Kanger Subtank Mini RBA Deck Airflow Modification

[EarnestAccord]

I've owned the Kanger Subtank Mini for a couple of months now. I'm a flavor chaser and was fully enjoying their prebuilt .5ohm OCCs. Nice open draw, low temp when ran at 30w and great flavor. What I was very dissapointed with was their RBA deck. Its' airflow was so restricted it was a completely different set-up compared to their OCCs. While I like the OCCs I'm not thrilled about being dependent on buying new ones every week or so and like the ability to tweek my coild to optimize my vape experience.

I assumed it was my coil builds that were doing this so I worked my way through everything from small 2mm horizontal coils to large diametered vertical coils, all attempting to allow the airflow the least restricted path as possible. Fast forward a few months of me trying all of this and finally getting a build that I new was in no way getting in the way. Problems were had with wicking (burning after a day or so) when I went with a slightly larger diameter coil than the air inlet below the coil. To create more room between the coil and the deck's posts, I choose to build a rectangular vertical coil, essentially keeping the same volume but changing the shape. An oval would probably work just as well but I happened to have a good rectanglular coil wrapping tool already so used that.

It finally only improved the air flow slightly. Then one day as I'm changing out coils I notice the .5ohm OCCs bottom four air inlets and compared them to the RBA deck's.

Huge difference in size! So I decided to modify. Luckily the air inlets on the RBA are on a removable threaded tube. Seperated the assembly and purchased the smallest diamond headed dremel bit I could find.

Spent 5 minutes drilling it out:

And problem solved! She pulls nice and open and is only slightly more constricted than the .5ohm OCC. It is such a difference though I think I'll try it for awhile and maybe bore it out some more if I feel the need to. So if anyone hates the RBA's airflow, but doesn't want to go buy a different subtank, a $5 bit and a steady hand could save you some money.
Enjoy

 

[jefx]

I did this a while back with the original rba. But I used a dremeled cut off wheel. It definitely helps, but most of the restriction seems to come from the bore of the air hole.

 

[VapeRN]

It's not just the small chimney diameter that is so restrictive?? I guess I have to try this out, since I hate the airflow on this with the RBA in.


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[Mike H.]

Ive done this to more restrictive tanks like an evod or a kayfun and a taifun GT...keep in mind too much air flow and you lose the wicking abilities..There has to be some restriction to allow pulling in the juice to the wick...The more air flow you have the harder youll have to suck to keep the wick juiced...Just something about getting a dizzy head having to suck your brains out i dont care for.

 

[EarnestAccord]

Ive done this to more restrictive tanks like an evod or a kayfun and a taifun GT...keep in mind too much air flow and you lose the wicking abilities..There has to be some restriction to allow pulling in the juice to the wick...The more air flow you have the harder youll have to suck to keep the wick juiced...Just something about getting a dizzy head having to suck your brains out i dont care for.

Ohh.. I never thought of that. So the negative pressure created by the constricted air flow helps pull ejuice into the wick and coil...this is probably why the OCCs have such a thin layer of wicking, to compensate for little if any negative pressure.. Big problem for my vertical set-up in the RBA as there is a ton of wicking in there..

 

[EarnestAccord]

To be honest I think I was a little too excited about the outcome of my original modification. Yes, it increased the airflow, but when I compared it back again to the OCC's it is still a far cry. Obviously this leads me to wanting to bore it out more, but with the comments above questioning whether the issue might be in the chimney or main bore hole on the deck I tried a proof in concept. Took the bottom threaded air inlet completely out and hooked her up, obviously no power but the air flow is now comparable to the OCC.

So I'll go at it again when I get some time and see if it helps. The one problem I could see happening at this point, is if the constriction is actually happening with the air inlet tube it's self. Notice how much smaller it is and that wont have the ability to be modified.. Crossing my fingers.

 

[VapeRN]

I think the vacuum effect is overrated in these tanks. Wick to juice contact and amount of wick are probably more important. 1cm sq or so of saturated OJC can hold more than enough juice to fire a .5ohm coil for a full hit. I think vacuum is more of an issue for chain vaping, but still, there just needs to be air in the coil head to allow wicking to naturally happen.


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[EarnestAccord]

Here's my update, drilled the RBA's Inlets as far as I could without compromising structural integrity, did improve the airflow some more, but sadly not to the level of Kangers OCCs.

Will probably be looking for another single coil RTA. The only one that seems to be definitively wide open airflow, that's still a single coil, is the Morph by Ehpro/Eciggity. Though all the conversion bases are cool I dont really want all that nor want to pay for them. Why are there no single coil RBA's with wide open airflow out in the market?

 

[EarnestAccord]

While I Was able to improve the RBA and will probably still use it as a back-up I've found a better solution. I figured out how to rebuild the prebuilt OCC v2. Now I get their awsome performance, even a bit better in the flavor, at a fraction of the cost. Hope this helps.

http://vapingunderground.com/threads/rebuilding-kanger-occ-v2.139587/