Why not to use Seafoam in every tank for FE

[dkjones96]

No, there are no threads about that I don't think. A larger gap means a larger spark, a larger spark means more heat and a better burn, especially in lean mixtures. The only thing is you can't just increase the spark gap size without effecting timing. More gap means more voltage which means more time for the coil to make the required output to fire the plug, essentially retarding timing.

You have to be careful with gap though. A lot of cars that came with Iridium and Platinum plugs have their coils designed with a shorter tolerance for over-voltage situations and they can die very quickly.

[bobc455]

Originally Posted by RningOnFumes

That's an interesting statement. Are there threads here or on the interwebs which support that? I ask because this is the first time I've heard of it.

That's true in theory - biggest gap = most efficient combustion (until the point where you get misfires). There are downsides to a huge gap, but MPG will theoretically benefit.

I used to run a 0.065" gap on my Buick. Come to think of it, maybe I'll try that again.

Originally Posted by dkjones96

More gap means more voltage which means more time for the coil to make the required output to fire the plug, essentially retarding timing.

Nah, every coil around can build up plenty of voltage, it won't affect timing directly. If you watch a car with MSD on a scope, you'll realize that a coil can build up voltage about a hundred times faster than it really needs to.

However a larger gap will also REQUIRE more voltage, especially under heavier load. The more mass (air/fuel) in the cylinder, the harder it is to initiate the spark - and if the spark doesn't have enough "juice" to fire, then you completely miss that combustion cycle (which really will kill your MPG altogether). Generally your super-high HP race cars will run a very tight gap just because it is so hard to get a spark to jump from the electrode (or to the electrode, whatever).

For example when I run my Buick "day-to-day", I am fine with a gap of about 0.042". However if I go to the track and hit the nitrous, I have a different set of plugs which are set to 0.028" (and much colder heat range obviously).

-BC

[dkjones96]

A CDI system does develop voltage way faster than it needs to because the coil is just a transformer but an inductive coil doesn't. Inductive coils are slower and increasing the amount of voltage they need to put out over stock by a lot can cause timing changes. Most electronic spark systems can handle the changes.

Coil over plug applications do have trouble running excessive gaps. I've experimented with newer Hondas and had them start misfiring at .052 when their stock gap was only .044. The plugs they come with are built to only minimally open over their rated lifetime. Double platinum plugs can go 100k miles before they open up even .005", but after that it just depends on that particular plugs construction. Every one of them will be different after that, thus the rating to 100k.

[thisisntjared]

Originally Posted by bobc455

However a larger gap will also REQUIRE more voltage, especially under heavier load. The more mass (air/fuel) in the cylinder, the harder it is to initiate the spark - and if the spark doesn't have enough "juice" to fire, then you completely miss that combustion cycle (which really will kill your MPG altogether). Generally your super-high HP race cars will run a very tight gap just because it is so hard to get a spark to jump from the electrode (or to the electrode, whatever).

For example when I run my Buick "day-to-day", I am fine with a gap of about 0.042". However if I go to the track and hit the nitrous, I have a different set of plugs which are set to 0.028" (and much colder heat range obviously).

-BC

this was my understanding as well, but i am no expert.

[shatto]

This is about how the plugs from my Dakota looked after 30,000 miles....on an engine with 500,000 miles on it....that never had Sea-Foam in it.

[GasSavers_bobski]

Originally Posted by dkjones96

A CDI system does develop voltage way faster than it needs to because the coil is just a transformer but an inductive coil doesn't. Inductive coils are slower and increasing the amount of voltage they need to put out over stock by a lot can cause timing changes.

For starters, transformers are inductive coils. One coil produces a magnetic field, which induces current in the other.
Traditional coil ignition systems operate as a sort of one-shot transformer, as opposed to constantly oscillating as you see in typical AC transformers. The ignition coil has two internal windings: A 12V winding connected to the car's ignition control electronics, and a high voltage winding connected to the spark plugs via the distributor cap and/or wires. The car's ignition circuit energizes the 12V coil at all times, except when firing the ignition. The idea being that the 12V coil creates and maintains a magnetic field that covers both windings... When power is removed from the 12V winding, the magnetic field collapses. The motion of the collapsing magnetic field induces current in the high voltage winding.
A similar induction of current could be achieved by switching on the power to the 12V winding, but in practice it is difficult to provide the necessary surge of power. It's easier to set up the field between ignition events and let it collapse as fast as possible as needed.
The circuit attached to the high voltage winding (the distributor cap, wires and spark plugs) has a very high resistance, so the voltage in the coil has to ramp up to very high levels in order to force the induced current to flow through the circuit. Increasing the spark plug gap would increase the apparent resistance on the high voltage section of the ignition circuit, resulting in higher output voltages.
Since the ignition coil's magnetic field can collapse nearly instantaneously, it can produce current and thus a voltage spike in a similarly short instant. That means the time it takes for the voltage to ramp up is a function of the high voltage circuit's net capacitance - how much energy the spark plug wires and such can store due to electrostatic attraction. The higher the voltage you apply to a capacitor, the more energy it stores. That means that as system voltages increase, more energy will be stored in the capacitance of the components, making the ramp-up take longer.
To reiterate, this delay is not a characteristic of the device producing the ignition system's high voltage, but rather of the components down stream. If one were to reduce the capacitance down steam by, for instance, shortening the spark plug wires, the ramp-up would be faster.