Double heat diffuser/baffle question

[orcagriffin1]

I have an ugly drum and it came with two diffusers, same slot holes on each and it suppose to double up on each other so that the bottom one sits on the basket, the second one sits on top the first. This way you can adjust the top diffuser to allow % of air to come through and disperse.

My question is when to put it on. I've been getting the basket going, when a nice softball size white coal is going I am adding the plates, closing the lid and letting it go 30 minutes before adding food.

Cooking ribs, it sits perfect at 235 for 5 hours. After that though it starts to dipping temps quite a bit. So I'm not sure to let the basket catch more before adding the plates or not. I love that it holds a low temp like 235-250, but if I cook shoulder on it, it's only cooking some of the time because of the drop.

Suggestions?

 

[ebijack]

Welcome aboard!
I'm not sure why you would want to use 2 diffusers. Not for any reason I can think off. Make sure your diffuser isn't sitting directly on top of your coals.
Mine sits on a grate, just above the coals.
Diffusers are used mostly for stopping/keeping some of the grease from hitting the coals. If you load the UDS with fatty meat. Sometimes you end up with white smoke from so much grease dripping. The diffuser helps.
If you don't want the grease to hit the coals. Use a foiled lined drip pan. To catch the drippings. Do not allow the foil to touch the bottom of the foil pan. As then the drippings will not burn.
Your temp drop is not enough air flow to maintain the temp you are wanting.
Could be not enough exh. Along with not enough intake.
Need more info to determine.

 

[orcagriffin1]

My diffuser is the size of your grate so it sits on the bolts. The 2nd one is suppose to go directly on top of the other and you play around with the hole openings to create temp control (kind of like the top of a weber bullet, the lid itself would be the first diffuser and the chrome plate acts a way to dial things in - just trying to create a visual).

 

[ebijack]

Your trying to control the temp using the diffuser. Don't.
The diffuser is for stopping some of the drippings from hitting the coals. Not for setting temp. And for stopping flames from burning your meat. As when cooking heavy fat/greasy meats. That can cause flare ups.
You always use your intake and sometimes your exh to adjust/dial in temps.
You can absolutely cook without the diffuser. I'd recommend you try running without the diffuser. If the flavor of fat dripping on the coals is not what you like. Then use a foil covered drip pan. Do NOT allow the foil to touch the bottom of the foil pan. If it does, the fat can burn and give off a bad taste.
Then you have the option to add the diffuser for some cooks when wanted. But not for temp control.