The Texas BBQ Forum

what if anything happens when your firebox is to big. I mean as long as you don't overfill it I don't think there would be any problems. what do yall think

Too large a firebox changes the way a cooker drafts.
If you watch the calculator numbers A 24" x 4' cooker with a 20" Sq. firebox is about 110% over sized and requires a 4" chimney 32" tall. If you increase the firebox size to 24" Sq. you are now 191% and the same 4" exhaust would increase to 55" tall to compensate for the extra volume in the firebox. You can also manipulate the 1/3 rule here by adding a larger diameter exhaust but your draft iwill still be stronger than keeping a balanced 1/3 design.
Will it work? Sure it will once you learn how to control it.

It's going to be interesting. The guy that cut the pipe for my firebox cut it to long. That was all the steel I had. Cook chamber is 37 inches and my firebox is 24 inches. I hope it works out.

great news, I was able to contact my welder today and he said he did not cut the pipe yesterday like I thought he did. I went back and did my calculations and by box will be at about 113.6 percent size diff. I am so glad!