With an idea coming from Pizzaddict ( http://www.pizzamaking.com/forum/index.php/topic,25471.msg279647.html#msg279647
), I decided to fool around with the "throat reducer" that Antoine and I had experimented with - might as wellv try to put it to good use.
The original intent was to lower the door height to about 63% of the dome to get better heat up times and top heat. It did not really do much of anything.
But, I decided I could modify it and see if i could turn it into a draft door. A little bit of Reynold's aluminum foil and I was in business!
I was very impressed with the results. First of all, the amount of smoke coming out of the front at startup went to zilch. Everything out of the chimney now. More importantly, the heat up time is much faster. I am still timing things but I would say that the heat up time is somewhere around 50% faster. For example, in the first hour the core temperature (not just the floor) reaches around 330 F when previously it would get to around 225 F. In two hours, I am at around 600 when it was around 400 before.
So, I now await my new draft door with a spark screen. Antoine had a few built and he is painting and tweaking them right now.http://www.pizzamaking.com/forum/index.php/topic,21869.msg285037.html#msg285037
This has really made a performance difference.
Below is a picture of my makeshift one. Funky but functional!