Quote Originally Posted by Andy Giddings View Post
Bob, if you're not getting enough flow at the power tools changing the main line and drops would give you a boost. You don't say whether your main trunk is smooth or not - I assume it is? If so, your boost is not going to be as good as changing out a long flex duct but, according to the static calc spreadsheet mentioned earlier in the thread, still around 8 in wg at 1000CFM. This boost will drop if you've got lower flow. Would certainly recommend changing both line and drops if you have the time/budget. Also go for large radius bends.
Thanks, Andy. I'm getting pretty good flow now, just checking for improvements. My main line is smooth drain PVC. I think I'll try to extend the drops with some PVC to as close to the tools as possible, shorten the lengths of current flex in those areas, and see what happens.