NgkTr6 gap question

[John81]

Does .022 gap sound right for NGK tr6 plugs here's the info on my truck
02 lightning built short block
Walbro pumps w/ upgraded wiring , #60 injectors
Long tube headers, EGR delete
JLP intake, sct 2600 maf
8lb lower pulley, stock ported Eaton sc
Nx nitrous 100 shot w/standalone fuel C6 race fuel.

 

[4a7191a]

Someone will chime in. If not I'd refer to some of the terminators , since your running nitrous.

 

[Darren5.0L]

That gaps seems excessively small to me, it might be in your interest to open that up a little, what other gaps did you try and did you get spark blowout? Were it my truck I would experiment to see if the combination would run at 0.028" smoothly at WOT.

Further, how are the plugs looking at that heat range? I would personally expect something in the heat range 7 might be more appropriate for what you are running.

 

[John81]

It popped a bit at wot , I'm going to re gap at 0.028 and see how it works

 

[Dusten]

As stated, I would almost suggest a plug like a BR7EF for that setup, gapped around .028

 

[John81]

Forgot to mention I'm boosting 18 lbs .. thanks for the replies

 

[mizlplix]

18# and nitrous........wot pops....... #7 plugs gapped at .028".

But I'd seriously want to datalog to make sure the fuel delivery is OK,
and the timing.

Miz

 

[Dusten]

Forgot to mention I'm boosting 18 lbs .. thanks for the replies

What's the pulley combo? With stock heads, 18lbs is pretty easy because there is no flow

 

[Darren5.0L]

I have a 4lb lower and see boost creep at the very top of a pull to 17 psi, it happens.

I see he's got an 8lb lower so pulleys for 16-17 psi total?

To the OP, here's the thing, why do we close the gap on our plugs?

In a perfect world we would run the widest possible gap allowable to ignite the fuel/air mixture as quickly and efficiently as possible. The wider the gap (in theory) the bigger the spark kernel to light off the charge, quicker ignition, more complete combustion, more power.

However we are limited in the size of gaps mainly due to ignition "strength" and the conditions under which the spark must survive. If the gap is too large the spark will "blow out" so to speak and not ignite the charge properly leading to poor performance, misfiring, or outright loss of power.

Since the Lightning ignition system is pretty much of a fixed output, when the conditions in the combustion chamber become more unfavorable, through the addition of boost, for example we respond by tightening the gap to ensure a strong spark is able to arc between the electrode and the ground strap.

If we gap too small, we may give up performance, or suffer poor fuel/air charge ignition because the spark kernel is strong but too tiny to ignite the entire charge during the very narrow window of the combustion event.

Here are some reference spark gaps for talking points.

5.0L NA Windsor engine 0.054"

5.0L Windsor, or Modular engine with modest boost (<12 lbs) 0.035"

Modular with ~12-17 lbs, +/- 0.032"

Modular with 18+ lbs, +/- 0.028"

and so on, basically the goal is to run the largest possible gap that gives 100% ignition reliability, in this case Dusten and I are suggesting 0.028". This is basically what is known to work, we aren't just throwing dart at the wall.

The heat range of the plug has little to do with spark ignition and has everything to do with thermal extraction, which keeps your plug from suffering high speed glazing or worse yet, turning into a glow plug and causing pre-ignition.

To keep this from becoming the Encyclopedia Britannica of spark plugs

TR6's are about right for the 14 psi range, and I have run them on my GT500 to 19 psi briefly, however the almost certainly correct plug for 18 psi and above is the BR7EF that Dusten mentioned.

If the combination will not run at 0.028" on a BR7EF you should look at the whole system, ignition coils, your WOT AFR, it could be too rich or too lean, there are a lot of things to consider. The Ford COP system, when in good working condition is a pretty strong system.

0.022" is very tight, I could maybe see 0.026", maybe.

Does the truck pop at WOT on boost alone, or only when on the spray?

 

[John81]

I have a 4lb lower and see boost creep at the very top of a pull to 17 psi, it happens.

I see he's got an 8lb lower so pulleys for 16-17 psi total?

To the OP, here's the thing, why do we close the gap on our plugs?

In a perfect world we would run the widest possible gap allowable to ignite the fuel/air mixture as quickly and efficiently as possible. The wider the gap (in theory) the bigger the spark kernel to light off the charge, quicker ignition, more complete combustion, more power.

However we are limited in the size of gaps mainly due to ignition "strength" and the conditions under which the spark must survive. If the gap is too large the spark will "blow out" so to speak and not ignite the charge properly leading to poor performance, misfiring, or outright loss of power.

Since the Lightning ignition system is pretty much of a fixed output, when the conditions in the combustion chamber become more unfavorable, through the addition of boost, for example we respond by tightening the gap to ensure a strong spark is able to arc between the electrode and the ground strap.

If we gap too small, we may give up performance, or suffer poor fuel/air charge ignition because the spark kernel is strong but too tiny to ignite the entire charge during the very narrow window of the combustion event.

Here are some reference spark gaps for talking points.

5.0L NA Windsor engine 0.054"

5.0L Windsor, or Modular engine with modest boost (<12 lbs) 0.035"

Modular with ~12-17 lbs, +/- 0.032"

Modular with 18+ lbs, +/- 0.028"

and so on, basically the goal is to run the largest possible gap that gives 100% ignition reliability, in this case Dusten and I are suggesting 0.028". This is basically what is known to work, we aren't just throwing dart at the wall.

The heat range of the plug has little to do with spark ignition and has everything to do with thermal extraction, which keeps your plug from suffering high speed glazing or worse yet, turning into a glow plug and causing pre-ignition.

To keep this from becoming the Encyclopedia Britannica of spark plugs

TR6's are about right for the 14 psi range, and I have run them on my GT500 to 19 psi briefly, however the almost certainly correct plug for 18 psi and above is the BR7EF that Dusten mentioned.

If the combination will not run at 0.028" on a BR7EF you should look at the whole system, ignition coils, your WOT AFR, it could be too rich or too lean, there are a lot of things to consider. The Ford COP system, when in good working condition is a pretty strong system.

0.022" is very tight, I could maybe see 0.026", maybe.

Does the truck pop at WOT on boost alone, or only when on the spray?

Truck does some popping at Idle then when I decelerate there's some backfire, that might be bc I have no cats. I took my truck back to my tuner and he said I was lean at idle and that might be an air leak . As for the popping at Idle he said its the gap on the plugs and that I should do 0.030. The issue I was having in the beginning which I should have stated in the beginning was that my truck at Idle when I reved it up to about 3k rpm the rpm would drop fast and truck would die or right before I parked my truck it would also just die on me .. could this be a leak somewhere? Or spark plug gap?

 

[2003SVTFreak]

Br7ef, recessed tip and already come gapped .030 in the box.

Sent from my SAMSUNG-SM-G930A using the svtperformance.com mobile app

 

[LimpStimpy]

I don't remember who made this chart years ago, but a lot of people used to reference it as a starting point.