NA Spark Plugs

[Protege_Speed]

Thinking about switching out my plugs. I have searched around and I noticed that most of you recommend the NGK. Questions is, which one should I go with? I am thinking either the ZFR6FIX-11 or the ZFR7FIX-11. Or should I go with the 5 heat range since that is what the NGK part finder recommends? I do have a MPI so I am thinking I should go with a colder plug but how much colder.

 

[twilightprotege]

best to check what your current plugs are doing. are they reading hot or cold? then decide what heat range to get from there

 

[Maz2001MP]

even with the slightest mod (intake, exhaust), I would suggest getting a step colder. A 6 will probably be ok.

 

[protito]

ok call me the dummy but what would getting a colder plug do for a N/A application. i have heard of people getting them when they use nitrous to prevent detonation. is it the same reason?

 

[capnsavem]

ok call me the dummy but what would getting a colder plug do for a N/A application. i have heard of people getting them when they use nitrous to prevent detonation. is it the same reason?

yes, i also am dumb. please enlighten Protito and I, for we only know that proteges attract the honeys. the only reason why we bought 'em. am i right Protito? (alright)

 

[Maz2001MP]

yes they are used for detonation prevention. a 1 step colder plug plug couldn't hurt it at all. just make sure you hit redline once in a while to burn off the carbon deposits on the plug tip hehe..

 

[Maz2001MP]

Essentially they would be better for a higher compression NA engine/FI/Nitrous. Like twilight said check your plugs.

From what I see on the boards people who run 5's tend to say thier plugs run a little too hot, even when close to stock applications. That is why I suggested the 6's, it can't hurt and will run a little cooler.

The only problem is that the cooler plug doesn't allow carbon deposits to be burned off the tips as easily. That is why it would be good to hit redline once in a blue, to heat things up and clean out the plugs a little bit. Correct me if I'm wrong...

 

[flat_black]

Running cooler plugs would cause you to run a little richer, as well, as a warning. So if you're running rich now, best not to push it even further. =)

 

[tyusha]

OK i guess i am a moron. I am running denso iridiums and i have no idea how to find whether they are colder than stock or not...

 

[twilightprotege]

denso use a similar system. 16 = ngk 5, 20 = ngk 6, 22 = ngk 7...something pretty similar to that anyway.

so i assume you have the IKxx's - see above for heat ranges. 5 = hot

 

[Protege_Speed]

I don't think that will be a problem. Keeping myself from hitting redline is harder.

just make sure you hit redline once in a while to burn off the carbon deposits on the plug tip hehe..

 

[stdntDrvr]

hmm...i have the denso iridiums too...and my car runs rich as hell...is there a way (other than a FMS) to lean it out some?

 

[AznXstazy]

i run ngk v power, they run pretty rich... when i put them in the first week the tip was black a bit. now its still black a bit, after 2k miles i think. ya anyone know how to lean it out?

 

[Protege_Speed]

well, luckily I do have a piggyback to lean it out if need be.

 

[Maz2001MP]

I believe our cars run extremely rich regardless of what plugs we use. I think better engine management should solve that problem, and correct me if I'm wrong but one step colder plugs really shouldn't make all that much of a difference.

I don't think there is a need for aftermarket plugs unless you are going to go colder to prevent detonation, like I said before I have seen some threads where people complain that even thier 6 heat range was even almost coming close to running hot. I think the 5's are good for a totally stock application. If you are going to do some mild upgrades (full exhaust, intake, ECU, maybe some small bump in compression or mild cams) I would suggest looking into colder plugs.

 

[Maz2001MP]

I was actually going to run 7 heat range NGK coppers for my turbo setup (that's if I decide to go with the FI), but FI is a total different story. lol

 

[twilightprotege]

yeah my 6 heat range plugs are on the verge of running too hot. i've got a set of heat 7's at home waiting for microtech

 

[Gen1GT]

Running cooler plugs would cause you to run a little richer, as well, as a warning. So if you're running rich now, best not to push it even further. =)

Actually, running colder plugs inaccurately leads people to BELIEVE they're running rich, because plug deposits aren't getting burned off as easily. But plugs have nothing to do with how much fuel enters the combustion chamber.

High compression ratios actually create more heat than does turbocharging. ie, running 12:1 CR will create more heat than 15psi.

 

[flat_black]

Very true; On the intake mixture side of things, you aren't technically running richer. However, on the exhaust side of things, more fuel and carbon deposits exit, which is a good deal of the 'richness'... Reading your plugs is rather important to show you if you're too hot or too cold, though, and accordingly, will dictate the amount of time from spark to flash. Too tight of spark timing in conjunction with an early or excessivly quick ignition (too hot) can cause slight problems with detonation... Under the same principle, though, if the flash occours too slowly after the ignition, your burn will be slower, and less complete as you move to the exhaust stroke, forcing out a good deal of unburned fuel. This is also dictated by the octane rating of the fuel, the ACTUAL pre-ignited air to fuel ratio, combustion chamber shape and several other factors, but I think picking the proper plug is a good first step. Then polish and reshape your combustion chambers. I might be skipping a step in there, though. Hehe.

 

[mp3moose]

so should I be running colder plugs?