Hi Gearhound,
I'm more than happy to share with you. See below one example. How old is your IR 2.5? I did hear that at one point that they were a bit under powered, but the newer models have more power. That's just rumor, not sure if that's true.
Edit: Oh sorry my roaster is vented straight...
Tipping maybe to hot of a charge temperature, but a profile would help to see what you're dealing with. Here's a profile that shows I think what Steve is mentioning where BT and ET cross over. I'm using a IR1 and the burner is sealed to some extent but I'm haven't torn it apart to see exactly...
I can't speak to that fact but I have heard rumors that they have increased the size of the burners. I'm impressed how large the burner is on my IR1. The machine appears to be very well built and nicely finished. No complaints so far just some minor tweaks (with a bouncy manometer) and...