After Todd’s suggestion to make the pyro a particle sourced sim, I have created a popnet for the particle emission and a pyro dopnet which sources those particles. The whole sim is much easier to control now that it is particle based and has some natural disturbance from the particle emitters interacting with each other.
The popnet is where most of the changes happen. Currently it is a simple set up using only drag and wind. The variation and swirls are created from the wind node. Turbulence might be added later.
The pyro has some dissipate and turbulence on it to make some variation and wind to put it with the particles. I had put drag on there at one point, but that was pushing the smoke too far back, revealing little smoke balls come out from the sim.
On the left is the network for the particles. In the middle and in the viewport, is the proxy collision geometry because the exhaust pipe from the car had several holes in it which let some of the smoke escape. On the right, is the rendered exhaust pipe.
Since we plan on using Arnold in Maya, I cached out the VDB to bring into Maya to see what it will look like.
Using aiVolume and a aiStandardVolume shader, I saw that it seems a bit wispier than it appeared in Houdini. It might be due to the shader settings. I feel the thickness of the exhaust is pretty accurate to what I am going for though.