Spark Plug gap ?

[Stoner51]

I have a question on increasing the gap on my plugs.

What is the advantage to doing this?

I recently installed the hondata cpr and their information says you can increase the gap due to each plug having its own coil. It states it will cut down on misfires.

I don't have many, if any misfires that I know of unless I'm messing with the fuel tables and add one too many numbers.

I have used this for reliablilty not power. I am not looking to get an extra 10hp from this mod. My goal was to replace the single coil which is known to go bad. I already had an s300 so this seemed doable.

I'm looking for something like increasing the gap will burn fuel better allowing you to burn more fuel in the chamber and waste less out the tailpipe. Which would allow you to cut back on the fuel tables some, Or something along that lines.

I know many of you know much more than I do on these matters.

I am using Denso 673-2302 coils, they are from a 05 civic. They are OEM honda coils. I don't know what the stock gap on that car is but I feel I could go at least that wide.

thanks

steve

[sonikaccord]

I can answer the electrical part. Bigger gap=longer spark. This means more molecules of fuel have a chance to ignite. So I guess a more thorough burn.

[kapone]

it means it takes the spark longer to form, not a bigger spark...

If your engine timing is set at lets say factory 16 degrees, at factory gap (spark plug) , that spark will hit when your engine is at 16 degrees. by increasing the gap now you have affected were the spark will hit (say 18 degrees ) because it takes just that much longer for the spark to form.

So what you have to ask, is it beneficial for that spark to be hitting at a different part of the timing curve, and why...

[sonikaccord]

Kapone, please explain.

This is how I see it. If you move the electrode further away from the source of ignition your spark has to be longer to reach that distance. It has to break the insulation material (air and fuel) to make a spark.

What is the correlation between spark plug gap and ignition timing? I've never heard of that. The spark is traveling at approximately the speed of light. I dont think it will care about a couple of thousandths of an inch. That's analogous to saying if you use a longer audio cable you introduce some time delay which is true. The question is: will it be noticeable?

Edit: I pretty much asked the same question

[GhostAccord]

The reason for opening up that gap is to lengthen the spark and it's duration in the hopes that it will create a more complete burn of the air fuel mixture in the combustion chamber. It does not hinder the spark event unless you open it up to the point that it will no longer fire or gets blown out.

I always open up my gap from .044" to .055/.060". In doing this I usually see a small MPG gain and it always results in a smoother operation throughout the RPM range. Biggest thing is not to go too far and have the intake charge blow the spark out prematurely. It will become very apparent in higher RPM if you have opened up the gap too much. If you start to feel the ignition breaking up you will want to close up the gap a little bit, until you hit that perfect balance. it's a trial and error type of modification as each engine will give different feed back, depending on it's overall health.

[sonikaccord]

Ghost, how do you feel about stepping the ignition system voltage up to 16V? I've seen these little boost converters that are used to turn ~12v to 16v for coil on plug systems.

[GhostAccord]

I'll be honest, I have never looked into a 16v system. The 12v COP and distributor coils put out enough power I have never needed to look into a larger voltage input into the coil.

I've built some higher power and also higher RPM engines with and without COP that work just great with a 12v feed. Not sure what the gains of 16v are.That is something I will have to look into and see what the pro's and con's are. As far as I can see I'm not sure that there would be any real gain in doing a mod like this.

If it is like anything else Overclocking or overdriving a coil will only result in a faster refresh (higher frequency). Meaning that the coil will be able to fire faster with more reliability. It won't result in any more power being pushed out to the spark plugs. Also, driving a coil that is designed for 12v with 16v could, and more than likely would, result in premature failure. Besides, most of the pencil coils (COP) available can fire reliably up to 10K RPM in stock trim.