spark plug gap for NA motor lightly modded with SOS coils

[Joe88xj]

Hi guys I have a question about spark plug gap with aftermarket coils. I read that the benefit of aftermarket coils like the SOS coils (40k volts) vs stock 25k I believe is that the spark is stronger and therefore you can widen the spark plug gap and get a better burn and as a result a performance gain. I have brisk racing silver plugs and SOS COP coils. I have hi flo cats and x pipe and mufflers and plans for long tubes with cats deleted and a cam not sure which yet, I know the gain from this mod is small but I got the stuff new and cheap so I am adding them, cant hurt. Anybody out there with experience widening the spark plug gap for this reason?? I have read various gap settings for plugs from .028-.032 to .044 to .055. I read somewhere that the gap on these plugs with these coils can be set at .065 which seems ridiculous.
Please advise??
Joe

 

[stkjock]

Stock gap

stock coils proven best

BTW! Gaps are in thousands not tenths

 

[Joe88xj]

Stock gap

stock coils proven best

BTW! Gaps are in thousands not tenths

LOL...fixed it!

 

[Five Oh Brian]

NA, I've had best luck with aftermarket coils with spark plug gaps around .040." Good blend of smooth idle/cruise and power. Supercharged and WOT, .050" to .055" has worked well for me. All in all, there is very minimal gain with an aftermarket coil NA. I do, however, really like them with the higher cylinder pressures of forced induction to minimize/eliminate spark blow out.

 

[fourdegrees11]

NA, I've had best luck with aftermarket coils with spark plug gaps around .040." Good blend of smooth idle/cruise and power. Supercharged and WOT, .050" to .055" has worked well for me. All in all, there is very minimal gain with an aftermarket coil NA. I do, however, really like them with the higher cylinder pressures of forced induction to minimize/eliminate spark blow out.

Are you running aftermarket coils on your current car? I cant recall seeing that in your monster thread. I think it would be pretty cool to see you log the 1/4 mile difference (if any) with aftermarket coils if you havent already?

 

[Juice]

+1 for .040". I put in a set of iridium "performance upgrade" as per the product description. They come gapped to .040. No issues. But I'm 99%stock. Only mods are CAI and high flow catted X, and straight through mufflers.

I always found engines like slightly closing the gap on plugs, definitely gap to the tight side of the spec.

 

[Pentalab]

Manual for my 2010 auto sez 1.5mm or .060 inches....that's for NA. With my 5.8 psi boost, I use .035 inches. If 8-9 psi used, then gap is down to .032 inches. Even with 8-9 psi boost, one step colder plugs are not required. That's per VMP. I currently use Brisk plugs + .035 gap. B4 small M90 blower installed, it was .060 + oem ford plugs. I noticed that with the brisk plugs and .035 gap, that the misfires on the aeroforce gauges, dropped to zero.

 

[Five Oh Brian]

Are you running aftermarket coils on your current car? I cant recall seeing that in your monster thread. I think it would be pretty cool to see you log the 1/4 mile difference (if any) with aftermarket coils if you havent already?

I installed aftermarket coils in my '14 GT in early 2016 and still have them in the car. They have worked flawlessly and the car does idle smoother. I have back-to-back data from the dragstrip with & without them on two days that were identical weather with the same Density Altitude. I chose not to include them in my monster thread for 2 simple reasons:

1) too many people get bent out of shape around here if you use anything other than a stock OEM coil and I didn't want to hear the negativity, and

2) the performance improvement was repeatable & consistent, but so small that I figured nobody would care one bit (.03 second and .15 mph in the 1/4 mile). That improvement equates to just a one (1) horsepower increase!

In retrospect, the aftermarket coils were not worth the money, in my opinion. Over $500 for a 65,000 volt set! There are many other mods that yield much more bang-for-the-buck in our cars. I'll run them until they fail, then reinstall the factory OEM coils.

Probably the best thing that came out of this was that I pulled all of my spark plugs and gapped them identically and found the gap that my car liked best. The gaps from the factory varied a bit, and I'm OCD about things being consistent and even!

 

[fourdegrees11]

Wow, awesome feedback!

 

[stkjock]

1) too many people get bent out of shape around here if you use anything other than a stock OEM coil and I didn't want to hear the negativity, and

I wonder if the difference from the aftermarket 3V to the Coyote coils narrowed. with the 3Vs and the older 5.4 4Vs the stock coils clearly were proven better. I haven't really kept up with the Coyote mods as closely as I did the 3Vs.

 

[Five Oh Brian]

I wonder if the difference from the aftermarket 3V to the Coyote coils narrowed. with the 3Vs and the older 5.4 4Vs the stock coils clearly were proven better. I haven't really kept up with the Coyote mods as closely as I did the 3Vs.

Well, I can't conclusively say that the OEM Coyote coils are any better than the aftermarket coils - either in terms of power or reliability. Time will tell in my car.

With my 3V, I had 2 aftermarket coils fail in the first year. I've had the aftermarket coils in my Coyote for 1.5 years with zero issues.

I work at a Ford dealership and occasionally here customers in our service department talk about failed OEM coils, so I suppose any coil-on-plug can fail.

 

[stkjock]

I wasn't so much talking about longevity, more about ability to make power, it seemed the stock coils were more reliable as well, and big power was made with them. My shelby made 960 whp on a DynoJet with stock coils

 

[01yellerCobra]

I ran Accels in an older 4V. WOT was great. Idle sucked and part throttle went both ways. Went back to a stock set and never had another issue.

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[skaarlaj]

I'd just do what the manual says. I doubt a dyno would show anything up to the point of too much gap and spark blowout because of it.

I used to run an 03 Lightning with the plugs gapped at .035", I added nitrous and immediately had spark blowout, so I went down to .025" and it ran the same exact times when not using nitrous with the smaller gap. So my theory has since been to run as much gap as possible without experiencing blowout, but on a lightly modded NA engine, I'd just go with the manual's spec.

 

[46addict]

What does spark blowout feel like? Is it like a misfire? Or can it only be seen in a datalog?

 

[skaarlaj]

I ran Accels in an older 4V. WOT was great. Idle sucked and part throttle went both ways. Went back to a stock set and never had another issue.

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I'm running MSD's on our old 2001 supercharged 4wd supercrew F150 because one of the originals finally gave up, and a set of 2V MSD coils from Summit was much cheaper than OEM. They've been fine so far, and no change in performance that I could tell with about 3 years / 10-15K miles since swapping.

 

[skaarlaj]

What does spark blowout feel like? Is it like a misfire? Or can it only be seen in a datalog?

This truck, while using nitrous before tightening the gap would sort of sputter, or have intermittent mis-fires when full throttle under boost. It was a very obvious feeling, but aside from using nitrous, like idling, cruising, or even getting on it hard without nitrous it would run just fine / smooth. A datalog might show some erratic O2 sensor readings, and on these newer cars, you may get a misfire code, but I've never had a condition like this with my Coyote, probably a much better designed combustion chamber from the 4v's architecture vs. our old 2V lightning, and probably a stronger ignition system as well?

 

[01yellerCobra]

I'm running MSD's on our old 2001 supercharged 4wd supercrew F150 because one of the originals finally gave up, and a set of 2V MSD coils from Summit was much cheaper than OEM. They've been fine so far, and no change in performance that I could tell with about 3 years / 10-15K miles since swapping.

I think this is one of those mods where it's hit or miss. Unfortunately for me it was a miss and I've heard about enough misses to keep me using the stockers.

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[skaarlaj]

I think this is one of those mods where it's hit or miss. Unfortunately for me it was a miss and I've heard about enough misses to keep me using the stockers.

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I've lucked out, and have never had to address ignition systems on many of the vehicles I've owned over the years, but lots of stock ignition systems have ran really good for me in boosted, NA, and nitrous applications all with factory ignition systems aside from tighter plug gaps in non NA applications. I personally leave ignition components alone until a problem arises.