Pit Calculator Guide

[Kcd2016]

Hey fellas,
I've been lurking for a little while now as I have a smoker buildin' idea stuck in my head that I just can't shake.

I'm seeing frequent posts that refer people to the pit calculator from the front page, this calculator is fairly straight forward. My question is there a guide anywhere that explains smoker design calculations *and reasoning* in detail? I'd like to see the equations too. (I'm from an engineering background, I dig 'getting into the meat' of this kind of thing. A smoker design 101 textbook would be perfect! )

Thanks in advance for any help.

[Squiggle]

There are many tried & tested plans available from smokerplans.net which will help you build a wicked smoker & the guys here will give you any info you need to set your inquisitive mind at ease on the workings & thinking behind what works, certainly did with me.

[Kcd2016]

There are many tried & tested plans available from smokerplans.net which will help you build a wicked smoker & the guys here will give you any info you need to set your inquisitive mind at ease on the workings & thinking behind what works, certainly did with me.

I already have my eye on a particular set of drawings and do have many questions, but I think those are of a subject for another thread.

[Squiggle]

Like your new build thread??

[Pete Mazz]

Hey fellas,
I've been lurking for a little while now as I have a smoker buildin' idea stuck in my head that I just can't shake.

I'm seeing frequent posts that refer people to the pit calculator from the front page, this calculator is fairly straight forward. My question is there a guide anywhere that explains smoker design calculations *and reasoning* in detail? I'd like to see the equations too. (I'm from an engineering background, I dig 'getting into the meat' of this kind of thing. A smoker design 101 textbook would be perfect! )

Thanks in advance for any help.

It was all started by a guy with the handle AlienBbq back in 2008. He founded Pitmaster University in 1990 and has been teaching and tweaking since then. His calculations first spawned an Excel spreadsheet and morphed into an online calculator. All the pit calcs, including ours, are based on his.

As far as the equations go, it all starts with the CC size, then the FB size.

Calculate CC volume, Set FB size at ~35% of CC, use at least 4" round stack, use multiple intakes FB volume x .003, throat size = FB x .008 for Throat Calc.

[Kcd2016]

It was all started by a guy with the handle AlienBbq back in 2008. He founded Pitmaster University in 1990 and has been teaching and tweaking since then. His calculations first spawned an Excel spreadsheet and morphed into an online calculator. All the pit calcs, including ours, are based on his.

As far as the equations go, it all starts with the CC size, then the FB size.

Calculate CC volume, Set FB size at ~35% of CC, use at least 4" round stack, use multiple intakes FB volume x .003, throat size = FB x .008 for Throat Calc.

Thanks for the info Pete.

You specified a round stack, is it important that it's round or is opening area what we're after?

Regarding the placement of the stack, what are opinions on the stack placement's elevation IE at grate level, or at the top, etc.?

[Pete Mazz]

Round stacks work more efficiently. A 4" square stack has more area but will move the same amount of air as a 4" round.

Lower placed stacks supposedly yield more even top to bottom temps but are just now becoming popular with builders.

[Kcd2016]

For the smaller CC drawings, like 24" dia x 36" long reverse flow, how hot can you expect to be able run the pit? I'd like to be able to run up to 325F sometimes. And at that temperature how often would I be feeding the fire?

If my 24 dia pit has two levels of grates, what kind of temperature differential would one expect between the upper and lower grates (still reverse flow)?

If I'm wanting to run hot and fast would I be better off non reverse flow?

[Dirtytires]

My pit was built off the plans on this site and is a 48 by 24 pipe for the cook chamber.

I am still adjusting but can get a 40 degree temp swing top to bottom leaving exhaust wide open yet can bring it down to about 15 degrees by working the exhaust damper. Temp swing can be good....I can cook chicken on the top and ribs below, both at perfect temp. Keep in mind, unless you cook for an army, most of you cooking will most likely be on the main\lower grate.

Once up to temp, I feed it a stick every 45 min. Yes, 45 min....I even set an alarm. 40 minutes gets too hot and 50 minutes I loose my fire. Pretty silly but that works for me.

[Kcd2016]

My pit was built off the plans on this site and is a 48 by 24 pipe for the cook chamber.

I am still adjusting but can get a 40 degree temp swing top to bottom leaving exhaust wide open yet can bring it down to about 15 degrees by working the exhaust damper. Temp swing can be good....I can cook chicken on the top and ribs below, both at perfect temp. Keep in mind, unless you cook for an army, most of you cooking will most likely be on the main\lower grate.

Once up to temp, I feed it a stick every 45 min. Yes, 45 min....I even set an alarm. 40 minutes gets too hot and 50 minutes I loose my fire. Pretty silly but that works for me.

What temperature do you typically cook at? And how hot can you sustain temps in your cooker?

[Scooter1]

Im new here an thanks for the add by the way. My question is im building my first reverse flow smoker. Out of an old air compressor tank. Thats 20" X 48". It say by the pit calculator that i need a 10 1/4" half moon openning between FB an CC. But it doesnt say if its high or long.

[Pete Mazz]

Your PM said 22" tank and 14.75" half moon. Try our PitCalc And start a thread in Reverse Flow Smokers.