Why does sub-ohm produce more vapor?

[Jockamo]

I know it to be true or at least I think I do. I'm mechanically inclined and crave more information. Do X and you get Y result doesn't really satisfy me. Is it because the wire can get to temperature faster? I would like to be able to see my coil while I'm using it but even with a glass chimney I suppose the vapor would obscure to view.
When dry burning, all coils look the same to me. I suppose the saturated coil needs a lot more power to produce more vapor. Just thinking....Why can"t I apply a large amount of power to a 1.5 ohm coil and get the same results as a .2 ohm coil? Or can I ?

 

[twgbonehead]

Yes, you can.

The amount of vapor depends on the amount of power (among other things).

For a given voltage, the power increases as the resistance decreases ( P = V*V/R)

You can supply identical amounts of power to a .2 ohm coil and a 1.5 ohm coil, but in order to supply the 1.5 ohm coil you need a higher voltage.

Mech mods can only supply a single voltage, and even regulated mods have a maximum limit to the voltage they can supply, so for many of the setups out there, the only way to get high power is to use low ohms. This is a restriction of the devices, though, not of the physics.

Thinner wire heats up faster, in fact, so at the same power levels a head wound with smaller wire should actually give better performance. But the wire size is only one variable, what with different coil geometries, dual-coils, parallel coils, twisted coils, etc....

 

[p7willm]

There are a lot of variables. The major one is that it takes power (watts) to convert the eliquid to vapor. Take a look at an ohm's law calculator and you can see that you can get the same wattage no matter what resistance you have if you can get the required voltage. with a resistance of 50 ohms you would get 100 watts with 70 volts. when the coil got up to temperature it would produce about the same vapor as a .17 ohm coil at 4.2 volts.

We don't have 70 volt mods yet so .17 at 4.2 is far more common.

You also need to wick the juice so it can reach the coil and turn to vapor. Even though you are able to put a bunch of watts in a coil if it can not get enough liquid to the coil the coil will get too hot, burn the liquid, and not produce as much vapor.

You need to take the surface area of the coil into account. if there is more area contacting the liquid you can get more vapor. This is why "strange", dual wire, clapton, etc., coils will deliver a little more vapor. Although a .2 ohm normal coil will probably have more vapor than a "strange" .19 ohm coil.

You need to have air flow to remove the vapor and allow more to be created. Air flow through the middle of a coil with juice around it might be better than air flow around a coil with juice inside it.

There are a lot more subtle things that will change the amount, and flavor, of vapor produced but the major thing is that more watts produce more vapor.