UDS airflow idea

[Ufo8mycow]

I picked up an 85 gallon salvage drum to build a new uds out of and I have an idea that I am considering and would like some opinions.

On my current 55 gallon uds when I have used my pit master iq 110 and now with my new guru CyberQ it seems like it is blowing more air in than it should be and is cooling off the pit. To be clear I’m not talking about draft, the fan is actually blowing out I have to close down the dampers manually to restrict how much air it can move.

I have a 1.5” tube that will go into the bottom center of the drum directly under the charcoal basket and ash pan so that it should evenly distribute air around the drum instead of from one side only.

I am also thinking about making a disk that will fit between the basket and drum wall so that all or at least most of the air will be forced to go through the basket instead of around it.

I haven’t decided how high the ring should be so I am thinking about making it adjustable bu using shelf rails and brackets to hold it and the cooking grates.

Hopefully the drawing that I have attached will make it clear.

[SmittyJonz]

A couple guys on here done that - if I remember right they said bottom intake didn’t help much and went back to side intake or a tube Intake thru the side.

[ebijack]

There are UDS companies that place the intake under the coal basket these days.
You did not mention what temp ranges you want to cook at. If you are wanting to get easily to 550* plus you will need to at least double your intake. Also your exhaust size and how/where you place it can make a difference in available temps. I use 3- 1.5" pipe elbows in order to get 700* plus on my 55 gal drums. And 3 5/8" minimum exh hole. I can only get to 650* in really cold weather with that 3 5/8" exhaust. My other drum I have 4 1/2" total exhaust and can get over 800*.



I tried the air under the coal basket in one of my UDS's for a good 6 or 7 mths and saw no difference/gain in the performance between either of my drums. With the intake under the coals, vs intake air coming from the side of the barrel. I do have my intakes placed low, at/near the bottom of each barrels.
Anyway, this was my way I came up with a few years ago to get the air under the coals and see if it actually made a difference. To not have anything in my way from sweeping up all the ash out of the drum after cooking. And no chance of the ash build up choking off the air.
I only covered 2 of the intakes with a shield for direct air flow under the coals. The shield is attached to the bottom edge of the coal basket grate. So it lifts out with the coal basket. I made the shield to keep the basket in the center of the drum.


The bottom of the grate is 3" up off the bottom. I have since gone to 4" legs for more room for ash on really long cooks.

I ended up removing that air shield. No added benefit. That is my experience.
Your riser intake tube is also very restricting for max temps. Fine for low n slow. When I add this, I can not get above 315* using 1- 1.5" pipe intake with the shorter extension.

[Nuco59]

Looking forward to seeing how it works out for you. I'm always interested in the ways folk tweak their drums and other cookers. I've pondered fans and atc units for my old uds. It was a fun thing to think about- but I never did it. I don't do extended cooks and -for the most part- our temps are mild here in the Dallas area. I might not get trouble free 14 hour cooks at an unwavering 275* but it does ok for what it is.

Keep us posted?

[lastmajordude]

Hunsaker has the intake under the bottom and some folks complain of grease dripping....if that’s the case a pipe might have clogging issues....just my 2 cents.....almost all my grease evaporates on the the charcoal basket or hot bottom.....

[Ufo8mycow]

I got her built and have done a test run with the exhaust and intake fully open last night and she went over 450* I did add a second hole in the side for additional air flow if I need it but this is for smoking, I have a gas grill and a Weber kettle if I want to get that hot.

Today I sprayed her down with veggi oil and seasoned at 250* for as About 4 hours until the charcoal ran out.

I am going to pick up a few racks of spares in the morning and give her a real test.

[ebijack]

Originally Posted by Ufo8mycow

I got her built and have done a test run with the exhaust and intake fully open last night and she went over 450*

Just note, do not expect to be able to hit and maintain that temp when you load up the drum with meat.