Plugs/Gap - Modified LT4s
 

When I changed to this blower, I also changed to NGK 6510, w/.028 gap.

I'm wondering what others here have done for new plugs/gap?

I'm running Brisk RR14S @ 0.029 with a TVS2300 @ 14-15 psi

Not as modified as a lot of you, but running, as suggested by JRE, about .040" and around 15-16-psi. Running 1-step colder NGK Iridium for now. Might go down one more step to see how he likes it.

I also use the NGK 6510, gapped to 0.035 at 17psi boost.

I too am running the Brisk at 14-15 psi boost

Stock LT4 is 0.030, not sure why you'd go that much larger, in fact some brands wouldn't want you to open them up that far.

6510 NGK LTR7IX IRIDIUM

I agree and I wanted to see what others here are doing, I figured NGK would be popular and am not surprised about the range of gaps posted so far 0.028 - 0.040. Such larger gaps scare me.

Agreed.

.028- .031 is a great nominal range to run plugs on boosted applications due to the excess pressure that boost induces into cylinders. Any more than that and high boost levels equals spark blowout which would be bad news.

No, stock is 0.037 to 0.043

Denso ITV27 at their stock gap (~0.030). Good enough for 22 PSI from Mag 2650

I'm with Ted on this topic.
Good explanation in this video https://youtu.be/G_DiTh8gQ6w

Just like they taught us at mechanic school, your spark will be stronger with a larger gap. Because the Voltage is raising to jump the gap. But yes there is a point where your ignition system is maxed out, and the spark might not be able to jump the gap anymore with raised cylinder pressure. This is when you have to compensate the pressure by closing the gap. Ted said it well, you always benefit from running the max. POSSIBLE gap.

For example.
When I imported my ZL1 to Switzerland, after it just came from a performance shop in Florida it did not run well. Cutting out and stumbling. Lots of missfires, especially with every cold start.
Turned out they gapped the new plugs to 0.027.
Then I installed new plugs, gapped to 0.037 and it ran perfect after.

Now after more mods, and higher boost / cylinder pressure, I closed the gap to 0.035. This is also what alot of big name tuners recommended for my setup.

Not sure what boost you are planning to run, but if it is around 20psi I would say you are ok with that 0.029 gap.

My memory failed me on that one, the spec you have is correct for plug gap.

I do remember being on the dyno and having to gap them down to ~0.030" from ~0.040" or so once hitting around 15 psi on TVS2300. That's what it took to get the most power, timing, and no misfires to 7k rpm on my car. My car is running 93 with 50/50 water/meth (mostly for cooling and a little octane). It might be possible to go a little wider but not sure I'd find the benefit easily. I did find the Brisk plugs were much less prone to misfires, might be an opportunity to go wider and see.

I'm not sure what fueling everyone is using and if running E blends changes the game here with gap.

NGK 6510 gap to .022 for me