Too hot on firebox end!!

[theoldman]

Brinkman offset horizontal.  I've started modifying accordeing to what I'm reading here, but still not having much luck.  I just smoked to 12# turkeys yesterday (early thanksgiving). They came out pretty good, but I'm not happy with temps in the smoke chamber.  I installed dial thermometers in each end of the smoke chamber lid, just above  grate level, made a lid seal out of hi temp silicone, added a diverter

from just above the firebox inlet angled down under the meat grate.  Following the advice on the minion method from a link I found here, I cut a piece of expanded metal that lays at an angle in the firebox from  grate level to above the damper in the end door to keep the lump from spilling out the damper opening.  I filled the firebox up with lump to the bottom of the smoke box inlet, formed a dish in the center and added

a chimney of hot coals to the center.  My chimney is home made, and about half as tall as the store bought, so I added a second chimney of coals as soon as they were ready.  Heres the problem - when I get the far end of the smoke chamber up to 250, the firebox end thermo indicaes 425.  Th brinkman has two meat grates, and my diverter runs from the firebox to just short of the second grate, so just about half way.

The left end of the first meat grate actually rests on the diverter.  I'm thinking the diverter is acting like a flat top grill, and getting so hot that it is a stove in its own right.  I tried drilling a bunch of 1 1/4 holes in the far end of the diverter - that didn't help. I'm going to try bending the diverter to make it "dive" down sooner and see if that helps.  Any more ideas?  The minion method of placing the charcoal and adjusting the damper seemed to work pretty well, but I just can't get that left end temp down.

 

[DanMcG]

I'm thinking the diverter is acting like a flat top grill, and getting so hot that it is a stove in its own right. 

 I came to the same conclusion a while back and removed the diverter for the last few smokes and just used the far end of the smoker. If you figure it out let me know.

My thought was to somehow  lower the firebox so the heat is entering near the bottom of the smoker along with a full diverter plate with a lot of holes for the smoke. If I ever get the time I'll give it a go.

 

[forluvofsmoke]

Sounds to me like your diverter plate should be removed and a curved plate installed which closely matches the arch of the smoke chamber inlet. If you have a flat plate installed against the smoke chamber inlet which is ramped downward towards the center of the chamber, this will cause more heat to be held at the fire box end. An opening on the edges (front/rear) of the plate will allow some heat to escape towards the front/rear of the grate while allowing the center of the fire box end of the grate to run a bit cooler.

I know the distance between the inlet opening and grate level doesn't allow much room to play with a baffle or tuning plate, but on mine, I added a full length/width tuning plate at inlet level placed tight against the fire box end with a 1" gap on the stack end and drilled 3/16" holes based on oven rack therm readings at grate level. Everywhere I was getting a cooler reading got another couple of holes until all areas were within 10-15* F. I used a turkey fryer burner mounted low inside the sfb for the heat source during tuning. The two main drawbacks to this method of heat control is a large investment of time to get the results I wanted, and a very inefficient smoker which uses huge amounts of fuel (2-3lbs of briquettes per hour while in an area sheltered from the weather). My theory on the reason for this is that my tuning plate design causes such a reduction in the flow of gases through the smoke chamber that a higher rate of thermal loss to atmosphere from the sfb is the result.

The trade-off for me was getting nearly full grate useage (front to back, left to right) for burning twice as much fuel. I got the evenly dispersed heat throughout, but at a huge cost in fuel consumption.

Considering the extreme measures it took to achieve the resulting grate temps versus the increased fuel usage, it's not worth it IMO. If you can get a usable grate space of about 60% and fuel consumption is far less then mine, I would suggest stopping at that, unless you will load the smoker up to capacity on a regular basis.

I guess for me, it eventually came down to just buying a second charcoal smoker for those days when I wanted higher capacity. Having a second rig allows you to run one smoker in the 220-240* range for ribs, brisket, butts, etc, while the other can be running 275* for birds. Here's one thing you may consider as well: if you have birds to smoke, place those in the hotter area and other items where temps are lower.

I have recently removed the tuning plate from my SNP and I'm considering a reverse flow conversion...you may want to do the same and save yourself a lot of headaches.

Good luck, brother!

Eric

 

[sqwib]

Just throwing this out and maybe others can add to this because I am not versed on your actual smoker.

Maybe a reverse flow plate or tuning plates?

Look at this mod by Rivet, post #38

 

[kcbluesnbbq]

If you can get a pan of water that will take up most of the area near the fire box, it will keep that end from getting so hot. The water will absorb the heat, but only get up to the boiling point of the water.

I used to do that on my Brinkman before I made the major overhaul and turned it into a reverse flow.

A link to my overhaul is in my signature.

Probably won't be what you are looking for, but the water trick helped me out a lot.

 

[rjnale]

Did "Mods" to my Char Broil Silver Smoker this summer. Similiar to your design. I would second above comments on tuning plates and change the baffle/diverter design. My baffle isn't angled or sloped. It forces the heat straight down and under adjustable tuning plates. My temps run 15 to 25 degrees  from firebox end to stack end. Did you extend stack to grate level?

Good luck