Spark Plug Gapping Preference for Turbo Build
 

Before I get started, I just wanted to say I've already done my fare share of studying before coming down to actually typing this question out for the past hour or two to no avail - so sorry in advanced if there has already been a definite answer.

It's been a mixture of inconstant answers as to what the best measured gap is for the OEM spark plugs in a turbo charge application.

Build:
2015 FR-S changing spark plugs @ 68k (yes I know its a bit over due lol)
Speed By Design SBD500X turbo that gets around 10PSI max on boost.
Stock injectors with DW300C upgrade fuel pump tuned by Delicious.
Daily Driven - spirited driving - no track.
Bogged a bit once turbo's under boost at around 4k but never got down to the problem as it just went away over time?

So nothing too crazy with the build, pretty average for a turbo set up at best. I've read a mixture of either going colder on a different set of plugs, which I just ended up purchasing the OEM set since they were pretty ideal.

Some say .032" pregapped and leave it at that, while some others are vowing to tighten it due to possibility of blow out and ranges the measurements from .020 like the WRX, .022, .026, .031, etc.

Trying to not waste any more of your time but what gapping have you guys got good results with on a normal set up? Thanks again in advance for any question and I apoligize if this has been over asked since I haven't found a good thread.

Depends, on a few things

You want the biggest gap your ignition system can support.

The bigger the gap, the bigger the spark, the bigger the spark the bigger the flame front, the bigger the flame front the better the burn, hence, more power.

I'm running stock 0.8mm (0.032 "ish") running 8 psi with stock ignition, I have no issues.

I needed to run 0.6 mm (0.023") on my RB running 25 psi with upgraded splitfire coils.

IMO, first point of call would be to check your coils and wiring before touching your plugs.

Unless your plugs are over 50 k, iridium plugs can last longer, but they do lose efficiency over time.

I'm currently running oem plugs with stock .032 gap. Running 20psi without any issues. Will be going up before next spring to around 28 psi at which point I may need to revisit this myself.
In my opinion, at your levels, even though you are higher compression than I am, I see no need for you to need to touch anything right now.

Unless you're having spark blowout, I wouldn't worry about it or change it. Good thinking though

Okay perfect, so for anyone currently looking up this same question, final consensus if you’re switching plugs on a turbo application, OEM is fine and stock .032” gap is fine for pretty average turbo set ups around 10 PSI and proven no problem to 20 psi on some. Thank you guys for your time in replying, really helped a lot, and I hope this thread helps people in the future.

@FRS Justin ...from what I can remember, he is running stock plugs and gap at 700hp.

What coils?

I have no idea.

Stock plugs and gap with stock coils.