HEPA bag inside Cloth bag - Improve/measure airflow

[rowdy141]

Hello everyone,
I've been converting my Kirbys to use HEPA disposable bags inside the original cloth outer bag.
Cloth bags were pretty-much airtight. Fine fabric, double stitching, felt zipper flap, fine zip...
Now the cloth bags are no longer functioning as a container for dust and dirt, or as filter for any particles the paper bag failed to capture, I wonder why we're allowing the cloth bag to restrict airflow at all?
I presume cloth bags are contributing to back pressure against the paper bag and (more-importantly) the fan? Reducing the machine's performance?
I've never been too concerned with statistics but I'm wondering whether leaving the zipper ajar could potentially improve overall airflow and performance.
I can't detect any differences myself, but say 5%-10% improvement during use wouldn't be noticeable to me. It'd need to be measured.

Does anybody with an Airflow Meter want to measure this for me please to see whether the CFM does actually improve if the cloth bag zipper is left ajar?

 

[lesinutah]

I

Have a video of 561 with a hepa setup. It has no outer bag in the video. If you have a complete seal with the top of the emptor and the fill tube. The seal where the emtor connects to exhaust are air tight your good. Ypu can open the emptor tray with the vacuum on and very little if anything comes out.
The bag doesn't really do much as long as it's a sealed system.