Finally had a chance to take my MY out for some long drives over the weekend. Hard to definitively say how much better the HEPA retrofit works but so far so good. The weather wasn’t too harsh (high-upper 80s) but I really couldn’t tell any difference wrt air flow, etc. Basically mirroring what was previously stated:
That’s not to say there is no difference, but it remains to be seen how big of a deal it will be for me. Seems like on auto the vehicle just pushes the blower up until it reaches desired temp, etc. Not sure how BWM would change that. I could be wrong. I also use auto settings and preconditioning as frequently as possible.
If you’re planning to do a video anyway (where you reinstall your old set up) it would be interesting to see if you could measure the fan speed for a before and after HEPA install. Also maybe even test to see if it takes longer to get to a certain desired temperature in auto became of the reduced air movement before and after. I’m not sure what the results would be but it would be intriguing to find out.