This is one experiment I have not shared with everyone, because Lee gave us a good example what happens when a "bubbler" or scrubber is not used to filter the HHO before it enters the intake area.
What I did was run a cell for 8 hours straight (this is when I was using KOH) without a bubbler, straight from the reservoir. Pointed the outlet in a simulater intake with a throttle body I got from the junk yard, even small trace of KOH is carried through and eventually coat the surface of the butterfly is will attached itself to the surface and slowly eat away at the part. specially if it is made of aluminum, so if the grid up aluminum is used to filter the HHO and any small amount attached itself to that the filteration. It will make HHO even after the system is turn off, because that activity is doing it's own things in what even size tube or canister you are using as a filter.
Maybe I am missing something here, with two bubbler set up and running the HHO through an "air stone" to break up the huges bubbles which is carrying KOH fumes through some vinegar, then run it through a heat exchanger should eliminate any fumes with KOH being induced in the intake.
I have 22K on my F-150, at 20k I inspected the system including the throttle body. There was no sign of corrorion, then again I've been trying to keep my system simple to the point of less and less maintenance is required. so if I am missing something someone wake up this "olde salty chief" so i can learn something new.