Will K&N air filter 33-2485 cause any problems if installed in prius C?

Here's some reading for you.
K&N filters v/s paper filters | PriusChat

 

Complete waste of time and money. And some major car companies have not done warranty work because of after market air filters.

 

1. having tested K&N filters on dozens of cars, icluding 2 Prius, there is an advanytage for those filters only for high reving cars, which the C is not. They do flow more air at less pressure drop but that is only an advantage at rpm generally above 4500. Red line on a Prissy is 5000 rpm. Under that the air flow per square centimeter of filter area is not great enough to be a flow problem.
2. There have been instances where the 'lubricating oil' of K&N filters have fouled the MAF system of cars, especially after a user has cleaned and re-lubed his filter. there are instances where racers have cleaned their filter of that lube and used the=m quite successfully in increasing dyno results which of course involve rpm ranges from 6500 to 9000 rpm on engines from 1300 to 2000 cc displacements.
3. There are many filters available that offer less pressure drop than the OEM filters, including some direct replacement without any lubricants,but unfortunately I don't know of any that offer ones for the Prissy. We have noted previously that some OEM replacement alternates have less dp than OEM's but we haven't checked ones for the Prissy just because we didn't see the need. As long as you replace the air filter at least once a year under normal driving conditions there isn't enough advantage to justify the cost of a K&N intake system. Racing and high performance you bet but Prissy on the street, not that good. If you insist on a bigger filter with at least more area and/or better filter media there are plenty on ebay. And they look cool too.

 

This study was of air filters compared on a Duramax diesel, but it's very interesting how the K&N faired against other manufacturers.
ISO 5011 Duramax Air Filter Test Report - MotoWiki

 

Good test; we got the same results but we did dtermine the filter area so we could determine the length of time before the filter choked enough to double the clean pressure drop. As expected the area contributed as much as the mesh size (the pore opening size). The finer the mesh size the better at filtering particulate but easier to choke the ai flow. Not surpriseingly, there is a difference in the filter area as well as the mesh size (the size of the pore hole through which the air must pass).
If you want to get the same results as the K&N just install a much larger filter. The larger area has much less pressure drop, the greater area results in slower air velocity which improves filtering efficiency, and the larger area takes much longer to increase the pressure drop to the point where horsepower (really torque) is at least 1% loss. And they cost a lot less than K&N's.
The history of why we did the excercise was to 'improve' on showroom stock power in racing. Though we used them extensiively on race casrs, the K&N's were illegal in showroom stock nd pretty obvious to an inspector. It wasn't hard to eplace the stock filter with much coarder media that allowed a small but noticeable gain in power. For racing where rpm is critical it was useful; for the street no, just as their test shows.
I would have liked to see them dtermine the mesh size of the various samples with standard screen testing; if they did I failed to catch it. You can relate it to the filter efficiency of the contaminated air stream just as we did, but in retrospect I wish we had run the test on diassembled screen sections to see just what the media was.

 

Will K&N air filter 33-2485 cause any problems if installed in prius C?

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It actually can, but I'm not sure about the throttle body (TB) and mass air flow sensor (MAFS) setup on the baby Prius.
Sometimes people over-oil the cotton media in the K$N and it FODs out their MAFS, and can lead to your having to clean your throttle body a little earlier than is normal.
Mostly?
They are just a waste of money.
There are some people who will keep their cars for ten years who use oily cotton gauze filters for environmental reasons. I always counter that you have to clean the filters regularly and the re-oil them so that they're contributing to ground water pollution instead of putting a few pieces of paper and plastic into a proper land fill.
If you're one of these people, then be sure you have a plan to deal with that issue.
It is possible, but like many environmental issues you have to think about it a little bit.

You can also theoretically save money if you're one of those same ten-year-per-car people providing that you don't spend money on a cleaning kit every time you have to "kleen" the filter...and provided that you don't have any of the aforementioned MAFS or TB issues.

If it were me?
I'd try to just buy the K&N sticker.
THEY work.

The rest of the stuff is crap.

Good Luck!

 

I've used them, but they are a waste of time/money. The initial cost plus cleaner and lube will always be more expensive than simply replacing paper filters.

As for performance, only on cars that would need them (move lots of air.) The Prius C is not one of those cars.

If you want to play with your new car, keep it cleaned and vacuumed.

 

Stick with the filter recommended for your car.

DBCassidy

 

Good to know even though I dont plan on installing an aftermarket filter