I see them sold on ebay all the time for anything between 20 and 50 dollars. usually a brushed & polished tube, & washable cone filter and couplings. Are they any good/ Do they really deliver the horsepower boost? Interfere with throttle body intake flow or pressure? Do any damage?
Scarlet, Using any of those oiled filters can eventually burn up the mass airflow sensor in the car from oil contamination. The oil sticks to the wire and accumulates dirt (yep, it does get by the filter), causing the wire to overheat and burn out. If you're building a racecar - running the car at
1/4mi increments - then go ahead. If you want a daily driver, the ol' paper filters are the way to go. I'm sure they will have some effect on hp - whether or not it will be noticable depends on the car and the sensitivity of your "butt dyno". Steve Sears 1987 Audi 5kTQ - had a K&N - made the turbo spooling noise louder but no real obvious effect on hp and coated the intake with oil - now the K&N protects my garage shelf from dust (and does that pretty well) 1980 Audi 5k - had a K&N, now has a paper filter (and an oily film on the intake) 1962 and '64 Auto Union DKW Junior deLuxes - metal mesh filter keeps pterodactyls out of the carb
Hop on over to
A fair number of threads on there about The "CAIM" upgrade which is, basically, what I think you are talking about. K&N/Oiled Airfilters don't seem to be a great idea but "force feeding" the airbox with ducted cold air from outside the car definitly seems to provide a benefit for relatively low cost. As I understand it a lot of the engine mapping etc is triggered by the temperature of the air going into the intake - basically the colder you can make it (i.e. by taking air from ouitside the engine bay) the better the thing likes it. You just need to make sure it goes into the correct side of the Airbox - i.e. before the air filter.
rgds
Iain
The biggest concern I have for them is the ones that are ducted to pull air from below the engine, close to the ground. I've seen more than one car (not just Audis) in wet weather suck in some water. In a few cases, it was enough to lock up the engine. One guy was lucky enough that his car just stalled without bending anything.
Peter Smith
As a matter of fact I went and looked at the K & N site and they warn you not to use them in wet weather. The filter has the tendancy to transfer moisture into the engine with all the usual bad results. So I'll pass on this one for now. Too bad there isn't a hood scoop mod to go with it. What was that jap car that had that wild offset hood scoop?
APR engineer told me just to upgrade the air filter to K&N. It doesn't make a differennce with the cold air intakes in the B5 A4. I was looking at getting a APR chip and asked him about it and he told me not to waste my money. To upgrade my exhaust.
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