I'll add a bit of input here.
Typically the air intakes are 3/4" ID not 1". The original drilled hole is a 1" hole meant to accept a 3/4 pipe nipple.
Norco somehow or other came up with the 3ea 3/4" holes and that size and number of holes has pretty much been accepted as standard procedure. I have the Norco style holes on mine and I can get my heat up to 325 with a 10" diffuser plate with only 2 holes wide open. With the third hole open I imagine I could go as high as 350 or more.
Anyway, Norco also claims and others agree that 8ea 1/2" holes are sufficient for the top exhaust. I haven't done the math but I'd guess the 8ea 1/2" holes are a comparable or a larger surface area than 3ea 3/4" holes.
I do know that one Weber vent has 4ea 7/8" holes. I did the math on this and I know the 4ea 7/8" holes is a larger surface area than Norco's suggested 8ea 1/2" holes.
So to sum this up, if you think more/bigger exhaust is going to improve your smoking I don't think it will. But it may create a more even heat disbursement and reduce any hot spot you may have below the one vent wheel. Part of Norco's reasoning for the 8ea 1/2" holes was to spread out the heat exhaust, lessening the potential for hot spots caused by the heat exhaust focusing towards one vent.
Hope this makes sense.
Carbon, I could be wrong but I don't think adding more exhaust will raise your heat for chicken. Raising the heat requires more O2 getting on your fire or less diffuser spreading out the heat.
Last edited by pman777; 08-30-2011 at 10:57 PM..