Modifying a Yoder Witchita

[Adamg]

First post here but I was over at the smoke ring for a while then drifted away and now see it’s no more so here I am.

Unsure where to stick this since it’s a commercially produced smoker and not a fresh build so hopefully here is alright.

I bought a loaded witchita 12-13 yrs ago and have never been impressed with air movement and cook chamber temp swings. The only thing I changed was added a heat management plate, back then it was an option, not standard. I’ve tried every combination of fire management practices I’ve read about, some better than others but nothing still great in my opinion.

Way back when I remember reading how yoder made the firebox to cooking chamber openings way to big and there was some discussion about closing the gap up, but now when I google search I cannot find any info related to that.

The feldon calculator says the half moon opening should be 11-12” or so. Is there any merit to welding a plate and closing the gap to something close to this size?

And also, mine is old enough to have a welded exhaust stack. Feldon says 25” or so for the 4” pipe. Mine is 18” (I think) when measured from top of cooking chamber. Again, would that be worthwhile to extend?

In the photo, the heat management plate is at top portion of the opening, but it doesn’t completely block off the hole so it would seem that it would not close down the total area of the opening.

Mainly I’m just looking for better and more consistent airflow / draw of this cooker

Thanks in advance!

 

[JckDanls 07]

Phew... Where to begin...

First... Did you put that plate in the (from top-down) opening from FB to CC ??

Second... Run your numbers through this Calculator... Then see where we are at... He recommends 32-36 inchs of stack above the CC ... Just run your numbers and compare to actual measurements ..

I built mine (link in signature) to his numbers and it works great...

Edit... Forgot to add link below

Reverse Flow Smoker... How to calculate build tutorial...

> Reverse Flow Smoker... How to calculate build tutorial... By DaveOmak This is a tutorial and you will need a calculator and paper to note desired dimensions... This tutorial has been proven to make an excellent operating Reverse Flow smoker... Here's to "Alien BBQ" and the folks that first...

www.smokingmeatforums.com

 

[Adamg]

Phew... Where to begin...

First... Did you put that plate in the (from top-down) opening from FB to CC ??

Second... Run your numbers through this Calculator... Then see where we are at... He recommends 32-36 inchs of stack above the CC ... Just run your numbers and compare to actual measurements ..

I built mine (link in signature) to his numbers and it works great...

Edit... Forgot to add link below

Reverse Flow Smoker... How to calculate build tutorial...

> Reverse Flow Smoker... How to calculate build tutorial... By DaveOmak This is a tutorial and you will need a calculator and paper to note desired dimensions... This tutorial has been proven to make an excellent operating Reverse Flow smoker... Here's to "Alien BBQ" and the folks that first...

www.smokingmeatforums.com

Yes, I did. It is a heat management plate that goes in the cook chamber. the end of it is bent at a ~45 angle and it gets shoehorned in up against the cc/fb wall. The goofy crumpled looking stuff up top is some foil wrap I jammed up there to block some air flow bypassing the plate

I will take a look at the link!

 

[seenred]

First post here but I was over at the smoke ring for a while then drifted away and now see it’s no more so here I am.

Unsure where to stick this since it’s a commercially produced smoker and not a fresh build so hopefully here is alright.

I bought a loaded witchita 12-13 yrs ago and have never been impressed with air movement and cook chamber temp swings. The only thing I changed was added a heat management plate, back then it was an option, not standard. I’ve tried every combination of fire management practices I’ve read about, some better than others but nothing still great in my opinion.

Way back when I remember reading how yoder made the firebox to cooking chamber openings way to big and there was some discussion about closing the gap up, but now when I google search I cannot find any info related to that.

The feldon calculator says the half moon opening should be 11-12” or so. Is there any merit to welding a plate and closing the gap to something close to this size?

And also, mine is old enough to have a welded exhaust stack. Feldon says 25” or so for the 4” pipe. Mine is 18” (I think) when measured from top of cooking chamber. Again, would that be worthwhile to extend?

In the photo, the heat management plate is at top portion of the opening, but it doesn’t completely block off the hole so it would seem that it would not close down the total area of the opening.

Mainly I’m just looking for better and more consistent airflow / draw of this cooker

Thanks in advance!

Hello Adam, and welcome aboard! I've heard for years that folks had air flow issues with those Loaded Wichitas. You may well be on the right track by re-calculating the sizes of your air intakes, your throat opening size (the opening between FB and CC), and your stack height.

I sounds like you already ran those numbers through Felton's calculator. Let me provide you with the link to another pit calculator - the one I've used. I find it easy to use and easy to understand. If you are "mathematically challenged" like I am, this might come in handy LOL.

SmokerBuilder® BBQ Pit Calculator

The SmokerBuilder® Official BBQ Pit Calculator will help you design and build your smoker according SmokerBuilder's proven design calculations. Ensure that your smoker is sized appropriately and save time and money on your build.

bbqpitcalculator.com

At the very least, you might compare the numbers you got from Felton with numbers from this calculator and see if they are close to the same.

Now to your specific questions, if the pit calculators tell you that your throat opening is too large, and your stack is too short, then yes...I do believe there is merit in altering them until they are close to the numbers generated with the calculator.

Good luck! And be sure to keep us posted on how it's going.

Edit: Oh...and one more thing - I really couldn't make sense of the pic of that "heat management plate". Is it supposed to cut down size of the throat opening?

Red

 

[Adamg]

I had a bit of a reply typed out and lost it, so I’ll try to condense this one. The heat plate is an inch or two inside the cook chamber, and not really a tight fit anywhere- so while it may block some air, I don’t really think it cuts down on throat opening area.

According to both calculators my throat opening should be 50sq in. It looks like if I block off half the opening it would put me at approx 58 sq in.

Some pics for clarification. Pic 1 cook chamber with heat plate removed.
Pic 2 firebox side with heat plate removed
Pic 3 heat plate
Pic 4 cook chamber with heat plate installed

 

[JckDanls 07]

I'm thinking if you're going to close that hole up... Do it from the bottom going up.. My thinking is from the top down creates a road block for the heat at the top of the FB... Then put your deflector plate (angled down) inside the CC...

 

[Adamg]

I was actually wondering about that and going to bring that up.

 

[seenred]

Another thought on modifying the throat opening: If I was doing it to my smoker, I'd probably devise a way to do it that was reversible if it didn't work. maybe just tack a plate in there that can be removed if things don't work right. You don't want to weld something in solid and permanent only to realize you got it too small, or in the wrong place. Then once you've experimented, and know you like the results, you can go back and weld something permanent.

I'd probably do the same with the stack - first, try something that can be undone if it's wrong...then when you like the results you can make it permanent.

Red

 

[JckDanls 07]

Looking at the pictures.. I kind of think the firebox is too high up into the cook chamber

 

[Adamg]

Yeah that’s the talks I remember at the smoke ring all those years ago.
I love the heavy build and the look, I just want to get a bit better flow and more even cooks if possible.
I really only get to cook on this one a couple times a year but no two cooks are ever the same and I’m left frustrated feeling like every cook is my first. Wild temp swings from rip roaring fires then adjust the damper 1/8th down and now your smoldering.

I still cook with my fire grate, although the grate I have is much lower than what it looks like is included these days. Mine sits 2” or so off the floor. But after the last several days of watching some YouTube I may try no grate as well

 

[Adamg]

Well, it helps when you search for the right terms I suppose. I didn’t know the opening from firebox to cook chamber was called the throat until now, so this afternoon I googled witchita throat and low and behold found 3 threads on the subject, along with the firebox being mounted too high.

Made it through a good portion of each, no real great fixes

I did pick up a sheet of 22 gauge steel to make a blocker plate, and some 4” duct pipe to extend the stack. I’ll probably start with the stack first and see what that does. Probably won’t have time for another cook for at least a couple weeks, but I’ll be sure to report back when I do.

In the meantime if anyone has any other good input and ideas, I’m still here looking around.

 

[Adamg]

Added section of exhaust to get it to 29”, and took the fb grate out and made my fire on the fb floor.
Exhaust Made mostly no difference in the way it cooked.
I struggled keeping a good fire with no grate, to the point of having a decent coal bed that just kinda snuffed itself out and wouldn’t keep a log lit despite actively shoveling coals around to shake ash off, resulted in my cook chamber tanking down to 140’s until I could blow on the coals long enough to get them heated back up.
Ended up putting the grate back in halfway through and finishing with it.
Pretty miserable cook if you ask me, I spent 6 hrs baby sitting and tinkering every 5 min, but the ribs turned out really good despite that.
Next cook I’ll take out the heat plate, and maybe something else if I think of it

 

[912smoker]

Might have been a struggle but you've got some nice TBS right there !

Keith

 

[Adamg]

Cooked yesterday, I really didn’t change anything from the last. Kept the firebox grate in. Totally different cook from the last. Not sure if it’s a fluke or what.

Was able to keep the fb door closed and the vents pretty much fixed. Nice thin blue from the time I put the log on to time to add another.

For the next time I’ve already removed the heat plate, probably try to choke down the throat a hair.

Which brings me to a question. What affect does an oversized throat have? I understand exhaust and intake, proper draw to pull in air, but I don’t understand what affect the throat has on the overall flow of things

 

[seenred]

Cooked yesterday, I really didn’t change anything from the last. Kept the firebox grate in. Totally different cook from the last. Not sure if it’s a fluke or what.

Was able to keep the fb door closed and the vents pretty much fixed. Nice thin blue from the time I put the log on to time to add another.

For the next time I’ve already removed the heat plate, probably try to choke down the throat a hair.

Which brings me to a question. What affect does an oversized throat have? I understand exhaust and intake, proper draw to pull in air, but I don’t understand what affect the throat has on the overall flow of things

I'm no expert...so this is only a layman's guess on my part, but I think of an offset smoker as kind of a mini wind tunnel. Right or wrong, here's my thinking:

If the throat opening is too small, the air is restricted, and is forced through the opening too fast and with not-enough volume. Think about an air hose. You can force air through a smaller attachment at much higher velocity - but that requires more force - and less air goes out the end.

Just the opposite if the opening is too big. You get less movement of air because there is less velocity and restriction. So my take on that is, you can get the throat opening too big. I assume that's why they include throat opening measurements in the pit calculators.

Not sure if that helps. Again those are just guesses...

Red