The "Correct" Plug for High Boost.

[Jaywebs]

The long and short of it is, I have been running NGK 6510 gapped to 0.028 in my gen 3 procharged making 19lbs at wot. Decided to freshen them up so I had ordered a new set. Started to second guess the gapping prior to installation so reached out to NGK tech. I was informed that the 6510 is yes, 1 heat range colder which I already knew, however is the wrong plug for my application. How you say??? Tech support states that 1 heat range colder on a FI car is only good up until 10psi. Any boost levels exceeding that can cause detonation. The correct plug for anyone making more than 10 lbs. but less than 20lbs. is R7448A-8 which is 2 heat ranges colder. Any of you guys making high boost, please chime in. Would love to see who is running what plugs at what gaps.

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[Cory S]

6510’s with a .023-.024” gap.

 

[Angrey]

The long and short of it is, I have been running NGK 6510 gapped to 0.028 in my gen 3 procharged making 19lbs at wot. Decided to freshen them up so I had ordered a new set. Started to second guess the gapping prior to installation so reached out to NGK tech. I was informed that the 6510 is yes, 1 heat range colder which I already knew, however is the wrong plug for my application. How you say??? Tech support states that 1 heat range colder on a FI car is only good up until 10psi. Any boost levels exceeding that can cause detonation. The correct plug for anyone making more than 10 lbs. but less than 20lbs. is R7448A-8 which is 2 heat ranges colder. Any of you guys making high boost, please chime in. Would love to see who is running what plugs at what gaps.

It's never smart to argue against the people that make the plugs, but there are plenty of people making big power on 6510's, in fact, MOST people running those plugs are running more than 10 lbs of boost.

The heat range is only one factor, what he's either discounting or not understanding is that the gap of the plug contributes to how hot it gets. A tiny gap (to guard against blowout) requires less voltage to spark and therefore adds less heat to the plug. Furthermore, nearly everyone uses E85 at higher power which burns colder (so 10 psi on an old school 93 setup with a big gap might be true).

The risks of running a plug too cold are that it doesn't burn hot enough to rid contaminants and eventually will foul the plug. Which is the lesser evil compared to a plug too hot, but this is one of those times when the empirical data from widespread tuners probably accounts for something the manufacturer isn't considering.

 

[Cory S]

It's never smart to argue against the people that make the plugs, but there are plenty of people making big power on 6510's, in fact, MOST people running those plugs are running more than 10 lbs of boost.

The heat range is only one factor, what he's either discounting or not understanding is that the gap of the plug contributes to how hot it gets. A tiny gap (to guard against blowout) requires less voltage to spark and therefore adds less heat to the plug. Furthermore, nearly everyone uses E85 at higher power which burns colder (so 10 psi on an old school 93 setup with a big gap might be true).

The risks of running a plug too cold are that it doesn't burn hot enough to rid contaminants and eventually will foul the plug. Which is the lesser evil compared to a plug too hot, but this is one of those times when the empirical data from widespread tuners probably accounts for something the manufacturer isn't considering.

100% nailed it.

 

[Jaywebs]

6510’s with a .023-.024” gap.

That's what I think a lot of guys are doing

It's never smart to argue against the people that make the plugs, but there are plenty of people making big power on 6510's, in fact, MOST people running those plugs are running more than 10 lbs of boost.

The heat range is only one factor, what he's either discounting or not understanding is that the gap of the plug contributes to how hot it gets. A tiny gap (to guard against blowout) requires less voltage to spark and therefore adds less heat to the plug. Furthermore, nearly everyone uses E85 at higher power which burns colder (so 10 psi on an old school 93 setup with a big gap might be true).

The risks of running a plug too cold are that it doesn't burn hot enough to rid contaminants and eventually will foul the plug. Which is the lesser evil compared to a plug too hot, but this is one of those times when the empirical data from widespread tuners probably accounts for something the manufacturer isn't considering.

Well written and a big thanks for clarification.

 

[80FoxCoupe]

The long and short of it is, I have been running NGK 6510 gapped to 0.028 in my gen 3 procharged making 19lbs at wot. Decided to freshen them up so I had ordered a new set. Started to second guess the gapping prior to installation so reached out to NGK tech. I was informed that the 6510 is yes, 1 heat range colder which I already knew, however is the wrong plug for my application. How you say??? Tech support states that 1 heat range colder on a FI car is only good up until 10psi. Any boost levels exceeding that can cause detonation. The correct plug for anyone making more than 10 lbs. but less than 20lbs. is R7448A-8 which is 2 heat ranges colder. Any of you guys making high boost, please chime in. Would love to see who is running what plugs at what gaps.

I run Brisk RR12S under 20psi at .020, RR10S over 20psi at .018.

 

[LethalPerformance]

I've used the 6510's in a few of my builds with great results. Project Goldmember was a Gen 3 with 3.0L Whipple at about 19psi. Car went 8.64@157 with the 6510's gapped .020-.022. My 2020 Shelby GT500 with 3.8L Whipple at 22psi went 8.86@163 with the same plugs and gap.
My latest project Cobro is my 03 Cobra which was coyote swapped with a Gen 3, 10R80 and Whipple 3.8L at 22psi. That car makes just around 1000rwhp now. I run the 6510's in that car as well gapped the same as the others.

The 6510's are good for about the 1000-1100rwhp range but have worked well in higher hp applications of mine. If you really intend on making more than 1100rwhp then the Brisk RR12S's are what I'd recommend.

Let us know if there's anything else we can help you with.

Thanks!

 

[SolarFlare]

Brisk RR12s here as well.

 

[Jackson1320]

It's never smart to argue against the people that make the plugs, but there are plenty of people making big power on 6510's, in fact, MOST people running those plugs are running more than 10 lbs of boost.

The heat range is only one factor, what he's either discounting or not understanding is that the gap of the plug contributes to how hot it gets. A tiny gap (to guard against blowout) requires less voltage to spark and therefore adds less heat to the plug. Furthermore, nearly everyone uses E85 at higher power which burns colder (so 10 psi on an old school 93 setup with a big gap might be true).

The risks of running a plug too cold are that it doesn't burn hot enough to rid contaminants and eventually will foul the plug. Which is the lesser evil compared to a plug too hot, but this is one of those times when the empirical data from widespread tuners probably accounts for something the manufacturer isn't considering.

this is not 100% accurate.
the heat range is the amount of heat a plug retains not how hot it sparks. a plug two heat ranges colder will still produce the same spark. the voltage doesn't determine how much heat a plug retains ether. heat range refers to the insulator. on e85 the combustion is not as hot so the plug doesn't get as hot as on 93 so you need a hotter plug to get to the optimal heat range here's some info

https://www.denso.com/global/en/pro...e-parts-and-accessories/plug/basic/heatrange/

 

[gimmie11s]

6510's are great plugs and my car runs perfect with them. Im trying ITV-24 Denso's now and it seems to run good with them also.

The 6510's are a protruded tip plug and the Denso's are not. Some people prefer the non-protruded tip in high HP applications.

 

[engineermike]

The explanation doesn’t make a lot of sense. Detonation occurs in the unburned mixture after spark. Once the spark happens the mixture closest to the plug combusts first so there is no time for detonation to occur at that location. The detonation usually occurs in the ring-land area (which is why ring lands break) because that is the last place to combust, so it experiences the highest pre-combustion temperature, pressure, and delay time. Detonation is a function of octane, pressure, temperature, and time.

If he had said pre-ignition, it would make more sense.

 

[markmurfie]

With modern fuel control keeping cars running at stoich the requiement for the plugs to clean them selfs by getting to a certain temperature is much less frequent. Most cars are coming with cold or very cold plugs already from OEMs. You can idle a car for a very long time and even just cruise around never putting much load on the engine and the plugs will not foul for 10's of thousands of miles. These extremely cold plugs like the ecoboost motors or predator motors run do just fine in these conditions.
I say theres nothing wrong with going to even colder plugs if you thnk you are going to be running the engine at high rpm and power conditions for extended periods of time. You are going to be worrying about burning them up more than fouling them out. Worst comes of it, you have to take them out and clean them with a propane torch or just replace them more often.

When I talked to NGK they were far more worried about how much a person changes the gap. Their plugs come pregapped and had a small range of not to exceed by, and they even stressed moving it in only one direction to the desired gap and avoid any back and forth stress on the strap.

The 6510's gapped down to .030 or less work great. Too much movement of the strap for NGKs liking tho as they start at .043.
NGK 95605's are the same heat range, come pregapped at .032, have a projected square platnium electrode which is preffered for boosted applications. They are Ruthenium which is a step above iridium for life of these very small electrodes. The smaller electrodes are the less energy needed for a spark to jump between them. So you might not need to run as tight of a gap or even touch the gap at all. The more gap you can get away with, the more consistant and stable combustion events you will get.

 

[beefcake]

It really comes down to power level and it also comes down to the year the car

You have to remember and 18 comes with a cold or plug already. They had a 11 to 17 car.

In general, as a rule of thumb, we usually go one. He range colder till about 800 wheel.

When I say 800 wheel that would be on any gen, so the 6510s or the Brisk 14s is what we typically run

From 800 to 1200 is Rio we usually go to the Briskrr12s.

12 to 1300-ish wheel we jump to the rr10s.

Also, the more boost the tighter of the gap

The only true indicator is to read plugs, make a pass, shut it off and pull the plug and read it and then you’ll know if you have the proper heat range or if the heat range you have is working

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