My review of the fullsize glass Vivi Nova and full size Davide in the new BDC format. I picked up these two BDC clearomizers (glassomizers to some) in a CoOp through the ECF forums. Which is a really nice place to get in onsome really good deals. If you don't know what a CoOp is, look it up, or go to the CoOp section of your favorite forum and poke around a little. Just make sure you read any rules that are posted. I received and began to unbox my order. One thing I noticed is that the Nova was packaged in just a cellophane wrapper, and only had one of the BDC heads which was already installed. The Davide was in it's normal cardboard box and plastic tray packaging but it seemed they used the same boxes from their Kanger style single coil Davide and just added a few stickers to identify it as the BDC style of system. But it did come with 2 heads. One installed, and one extra. The Vivi Nova-S BDC glassomizer: My first experience with these BDC (bottom dual coil) “glassomizers” was the Vivi Nova. I chose this one mainly because I've never had one and wanted to seewhat they were all about. I started out with a 2 hole 1.8ohm head and some of my home blended high VG juice on my USB VV pass-through set at 3.0V. After the first couple of puffs it started to gurgle, then drown, then it got to the point where I was just drawing liquid, and my juice was leaking out all over the battery connection. It has a fairly tight draw compared to the Evod and single Kanger coil Mini Davide I was use to. I was thinking that I may need to drill out the air feed holes a bit to get this thing to work correctly. But I later found out that this may not be the problem. So I clean everything out, dial up my voltage on my pass-through, and tryit again. At 3.6V the same thing starts to happen but after more draws. Once itstarts to gurgle I upped the voltage again. This time all the way tothe 4.8V limit on my pass-through. This stops the gurgling and turns the Nova into a cloud maker. The only problem is that it also mutes the taste of my juice. So I drop the voltage down to 4.2V. This seems to keep it right on the edge of gurgling, yet still gives me some descent flavor, and gives a nice, rich, thick cloud of vapor that, at times, gives you a throat hit even for a mostly VG juice. The heads on these are not interchangeable with with any other heads, as far as I can tell. Kanger single coils will thread up to the base, but their chimneys are too big around to fit in the Nova's centertube. The Davide-S BDC glassomizer : After my experience with the Nova I was expecting the same, or similar performance out of the Davide. This was not the case. I can best describe the vapeing qualities of the Davide as the polar opposite of the Nova. I've run a few different flavors through this tank and it seems to not like it when you take it above the 3.0V mark. I am again using a 1.8ohm, 2 hole coil and my USB VV pass-through. This thing seems to be having draw issues to the point as to where it seems it can't get enough juice into the coils to keep from getting burnt hits. At the lowest 3.0V setting on my pass-through I can still get a slight hint of a burning taste when drawing normally. If I do a hard draw the burnt taste goes away. I can't go any lower on voltage, and, from what I'm gathering, most APVs don't preform well below 3.7V. So this may turn out to be a problem for people who like to use APVs, and Mods. But there may be a solution. The makers of these coils (Nhaler from what I gather) started this project with a 4 hole head. But evidently it started to receive some complaints from people who were having a similar flooding problem as I had with the Nova. So they decided to cut the the wicking holes back to 2 holes to keep the coils from flooding. They did, however, ship a few of the Davides with the 4 hole, old style heads, installed in them. I happened to get one of these. So I changed out the 2 hole head for a 1.8 ohm 4hole head and gave it another go. What a difference! I still get a crackling sound(not a rattle snake sound) coming from the coil while I'm vapeing. But the flavor has greatly improved. I'm kind of hoping that Nhaler keeps the 4 hole design and offers it as a replacement coil option. If not, the Davide (at least mine) will windup in one of my drawers collecting dust unless I just put single Kanger coils in it. The vapor production isn't AS much as the Nova, but it is still way above my single coil Evod and Mini Davide. The main thing that I like about the new style Davide-S is that it was designed using the old Davide. It just has a few extra parts added to make the BDC coils fit. So what does this mean to someone who's actually reading this? It means that you can take these “added” parts off the Davide-S BDC,screw a standard Kanger single coil into it's base, thread it up to the bottom of the tank and vape it just like the old BCC Davide. It means that both the BDC and the BCC coils will work in the new Davide-S!! It's like getting two vapeing systems in one device. My final thoughts: My experiences with these two tanks so far has been fairly positive. I would say these are not a good device for a vapeing beginner, at thi spoint, as there is somewhat of a learning curve to get these tanks to operate correctly. They have to have the right heads in them, that are fired at the right voltage, or they will leave the user feeling a bit frustrated. But after you get these things dialed in they work fantastic! In my experience, I would not trust the Vivi Nova to anything other then a VV device that can handle voltages in the 4.0-6.0v area until they can address the flooding issues at lower voltages. I would recommend the Davide-S for people who have those little eGo style batteries that have only one voltage setting (starter batteries as I call them). I set the Davide on the one I have and it worked excellent on it. So again, if they can tune these heads in correctly, this will be one outstanding glassomizer. Both of these units produced a nice, thick, rich, vapor for me using my high VG juice. But keep in mind, the more vapor you are producing, the more juice you will be using. In the week since I've started testing these two tanks I've gone through about 30ml of juice. That's allot for me. Now a word about the heads. As I mentioned before, the Davide's BDC heads can be switched out for the Kanger style single coil heads and used in the Davide. What I found is that when you do this, it loosens the draw quite a bit. So some of the problems I have been experiencing, especially with the flooding in the Nova, may have something to do with how small the airintake hole is at the bottom of the coils, and how tight the draw is. If your not pulling air, your pulling juice. Others I have talked to have had different experiences with these same tanks and coils. So there may also be a problem with the consistencies inthe manufacturing of the heads. After seeing a few people take these heads apart it is apparent that these heads are not rebuildable. They use two different types of wire (a resistant and a non-resistant wire) fused together to make up the coils. This way your not heating up the silicone insulator the wires travel through in the bottom ofthe coil. They also use small silicone sleeves on the lead wires to the top coil so they don't ground out on the coil body or short tothe bottom coil. There may be some out there who will get adventurous, and attempt to rebuild these coils. I hope they post video of it. But for most of us, we'll have to buy our extra coils. One last final thought. This BDC system is a step in the right direction. It is right now setting industry standards. I'm hoping the improvements to this system keep coming. But there is one area that a few Mod makers have addressed,and I WISH the tank makers would look into. That is variable airflow. You can get adjustable airflow in drippers and RBAs. Now we need a bottom coil tank system with adjustable airflow. If we could get it in a system such as this, and again, do something about the wicking on the heads, I think they would be creating an almost perfect system.....for now. Thank you to all who have read this. I hope it will help you in your research into these systems, and will shed some light on my persona lexperiences with them. Or, if nothing else, I hope it was at least entertaining reading.