I'm in the middle of redoing my dust collection pipe. Moving from 7" tape / screws to a 8" Nordfab type of system in prep for my new DC arriving in the next month or so.

Gave the drawing of my shop to the pipe manufacturer have the following issue:

I have a main trunk moving down the middle of the shop with 2 branches. The branches have all of the machines. All of the pipe is 8" except the drops which are 8x6x8 Wye's to 6" & 5" gates.

The pipe manufacturer gave me 2 - "T" sections for the main branches. They are not Wye's like I was expecting, a hard T. I questioned them on the efficiency of the T vs the Wye and they said the T's are very efficient and will not know any difference. The air has to make a sharp 90deg turn to get to the main trunk vs a sloping curve with a Wye.

I'm skeptical... At this point I'd like other recommendations, should I send back the 8x8x8 T's and ask for 8x8x8 Wye's to allow a better slope into the main trunk going to the dust collector or just stick with the 90deg T sections.