The oem plugs are matched to the specific requirements of the stock FA20 engine. Whether or not the plugs are colder or hotter than other plugs used in other engines is irrelevant. The important thing is that the increased combustion chamber temps caused by FI require a colder plug to compensate.

I'm using stock plugs

Im using oem plugs too


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Anyone having any detonation issues with the factory plugs yet?

I don't think we will see anyone having issues with the stock plugs on most FI setups, other than changing gap requirements.

The stock plugs are about as cold as you can get from NGK or Denso.

No issues except when I burnt one from leaning out due fuel delivery issue.

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Need help.

Ive been advised to use one colder plugs for SC

Now investigating some are saying stock is 7 heat and some are saying 9 heat.
im looking at NGK plugs been advised to use these R2558A
Now do i use 8 heat or 10 heat

please help

i don't think you need colder spark plugs from what i had research.

maybe the best can chime in @Sportsguy83 @King Tut @Ironsquid @jamesm

Solely depends on what PSI SC Pulley you have on. Normally in a lower compression motor, you don't go with colder plugs unless you're increasing VE to a point that 1 step colder plug will still ignite fuel but reduces knock chance.

That aside, I don't think I've heard anyone on the Turbo kits running colder plugs yet. I honestly don't think it's needed for street use. My recommendation is factory plugs. If your tuner is advising colder plugs because you are knocking a lot, I would maybe get a second opinion from another tuner.

@FullBlown what range plugs are you guys using on that 700+ hp project

Edit: I have a hard time answering this. My knowledge from lower compression turbo applications is telling me that 1 step colder plugs could be worth it and not cause much issue. Have to remember we're dealing with a new territory. If it was my car I would wait for others with proven track history to mention the effects of colder plugs on this application. I know I've seen people make huge power without pushing timing to the point you need colder plugs.

I know nothing about spark plugs...but logically thinking about it, a colder setup I think will only be needed if your under consultant heated situations, like say at the track or drag strip or building a @FullBlown project. In *most* street applications the combustion temps are not high enough to warrent the switch to colder plugs. Even if someone is pushing ridiculous power, 500+ it's usually on E85 which has significant knock resistance in itself.

So is there a consensus on whether they are the equivalent of an NGK 9 or an NGK 7? NGK 7 is not uncommon on turbo engines for a stock plug--iirc the Evo 4B11T engine has a 7. 9 is very cold, and is only stock plugs on rotary engines (trailing plug) or engines that are not for passenger car applications (small engines).

I would stick with the OEM plugs. If you are having issues, then pull them out and check the gaps. If you are blowing out the spark, then close the gap up a little and put them back in.

i'm on oem plugs. just gapped down a bit.

What kind of boost/power are you making? I had a short discussion about this but the consensus was "fuck it". :D

hell i don't know, don't really care. i'm a drivability guy. the car makes more power than i can use. i have maps for 9.5, 11, 12.5, and 14 psi. it'll roast the tires on a 2-3 shift on dry pavement, if that means anything. i usually just drive around on the 9.5psi map.

last time it was on a dyno it made 259whp on a mustang @ ~8.5psi. going to a dynojet for some tuning monday, maybe i'll throw it up on a higher boost map then.