Exhaust(ing) question

[smooookin]

Today I started working on the XXL UDS my question is how big the exhaust should be.

I found a 4 inch roof vent that would be perfect for what I want. I didn’t buy it today because I am thinking I might need to go bigger.

Thoughts?

 

[Bbq Bubba]

I would think 4" would be suffecient, you gonna have the standard 4 intake hole's but probably larger than normal
Heat rises so the drum act's like a natural chimney as far as air draw goes IMO.

 

[smooookin]

I would think 4" would be suffecient, you gonna have the standard 4 intake hole's but probably larger than normal
Heat rises so the drum act's like a natural chimney as far as air draw goes IMO.

Actually I think I am going to go with 4 or 5 1/2 nipples.

She's gonna be a big one. I took several pictures along the way. Here is one of them.

I will post a thread later as I have to leave town in a couple of hours for the weekend.

 

[Dr_KY]

Why not 3/4 or 1'' nipples?

 

[smooookin]

Why not 3/4 or 1'' nipples?

I was once traumatized by big nipples.:lol::lol:

Actually 1/2 is what I have. (cheap mod)

 

[N8man]

You don't think 4" is gonna be too big, do you? Just saying that there maybe a fire control issue with too big of an exhaust or too much draft...But, you are venturing into unknown territory with that Behemoth DrumPit you're building.
Perhaps there are some intake to exhaust ratios pit builders use to determine
flow volume.

 

[Bbq Bubba]

Look's like a good start, hardest part will be getting them door's to seal tight!!
Ya can't tease us like that and then leave!!! :shock:

 

[smooookin]

You don't think 4" is gonna be too big, do you? Just saying that there maybe a fire control issue with too big of an exhaust or too much draft...But, you are venturing into unknown territory with that Behemoth DrumPit you're building.
Perhaps there are some intake to exhaust ratios pit builders use to determine
flow volume.

I am thinking four inch going by the exstensin I have going right now. Just using the 2 in opening and the 3/4 (?) in the top was not enough. I cut a hole almost 2in in the top, in addition to the 2 in bung onpening, with three caps out today she has run 240-245.

 

[Azinine]

off topic, but how many cooking grates are you planning on having in that sucker?

 

[N8man]

4" exhaust it is. Man, that's gonna a BEAST!!!! Good Luck with your build and I look forward to seeing it smoking some meat!!!!

 

[Meat Burner]

Smooookin, did you get my e-mail?

 

[smooookin]

off topic, but how many cooking grates are you planning on having in that sucker?

One in the top for beans corn etc and one at the bottom for a catchers mit!:biggrin: everything will hang under the top grate.
If needed I can put enough grates in to do approx 30 butts.

 

[RichardF]

I was once traumatized by big nipples.:lol::lol:

Actually 1/2 is what I have. (cheap mod)

Like these

 

[Dr_KY]

I was once traumatized by big nipples.:lol::lol:

Actually 1/2 is what I have. (cheap mod)

I know the feeling

With the height being what it is have you considered running the top vent off the side of the highest point of the top drum so you can adjust if need be? * Pull and pok with a broomstick mod*

 

[ipls3355]

Make sure and document how you get the doors to seal. I am thinking of making one of these.

 

[CritterCook]

Richard, the fact that you found that ad seriously disturbs me.....the fact that you posted it makes me laugh.

As for the 4" exhaust....to big, not big enough? put a gate valve on it and make it whatever size you want.

 

[jestridge]

In my opinion 4" might be a little large. You could put Two 2" then close one when it got up to heat.