So im thinking bout getting a jb4 . Knowing once you get one, you have to gap your spark plugs. Now my question is, lets say I do all this then want to visit my dealer *im still under warranty 18k miles on car* and I remove the jb4, would my drivetrain be affected because the spark plugs are gapped and the tune is removed? If not what's the ideal time frame to drive with gapped plugs and no tune on the car.
Question about tune..ish
- Thread starter dollah
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oddball
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You have to reduce the gap on the spark plugs. Higher chamber pressures, like from higher boost, can cause the spark to fail. It's called "blow out" but it's not literally like a candle. With higher chamber pressures there's more air/fuel molecules between the electrodes, so it takes more voltage to kick off the spark. The stock ECU runs the ignition coils right on the bottom edge of power - juuuuust enough energy to light off the spark plug in the stock configuration. The time spent building a charge in a coil is called "dwell". More dwell = more energy, but more heat that can cause the coil's insulation and windings to fail. Less dwell = less energy, runs cooler, lasts longer, etc.
Tightening the gap makes it easier to spark, so now that energy is enough to fire the spark even with the higher chamber pressures. It'll run exactly like stock at the stock pressures with the tighter gap.
In general, a larger gap makes a larger spark which will have a better time lighting off the charge. But that bigger gap requires more energy and can cause erratic spark if the rest of the ignition setup isn't up to the job. So it's a balance. Tighter gaps are fine, especially if the car is running on quality gas. 0.035" has been a common spark gap for decades, so OEMs are going to try to stick with that for simplicity (pre-gapped spark plugs from manufacturers, abundant supply chain, etc). Bigger gaps are useful when the gas is terrible or the engine has a poor design resulting in a poor mixture distribution in the chamber. e.g. my classic Oldsmobile runs 0.060" gaps because there's *no* swirl in those old engines, it has a huge bore, and needs every last bit of help it can get. But it also has a dedicated multi-spark capacitive discharge box.
Gap them whenever you want. The techs won't have any idea unless you write a huge note on the hood saying you did it, or break a bunch of stuff in the process. They also can't tell that a JB4 was there unless you make it obvious.
"Performance" coils won't help. The problem is how the ECU is driving the coils. That's why the ECU flashes, like Tork, change the dwell tables to push more power into the coils so you can run the stock gap.
Tightening the gap makes it easier to spark, so now that energy is enough to fire the spark even with the higher chamber pressures. It'll run exactly like stock at the stock pressures with the tighter gap.
In general, a larger gap makes a larger spark which will have a better time lighting off the charge. But that bigger gap requires more energy and can cause erratic spark if the rest of the ignition setup isn't up to the job. So it's a balance. Tighter gaps are fine, especially if the car is running on quality gas. 0.035" has been a common spark gap for decades, so OEMs are going to try to stick with that for simplicity (pre-gapped spark plugs from manufacturers, abundant supply chain, etc). Bigger gaps are useful when the gas is terrible or the engine has a poor design resulting in a poor mixture distribution in the chamber. e.g. my classic Oldsmobile runs 0.060" gaps because there's *no* swirl in those old engines, it has a huge bore, and needs every last bit of help it can get. But it also has a dedicated multi-spark capacitive discharge box.
Gap them whenever you want. The techs won't have any idea unless you write a huge note on the hood saying you did it, or break a bunch of stuff in the process. They also can't tell that a JB4 was there unless you make it obvious.
"Performance" coils won't help. The problem is how the ECU is driving the coils. That's why the ECU flashes, like Tork, change the dwell tables to push more power into the coils so you can run the stock gap.
Volfy
1000 Posts Club!
^well said. I agree service techs are not going to flag your car as modded, just because you've got aftermarket plugs gapped tighter than stock. That's if they bother to check. Unlikely, if there is no reason to.
FWIW, I've got JB4 in all our Stingers and G70, running NGK ILKRQ7G, which are pregapped at 0.028". For the track, we run map 1 or 2, but for everyday driving, map0 only, which are most of the miles put on our cars. For me personally, I'm much more likely to hypermile on everyday commuting, so the ECU is constantly leaning the mixture as much as possible, no doubt stratifying the intake charge often, per the way I drive. I have yet to notice the slightest bit of drivability problem. That said, I live in the warn south, so very little experience with extreme cold conditions, where gasoline would be more hesitant to flash into gaseous phase and more likely to stay only finely atomized droplets. That might possible make the intake charge more difficult to ignite.
Ans, yes, bad gas, or stale gas, that has lost the more volatile fractions would also present a ignitability problem. As long as you are driving your car frequently and you buy your gas from a busy corner gas station, that should not be an issue.
FWIW, I've got JB4 in all our Stingers and G70, running NGK ILKRQ7G, which are pregapped at 0.028". For the track, we run map 1 or 2, but for everyday driving, map0 only, which are most of the miles put on our cars. For me personally, I'm much more likely to hypermile on everyday commuting, so the ECU is constantly leaning the mixture as much as possible, no doubt stratifying the intake charge often, per the way I drive. I have yet to notice the slightest bit of drivability problem. That said, I live in the warn south, so very little experience with extreme cold conditions, where gasoline would be more hesitant to flash into gaseous phase and more likely to stay only finely atomized droplets. That might possible make the intake charge more difficult to ignite.
Ans, yes, bad gas, or stale gas, that has lost the more volatile fractions would also present a ignitability problem. As long as you are driving your car frequently and you buy your gas from a busy corner gas station, that should not be an issue.
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Now do you suggest me gapping spark plugs and to what size even if I don’t tune it ? I do have intakes, Xpipe, intercooler and snorkles only.
Volfy
1000 Posts Club!
Gap depends on which engine you have, which plug you go with, and what maps you intend to run, once you get the JB4.
As to how to gap the spark plugs, there are some pretty fancy gapping tool you can buy. I have always just used the same old gap tool/gauge I've had for probably 35yrs. Even today, you can buy one for less than a dollar.
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I planned on the JB4 but I decided to wait on it , I was gona go with HKS spark plugs but I’m just not sure what to gap them too if I’m not tuning the car
