I'd like to start a discussion on what maakes the difference between good BMEP's and not so good BMEP's.
Things we've touched on so far in the other thread:
Effeciency, effeciency, effeciency.
BMEP's ar related to torque
They are calculated like HP
They are a common denominator between all engines.
My thoughts are that they start with a planned out engine combinatioin, before a part is ever purchased. For me, the key is thinking of every part in the engine as they're related to eachother, not as individual parts. That's basic.
I think where good BMEP's start are in the combustion chamber. I had a thread on "what makes an engine accelerate" on HB, and I tried and tried to steer the conversation in this direction. No one ever mentioned BMEP's, or combustion chamber effeciency.
If you have a bunch of mismatched parts, the best cam in the world isn't going to help much, but with a good combinatioin of parts, the right cam will make all the difference. I don't believe there's any "one cam fit's many engines" thinking here. I'm a firm believer in having a cam designed specifically for the application intended. It dosen't cost that much more over all, and the difference can be huge.
A good induction system is huge to BMEP's. Again, the right intake and carb(s) for the application. With carbs, it's the little details. Just about any setup will run, but really getting the carb(s) dialed is a big producer of usable power. If what goes in the chamber isn't right, the combustion will suffer, no matter how good the chamber design and work. Fuel inj. and EFI are other options, but I'm keeping it simple, since most of us are working with carbs.
So, again, I think BMEP's are a direct sign of combustion effeciency. Whatever is related to that, however you can improve that, IMO, will yield improved BMEP numbers across the board. That sounds failry generic...almost duh, but when you start thinking about what effects combustion, it gets a little more interesting.
Those are just a few thoughts, and just a start.