Congrats that you made some headway JW. And your suspicion of the base.
I say change the air filter before you drop the engine. What you describe as
sizzling is an indication of over-saturation (under-power) as several posts above suggest.
Sizzling at the end of a pull can also be over-drying of the wick (if you're running lower power). You've pulled too hard, or too often, or it's too much wicking for the capacity of the media you have installed choking flow (not enough airflow as well can keep it too wet). That'll give you some
afterburn when you let off. But, short of sputtering or spitting which can happen with too much power whether too wet or dry. Point being, the coil's too hot for the mix.
So there could be several issues in play as well. To better focus the convo we'd need to make sure it's not low-power wetting your connection. Was your base contact wet? If even a bit and you dried it out, how did it change the vape?
Limiting the air/juice flow's a nice stop-gap but I'm afraid it may not help find the cause in your case. If it's a clone, it could very well be fit. We can go down a million rabbit holes without knowing your exact set-up. For example, what is the metal comp of your Fasttech coils? We make the assumption too often that things
should work.
Like your RBA observation. It's spot on. It does work better than the OCC, even with the FT mystery wire. Don't you wonder why Aspire went to US made Kanthal? It's not because they know better. It's due to the influence of users here and elsewhere observing that their's
didn't work, imo. As to the ST RBA, it allows you to put in a more effective wire or build. Unfortunately, it lacks the airflow of the OCC (by design).
As for the small or larger side air-hole RBA's that replaced the good old originals, haven't you noticed how they're everywhere for sale? Especially clones. You could dial up the channel flow of the original RBA with a little delicate effort of tuning the feed channels. And it's needed because as the spec's tightened up for these tanks so did the need for air and juice flow precision. Our taste and juice variations require it. There's no one-size-fits-all. I guess that's really the illusion that we're struggling with.
As our gear has gotten better (in design) subtle changes to the hardware or aftermarket substitutes can cause major problems in performance. An example are clone bases which due to fit and alignment issues with the cores often produce some of the symptoms you describe.
There's a Spanish expression I love which applies here…
el que compra barato compra de cada rato.
Translation: He who buys cheap buys often.
Unfortunately with the FDA breathing down our necks there's little incentive for makers to keep up replacement parts support or quality. So it's ever more important for us to understand how the stuff actually works and particularly, to rebuild.
Good luck.
