Is it concievable to replace the stock cabin air blower fan in a Fiesta (mine is 2012) with one with, say 2x the air flow rating, borrowed from a bigger vehicle, or a better rated one? I have really bad asthma and allergies, and the stock pollen filter in the Fiesta is a joke. So I am thinking to interface a HEPA+Carbon filter with the cabin air vents. This will cut the flow at least 2x (based on experience), so I would need to boost the fan power as well. They do sell in-cabin HEPA filters which plug into the cigarete lighter, but these do not work for my purpose as they do not pressurize the cabin and do not function at the air supply.

58 minutes ago, runcyclexcski said:

Is it concievable to replace the stock cabin air blower fan in a Fiesta...

What you're after is a bit of old fashioned car customisation. It's unlikely that anyone here had actually done anything like this. Anything can be done with a car, at a price! I would suggest your 1st port of call would be to a decent local auto spark and see what they suggest.Firstly in feasibility, then price...

2 hours ago, runcyclexcski said:

Is it concievable to replace the stock cabin air blower fan in a Fiesta (mine is 2012) with one with, say 2x the air flow rating, borrowed from a bigger vehicle, or a better rated one?

NASA have had similar problems with filters in the past. They fixed it with a roll of duct tape !!!

2 minutes ago, unofix said:

NASA have had similar problems with filters in the past. They fixed it with a roll of duct tape !!!

Didn't they also have to convert a square filter to a round one? Though admittedly, Apollo 13s cabin filter was much easier accessed than a  Focus Mk2 🤣

4 hours ago, runcyclexcski said:

Is it concievable to replace the stock cabin air blower fan in a Fiesta (mine is 2012) with one with, say 2x the air flow rating, borrowed from a bigger vehicle, or a better rated one? I have really bad asthma and allergies, and the stock pollen filter in the Fiesta is a joke. So I am thinking to interface a HEPA+Carbon filter with the cabin air vents. This will cut the flow at least 2x (based on experience), so I would need to boost the fan power as well. They do sell in-cabin HEPA filters which plug into the cigarete lighter, but these do not work for my purpose as they do not pressurize the cabin and do not function at the air supply.

I've no idea about any of the items on Amazon https://www.amazon.co.uk/car-air-purifier/s?k=car+air+purifier but there appears to be a few products for a few quid that might be worth the risk buying and using via USB (or whatever charge method they use) than trying to bespoke wire in bigger/non-spec fans into the car.

You could probably also get your money back via Amazon if whatever you order is junk.

10 hours ago, Zico said:

You could probably also get your money back via Amazon if whatever you order is junk.

Junk?? From Amazon?? Never... 🤣

Thank you, all. Re: amazon units: these standalone filters are not going to make a difference in terms of CFM, motor power, filter capacity, non-pressurized design etc. This is based on my experience with clean room design and HEPA/carbon filtration for the pharma and optics industry.

Upon checking youtube videos on folks replacing burned out blower motors in their fiestas (from various years), I learned that the motors are fit very tigthtly, and are quite a bit of pain to get to. It further appears that the motor+blower unit is a piece of molded plastic with the motor tightly nested inside. I could order a replacement standard unit and play with it, but it looked unlikely I can replace the motor, w/o 3d printing the whole unit. I could possibly double the voltage on the standard one 🙂 and keep my fingers crossed, but I do not like this idea (the motor would be running non-stop, which is how I run my current one, and at 24V this won't last long).

A brute-force approach might be to make a self-contained filter can (which I've made many for home and for work) with a built-in blower of the correct specs, and clamp it on the passenger side, right on the hood. Inject the output of this into the two intakes under the windshield via a 3D printed adapter. The can could pass for a some kind of a super-charger/booster if I get correct stickers and/or paint it red. Remove it before passing the MOT. Well, I voiced this idea to my wife and she did not approve of it.

43 minutes ago, runcyclexcski said:

 I voiced this idea to my wife and she did not approve of it.

Wise woman, she's a keeper...