Personal spark plug experience

[meekerMS3]

My MS3 is getting its 50% ethanol tune next week. I just wanted to see if anyone can give updates on their experiences/preference of spark plugs? An extensive search mainly yielded sporadic results from the HPFP librication and flow issues thread.

I have a set of 1 step colder NGKs that I’m now pretty convinced I shouldn’t use.

Seems the best E mix option plug is the Denso ITV20? I’m curious to hear if people agree with this?

[Thor Hammer]

50% Ethanol? Hope you did your homework on black death.

Stock heat range is fine.

[Carskick]

Originally Posted by Thor Hammer 50% Ethanol? Hope you did your homework on black death. Stock heat range is fine.

I wonder if he means E50, or mixing 50% 93oct and 50% E85, which ends up at somewhere between E30 and E48 depending on the true contents of the E85. (Around here, the E85 is rated at at least 51% ethanol, the bastards)

I thought the general consensus was keeping under 50% ethanol significantly reduced the chance of black death, assuming no major oil leaks.

I am interested in the spark plug question. I'm using stock Heat Level Iridiums, and will be moving to an Ethanol blend soon, somewhere around E35-E45 or so. Justin with Freektune didn't seem to think cooler plugs were necessary for my application, so I'm sticking with these ATM.

[meekerMS3]

Originally Posted by Thor Hammer 50% Ethanol? Hope you did your homework on black death. Stock heat range is fine.

Yes ~50% e (first post edited to reflect that), and Yes I have done a lot of research, the spark plug preference is what’s least defined and why I asked.

Yep, black death prevention was one of the first things I researched.

[meekerMS3]

Originally Posted by Carskick I wonder if he means E50, or mixing 50% 93oct and 50% E85, which ends up at somewhere between E30 and E48 depending on the true contents of the E85. (Around here, the E85 is rated at at least 51% ethanol, the bastards) I thought the general consensus was keeping under 50% ethanol significantly reduced the chance of black death, assuming no major oil leaks. I am interested in the spark plug question. I'm using stock Heat Level Iridiums, and will be moving to an Ethanol blend soon, somewhere around E35-E45 or so. Justin with Freektune didn't seem to think cooler plugs were necessary for my application, so I'm sticking with these ATM.

My apologies, should have been more specific will be aiming for an ethanol/93oct mix that puts me around e48/49 or so. Those running a lower mix (~30%) were usually fine with one step colder. The grey area seems to be the 50% mix; from what I’ve read here it seems people have better luck though in the stock heat range. I was just hoping to get personal confirmation of that.

Yep below 50 helps, as well as RP dexos and the SI-1 fix


Agreed, from the posts I could find about plugs, it seems people running 100% e have to stay at stock heat range or possibly warmer. Those running

[Thor Hammer]

Oh ok, cool. You know what you're getting into with the higher E blend.

I would talk to your tuner about their recommendations on heat range.

[meekerMS3]

Originally Posted by Thor Hammer Oh ok, cool. You know what you're getting into with the higher E blend. I would talk to your tuner about their recommendations on heat range.

He should be getting off the dyno soon so I will shoot him a message, I just feel like these cars have a mind of their own. I come from the Wrx/STI world, and running step colder plugs was just common practice on pump gas and ethanol tunes (without issue either). The newer wrx’s were also DI.

[Carskick]

Originally Posted by meekerMS3 He should be getting off the dyno soon so I will shoot him a message, I just feel like these cars have a mind of their own. I come from the Wrx/STI world, and running step colder plugs was just common practice on pump gas and ethanol tunes (without issue either). The newer wrx’s were also DI.

A lot of people do run cooler plugs with these engines, especially when BT. I've seen a lot of people complain about them fouling up over time, but I have no personal experience with this. In other words, I've only used stock temp plugs.

From what I understand, running an Ethanol blend cools the combustion chamber more so than a purer gas mix. Wouldn't this negate the need for cooler plugs, at least to a point?

[meekerMS3]

Originally Posted by Carskick A lot of people do run cooler plugs with these engines, especially when BT. I've seen a lot of people complain about them fouling up over time, but I have no personal experience with this. In other words, I've only used stock temp plugs. From what I understand, running an Ethanol blend cools the combustion chamber more so than a purer gas mix. Wouldn't this negate the need for cooler plugs, at least to a point?

Yep, one step colder plugs are pretty standard once mods/power increases start happening. Frequent plug changes also becomes normal (15-20k). I think what starts to get us into the grey area is ethanol use and the fact these are DI engines.

Colder plugs help combat preignition, ethanol combustion temps are lower compared to just pump gas (so I think what you said makes sense, hopefully one of the ethanol kings here will lend their knowledge). It seems the temp drops created by the ethanol, and cold weather (which is now upon us) have given a lot of guys running a 50% ethanol blend issues with cold starts and surging, or just overall weird/poor running symptoms.

So hopefully someone who has first hand experience will help us out!

[meekerMS3]

Well, my tuner said either works but he would lean towards one step colder...so do I use the set of one step colder NGKs or my stock heat range Denso’s?

Guess I will just flip a coin...

[MoMS3]

One step colder will be fine, I have been running mine (NGK 6510) from stage 2 pump tune, all the way to stage 3 E30 tune. I just changed mine out around 15k and they weren't fouled, if you like to drive the car hard, just go colder as it will add a margin of safety.

Added ethanol like in your case might make the colder plugs not 100% necessary, worst case scenario they foul and you buy new plugs, not exactly hard to change plugs on our cars.

[meekerMS3]

Originally Posted by MoMS3 One step colder will be fine, I have been running mine (NGK 6510) from stage 2 pump tune, all the way to stage 3 E30 tune. I just changed mine out around 15k and they weren't fouled, if you like to drive the car hard, just go colder as it will add a margin of safety. Added ethanol like in your case might make the colder plugs not 100% necessary, worst case scenario they foul and you buy new plugs, not exactly hard to change plugs on our cars.

Thanks for the response! So the highest you have gone on the NGK 6510 is e30 correct? I may try them and then just switch to the Denso itv20s if needed. True, pretty easy on these cars.

[Thor Hammer]

This thread inspired me to do my own research to learn more on your question. This is an interesting read about ethanol:

https://www.6speedonline.com/forums/...-analysis.html

The end result is cylinder temps are 4.4% higher on ethanol. And since a colder plug removes more heat from the cylinder this makes sense to run a colder plug on ethanol blend tunes with bolt ons.

From NGK's website:

When compression is raised, along with the added power comes added heat. Since spark plugs must remove heat and a modified engine makes more heat, the spark plug must remove more heat. A colder heat range spark plug must be selected and plug gaps should be adjusted smaller to ensure proper ignitability in this denser air-fuel mixture.

Typically, for every 75-100 hp you add, you should go one step colder on the spark plug's heat range. A hotter heat range is not usually recommended except when severe oil or fuel fouling is occurring.

[5doorsoffury]

I have always ran stock heat range. Right now i have ngk iridium stock heat range with my mods on a 1:2 mix e:pump. I guess thats e 27? My plugs look great. Before that i was the same mix + meth on the stock turbo and they were fouling slightly. I wouldnt change your gap if it is fine now unless you start getting spark blowout.

[meekerMS3]

Originally Posted by Thor Hammer This thread inspired me to do my own research to learn more on your question. This is an interesting read about ethanol: https://www.6speedonline.com/forums/...-analysis.html The end result is cylinder temps are 4.4% higher on ethanol. And since a colder plug removes more heat from the cylinder this makes sense to run a colder plug on ethanol blend tunes with bolt ons. From NGK's website: When compression is raised, along with the added power comes added heat. Since spark plugs must remove heat and a modified engine makes more heat, the spark plug must remove more heat. A colder heat range spark plug must be selected and plug gaps should be adjusted smaller to ensure proper ignitability in this denser air-fuel mixture. Typically, for every 75-100 hp you add, you should go one step colder on the spark plug's heat range. A hotter heat range is not usually recommended except when severe oil or fuel fouling is occurring.

Thank you so much for researching this as well and finding that thread! Definitely an interesting ready! I think at this point I am going to try the one step colder NGKs, if I happen to get blow out or fouling then worst case I will just swap in stock heat range plugs.