Trying to better understand the cost on UBIT (Unrelated Business Income Tax)

[Gregg Truex]

I am purchasing a Short term rental and would like to better understand the potential tax costs of having a self directed IRA vs a self directed 401K. I understand that the 401K is not subject to UBIT but I don't know in a Self Directed IRA how those costs are detailed and calcutlated.

Does the cash flow from the short term rental get taxed or does when we sell the asset do the capital gains get the UBIT tax.

Is there someone that could help me with this? Thank you.