to help make up for any changes needed.

So if there isn't a mod list that determines the gap for these IK24's for you TT guys, then what do you (or anyone else) think the gap for the IK24's should be for the NA? Is it the same gap that it'd be for the TT?

EDIT: FYI if it matters: Service manual stock plug gap using NGK PFR6J-11 or NIPPON DENS0 PK20PR-P11 plugs is: 1.0-1.1 mm (.039-.043 in.) with installation torque of 15 ft lbs

[97redvr4]

i think that the standerd gap is .42 and you want to gap them down to around .29-.35 to avoid spark blowout.
i have mine gaped down to .35 and no issues here.
i would also double check what the gap on your plugs are before you put them in. .44 seems to high of a gap for me.i would run .40 if had a na.
also, why run iridium plugs.why not use copper, they are much cheaper and provide the same spark as the iridiums would.

[gearheadvr4]

With copper you have to change them more often. But that could be a good thing since spark plugs can be used as an indication of engine health.

[VR4's-Kick-Ass]

I wouldn't tighten them so much. The heads are aluminum and you could damage the threads. There is some rule of thumb out there, I think it is tighten the plug then go a turn, but I am not 100% sure.

Also, I would use coppers. If you have spark blow out gap them down to around .30. Coppers are pretty cheap, and spark plug changes aren't too bad. Really.

[Black_Sunshine]

if u have a cat on there and are still able to smell unburned fuel, u have some major issues. i didn't see u list a test pipe. if ur smelling that much of it, pull the plugs and see if they're fouled already. the computer is seeing more air than the engine is actually sucking in. it's pumping in more fuel than is necessary, so somewhere in your setup, there's an abnormality causing the computer to richen your a/f mixture.

oh yeah, for me, i tighten them down until i can't hand tighten anymore, then stick on the socket wrench and turn it 1/4.

[ProwlerGT]

Originally Posted by 97redvr4

i think that the standerd gap is .42 and you want to gap them down to around .29-.35 to avoid spark blowout.
i have mine gaped down to .35 and no issues here.
i would also double check what the gap on your plugs are before you put them in. .44 seems to high of a gap for me.i would run .40 if had a na.
also, why run iridium plugs.why not use copper, they are much cheaper and provide the same spark as the iridiums would.

I put in the IK24's after reading they were pretty much the best choice for spark and longevity. Would the copper's last as long as the Iridiums in my NA then?

[vr4operator]

I absolutely LOVEED my Iridium's!!!! I have copper while breaking in the new motor, but as soon as i can afford it, Iridiums are back in. Slightly better power (in head maybe?) but def better gas milage. Consistently go at least 450 miles on the highway (lots o trips from Conn to Virginia) before light came on. I had to gap mine to .31 as i tried the 'stock' gap and had terrible blowout under high boost. So, rather than screw around, I set it to .31 and it was great. All stock ignition system except Accel 8.5mm wires...

[ProwlerGT]

Originally Posted by VR4's-Kick-Ass

I wouldn't tighten them so much. The heads are aluminum and you could damage the threads. There is some rule of thumb out there, I think it is tighten the plug then go a turn, but I am not 100% sure.

Also, I would use coppers. If you have spark blow out gap them down to around .30. Coppers are pretty cheap, and spark plug changes aren't too bad. Really.

Yeah actually I read on the Denso site (http://www.densoiridium.com/installationguide.php): "Using your fingers, screw the spark plug into the cylinder head, and tighten about 1/4-1/2 turn with a plug wrench. (Taper seat plug: about 1/16 turn)"

I'm only stating the install torque in this thread cause its good to note and I know I put mine in too tight although I was in careful form when I tightened them.

Honestly I'd rather change my plugs as least often as possible so I'll probably stick with the Iridiums. I'm not getting any younger and seemingly not any thinner. LOL - Spark plug changes are a bit of a hassle (to me) just like any other work on these cars.

How would I know if I have spark blowout? Whats a tell tale sign?

[ProwlerGT]

Originally Posted by 97redvr4

i think that the standerd gap is .42 and you want to gap them down to around .29-.35 to avoid spark blowout.
i have mine gaped down to .35 and no issues here.
i would also double check what the gap on your plugs are before you put them in. .44 seems to high of a gap for me.i would run .40 if had a na.
also, why run iridium plugs.why not use copper, they are much cheaper and provide the same spark as the iridiums would.

Whats the logic that leads you to gapping to a .040 in if you had an NA?
I HATE how everyone always leaves out the ZERO of the TENTHS position behind the decimal !!! AAAAHHHHHH ! LOL - Obviously when I gapped my plugs at .042 all I knew about spark plugs was that the larger the gap the more spark = more power, but this isn't necessarily true after I read from the BIBLE on stealth316.

[Black_Sunshine]

Originally Posted by ProwlerGT

I put in the IK24's after reading they were pretty much the best choice for spark and longevity. Would the copper's last as long as the Iridiums in my NA then?

the ik24's are meant for turbo cars because they are 2 steps colder than stock. this helps to keep knock to a minimum. the reason you might be having problems is because ur engine isn't producing enough heat for the spark plug to work properly. i would suggest switching out to ik20's.

this is from stealth316

Heat Range
Spark plugs are designed to work with the insulator tip and center electrode temperature within the ideal heat range of about 500ºC to about 850ºC (~930ºF to ~1560ºF). If the plug tip temperature exceeds about 1050ºC (~1920ºF), the air-fuel mixture in the combustion chamber tends to pre-ignite before a spark is produced. If the temperature is less than about 400ºC (~750ºF), the insulator tip and center electrode tend to foul with carbon and oil deposits, which can cause misfires, lowered available spark voltage, and poor driveability.

http://stealth316.com/2-sparkplugtech.htm