CamasM3e93 wrote I'm not a fan of the Harrop whine, I know others love it. I am already making use of the rubber gasket covering the factory airbox outlet. I was at a road race event last month and one of the people there didn't even realize their supercharged Land Rover had the same style blower because the oem design includes a cancellation chamber - no whine. I purchased intake equipment for a Land Rover and a roots blower supercharged c7 corvette. While the c7 design in particular was feasible, use of it would require a smaller than necessary air filter and undermine the bmw factory cold air intake. So creating new problems to address another.
Plan D: Dynamat on the inside of the airbox lid….will put to test this weekend.
Replying to my own post, let the internet explode, lol.
Took the car for a drive to work today and am VERY impressed how well a simple layer of Dynamat on the inside of the factory airbox lid muffles the Harrop supercharger whine. At freeway speeds and hard pulls, it is 95% reduced, so much so that it is hard to hear at all. At neighborhood speeds, I'd say about a 60% reduction. This is a huge improvement and probably makes the difference in my keeping the Harrop kit long term. Really excited about it.
Not so excited that I seem to have a refrigerant leak after my compressor job. The weird thing is that the system held vacuum for 30 minutes after putting it on the vacuum pump but every drop of refrigerant I added went to atmosphere. I assume I've got a pressure relief valve that went faulty for some reason. Will search around for a bit but will probably relent and take it to the shop.