I can only speak of my first hand experience, but until I used foil to seal the air leaking around my lid, I could not get it to hold a steady temp. Shutting everything down & plugging the exhaust, it would still burn all but a handful of charcoal in the basket. Once I tried the foil around the drum lip, I was able to stablize temps & snuff out the fire when closing it up. I have since ran a bead of high temp silicone around the lid edge & have even better control.
Jim Sewell -- GBA Master Judge, Contest Rep & GBA Webmaster