Originally Posted by SmokinJohn
I am assuming you have three intake holes (you didn't say).....
If so, leave the top exhaust vents open (think of them as the exhaust pipe on a car - if you plug them, the exhaust has nowhere to go, and your engine will fizzle), and open all three intake ports.
As your UDS comes within 10-20 degrees of target, close off ONE intake. Watch the temp. When it gets within 5 degrees of target, close the SECOND intake. Watch the temp again. It *should* stay at the desired temp. If not (and this is where ball valves and magnets earn their pay), restrict the air flow to the THIRD intake.
This should put you on track, unless you have a leak. If you do, use foil, gasket rope, a welders blanket, or RTV caulk, depending on where it is.
Many thanks SmokinJohn - I have 2 x 3/4" inlets (with caps) and a 1.5" ball-valve.
So, in terms of exhausts - I should have the 2" open and the 3 x 3/4" exhausts all open too? I got confused because I read about people matching their inlet square-inchage with their exhaust square-inchage! I have 4.25" of exhausts, but only about half that for inlets, of which 1.5" are closed (if I shut the 2 x 3/4" inlets). It kind of makes sense, as I suppose it creates more updraft if the exhaust is greater than the inlet.
Here's the lid showing the exhausts, just so it makes more sense what I am on about