Changing Spark Plugs

[Pablo Pistoffo]

ITS THE PLUGS. I'VE WENT BACK TO STOCK MULTIPULE TIMES FOR THIS EXSACT REASON. ANYTIME AFTER DRIVING AND IT ABOUT 5-10 MINUTES OF BEING PARKED IT DOES CRANK LONG. CHANGED THE PLUGS TO FACTORY AND NO PROBLEM. BUT AS OF NOW IM TUNED WITH DIZZY SO I HAVE TO RUN THE PLUGS

I had occasional issues with step colder plugs on my Dizzy tune last winter when I was running step colder NGKs. This summer I switched to the pre-gapped Brisks that Ron has, haven't noticed any issues. It's hard to give the car a good run up here to keep them burnt off when it is cold and the roads are ice rinks, but so far so good.

 

[SteveS]

What is the obsession with step colder spark plugs? Plugs are just plugs. The heat ranges don't make more power, which seems to be the belief in modern tuner circles. The heat range is for proper matching to the cylinder conditions. If plugs run too hot and you get predetonation or you see evidence on a plug check they are running hot, THEN you should run colder plugs. If the plugs are fouling, you run hotter plugs.

If you have a tune and the OEM heat range plug shows that it is working well, just use the OEM heat range. Going to colder heat range will result in more trouble.

 

[Pablo Pistoffo]

What is the obsession with step colder spark plugs? Plugs are just plugs. The heat ranges don't make more power, which seems to be the belief in modern tuner circles. The heat range is for proper matching to the cylinder conditions. If plugs run too hot and you get predetonation or you see evidence on a plug check they are running hot, THEN you should run colder plugs. If the plugs are fouling, you run hotter plugs.

If you have a tune and the OEM heat range plug shows that it is working well, just use the OEM heat range. Going to colder heat range will result in more trouble.

My understanding is that step colder plug would allow higher boost levels before the system detects knock and reduces boost. Ever since SAAB's APC, systems like this have allowed for more power based on conditions, rather than keeping a lower safe level across the board. For me, I need as much help as I can get when I'm engaging in parking lot battles with "real" sports cars, so it's worth the hassle. YMMV, and there is something to be said for simple and reliable.

 

[LionsTooth]

I would also add that if you can feel the oh-so-minor difference on a one-step colder plug (other than the starting issues), you should be test-driving for Rahal Lannigan Letterman.

 

[Ford ST]

My understanding is that step colder plug would allow higher boost levels before the system detects knock and reduces boost. Ever since SAAB's APC, systems like this have allowed for more power based on conditions, rather than keeping a lower safe level across the board. For me, I need as much help as I can get when I'm engaging in parking lot battles with "real" sports cars, so it's worth the hassle. YMMV, and there is something to be said for simple and reliable.

Bingo you nailed it.


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[FiestaSTdude]

If you're going iridium, you want the NGK 6509 (or 6510- one-step colder) plugs with a gap of .025.

O'Reillys and auto zone say the NGK iridium 6509 plugs don't fit the FiST. Can someone confirm that they fit or it that the wrong part number?

 

[FiestaSTdude]

Also, thank you for the explanation of why someone would run colder plugs. I personally am just going to run the stock plugs because I'm more concerned about reliability.

 

[SteveS]

My understanding is that step colder plug would allow higher boost levels before the system detects knock and reduces boost. Ever since SAAB's APC, systems like this have allowed for more power based on conditions, rather than keeping a lower safe level across the board. For me, I need as much help as I can get when I'm engaging in parking lot battles with "real" sports cars, so it's worth the hassle. YMMV, and there is something to be said for simple and reliable.

That's true. But if your car has trouble starting, or if you need to "clear out the plugs" by revving the engine, your plugs are too cold. If the tuner cannot make a tune which encompasses proper fuel mixture and ignition throughout the rev range and in all conditions, it's not a proper tune. You cannot really call a tune right if you have to switch spark plugs for normal driving and more spirited driving. If plugs are fouling, the plug is too cold or the mixture too rich. If you're getting predetonation, the mixture is too lean, the ignition too advanced, or the plug is too hot. That's really all there is to it.

But the way people talk about plug heat ranges it's as if they believe that the colder plug is always better and it makes more power. Yet the things they are having trouble with indicate that the plugs are too cold, and they'd be better off with the original heat range plug.

 

[Pablo Pistoffo]

That's true. But if your car has trouble starting, or if you need to "clear out the plugs" by revving the engine, your plugs are too cold. If the tuner cannot make a tune which encompasses proper fuel mixture and ignition throughout the rev range and in all conditions, it's not a proper tune. You cannot really call a tune right if you have to switch spark plugs for normal driving and more spirited driving. If plugs are fouling, the plug is too cold or the mixture too rich. If you're getting predetonation, the mixture is too lean, the ignition too advanced, or the plug is too hot. That's really all there is to it.

But the way people talk about plug heat ranges it's as if they believe that the colder plug is always better and it makes more power. Yet the things they are having trouble with indicate that the plugs are too cold, and they'd be better off with the original heat range plug.

That's a good point. I was a little frustrated with the occasional stumble during the winter, but the Brisks seem to have cleared up the issue, at least in my car.

 

[M-Sport fan]

Yeah, if a tuner cannot write a tune for me using the factory heat range plugs (OR the given fuel brand I MUST use!), even with the consequence of slightly less peak power (which also might have the benefit of helping extend the whole power/drive train's longevity), then I guess I will not ever get a tune.

 

[Ford ST]

The Genesis G70 I have colder spark plugs are basically mandatory if you want to add any power. The gap also needs to be changed. What happens if you don't do this on those vehicles well you're probably gonna blow a spark plug.

I have ran colder spark plugs in previous vehicles and never had a problem. I also don't drive like a grandma with a handicap sticker. Foot to the floor all day everyday.




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[Sam4]

O'Reillys and auto zone say the NGK iridium 6509 plugs don't fit the FiST. Can someone confirm that they fit or it that the wrong part number?

Sorry. If O'reilly and autozone say something - that's it, game over. 6509's are in my car for 20 thou miles.

 

[TyphoonFiST]

The only reason most of the time they say something is the Rattle head behind the counter doesn't know how to look into the Comments or details file to compare thread pitch to the OEM plug as it usually says not applicable to this vehicle or non- OEM style plug. I've usually had to just say....Just do what I ask and let me worry about the details.

 

[FiestaSTdude]

Sorry. If O'reilly and autozone say something - that's it, game over. 6509's are in my car for 20 thou miles.

Thanks!

 

[FiestaSTdude]

Just changed the plugs today (finally!) and that spark plug socket is super helpful! Now I have nice new NGK 6509s gapped at .025.
One of my plugs had a little bit of oil on the top, maybe a leaking valve cover gasket (at least that's what causes in on the mk1 focuses). Not enough to worry me at the moment.
I still need to see if this fixed the issue I was having though.

 

[FiestaSTdude]

Also, thank you for the explanation of why someone would run colder plugs. I personally am just going to run the stock plugs because I'm more concerned about reliability.

Ok, I may have lied. I'm getting a Dizzy tune and he recommends one step colder plugs. Should I switch mine to 6510s?
At least if I do it again, I'll know how thanks to all the helpful replies I got

 

[LiLfieSTa]

Ok, I may have lied. I'm getting a Dizzy tune and he recommends one step colder plugs. Should I switch mine to 6510s?
At least if I do it again, I'll know how thanks to all the helpful replies I got

id say you do what he recommends. (NGK Iridium 6510)
im currently running dizzy with step colders as well gapped at .028 (recommended by dizzy) but mine are Brisk not NGK and its been super solid for me.

The only stuttering i get is the known issue with after fill-ups, but i hardly care about that since its rare for me.

 

[Business6]

ITS THE PLUGS. I'VE WENT BACK TO STOCK MULTIPULE TIMES FOR THIS EXSACT REASON. ANYTIME AFTER DRIVING AND IT ABOUT 5-10 MINUTES OF BEING PARKED IT DOES CRANK LONG. CHANGED THE PLUGS TO FACTORY AND NO PROBLEM. BUT AS OF NOW IM TUNED WITH DIZZY SO I HAVE TO RUN THE PLUGS

I've exactly the same issue. Once the car gets warm good luck getting it started again. That was with a tune for 1 step colder, too. This has happened with different brand plugs from different sources and the same exact problem.

 

[Intuit]

That's true. But if your car has trouble starting, or if you need to "clear out the plugs" by revving the engine, your plugs are too cold. If the tuner cannot make a tune which encompasses proper fuel mixture and ignition throughout the rev range and in all conditions, it's not a proper tune. You cannot really call a tune right if you have to switch spark plugs for normal driving and more spirited driving. If plugs are fouling, the plug is too cold or the mixture too rich. If you're getting predetonation, the mixture is too lean, the ignition too advanced, or the plug is too hot. That's really all there is to it.

But the way people talk about plug heat ranges it's as if they believe that the colder plug is always better and it makes more power. Yet the things they are having trouble with indicate that the plugs are too cold, and they'd be better off with the original heat range plug.

Couldn't agree more. Might find it interesting that on a different engine (no oxygen sensor for self-tuning) had to enrich to keep from fouling the plugs. I never thought I'd have to enrich to keep a set of plugs from fowling. Added an AFR gauge so I had some visibility into my tweaking the mixture. Have some other interesting tid-bits but will keep it short due to being a tad off-topic.

 

[FiestaSTdude]

I just bought 6510s from Whoosh, so now I have both
I'm going to go with the 6510s with the tune because that's what Dizzy recommends and I trust him to know what he's talking about. If I have issues with starting, I'll still have the (basically new) 6509s.