Originally Posted by Ribwizzard
But your still pushing air through either a 3.25 in or a 4.0" orifice, so the beginning of the pipe, the orifice is what will dictate how much volume can enter the pipe, or exit the cooking chamber, right?
Or does the hot air rising in the pipe actually create that much draft to overcome the orifice size?
Do you guys think that either18 inches of 3.25 id pipe or 12 inches of 4.0 id pipe will perform the same when it comes to and exhaust stack?
No I don't. but that is only an opinion
I would opt for shorter length and larger diameter.
There has to be some restriction the narrower the pipe... adding more length to a narrow pipe will not draft or draw as good as a shorter pipe with a larger diameter.
Maybe adding a little length to a 4" pipe in place of a shorter 5" pipe would be ok, but there's got to be limitations... lets say a 2" pipe would have to be 8" long, I don't think that would work as well as a shorter larger diameter.
I may be wrong but wouldn't the pressure increase in a smaller diameter, taller pipe??