[Raakhuga]

Hey guys I have a 2009 E91 318D and I'm going to install this kit : https://www.knfilters.com/57-0680-pe...-intake-system
Into my car, I was wondering if anybody has experience with this kit or a similar kit and if it adds any HP at all

[colorado.e9x]

I suppose you'd like it if you're going for induction noise and heat soaked air lol. My 2¢ is get a K&N drop in and delete the charcoal filter

[Efthreeoh]

I used to run K&N in all my vehicles because it was cool and I was in my 30's. There is no benefit to use a K&N filter. I never noticed any improvement in performance be it power or fuel consumption reductions. I record all my fuel fill ups, so I have data to back up my claim.

My 2 Cents.

[Raakhuga]

Originally Posted by colorado.e9x

I suppose you'd like it if you're going for induction noise and heat soaked air lol. My 2¢ is get a K&N drop in and delete the charcoal filter

Allright thanks for the input man haha

[freakystyly]

From a practicality standpoint, the K&N filters are washable and re-usable, it may need to be done more often than a paper filter, I'm not sure.

I can't recommend an exposed filter setup tho, and I can't speak for performance gains on a diesel.

[Efthreeoh]

Originally Posted by freakystyly

From a practicality standpoint, the K&N filters are washable and re-usable, it may need to be done more often than a paper filter, I'm not sure.

I can't recommend an exposed filter setup tho, and I can't speak for performance gains on a diesel.

K&N recommends NOT cleaning the filter at intervals less than 50,000 miles unless the vehicle is operated in very dusty conditions (i.e. desert racing). K&N's literature states the filter improves the filtering process as it ages and becomes soiled (think about that...). There is risk of damaging the filter if not cleaned correctly using K&N's directions for cleaning and oiling. The filter can be over-oiled and damage down-stream sensors.

I found no measured increase in performance. Cleaning is a PIA and time consuming; you have to wait for the cotton substrate to completely dry before the filter can be re-oiled. There is risk of under-oiling the filter or over-oiling the filter. It's much easier to just drop in a new OE/OEM filter, which takes just a few minutes, and be on your way. Other than it being "cool" to clean your own filter, there is no significant performance gain in horsepower or fuel mileage, so it's not worth the time, risk, and PIA to use a reusable filter.

Two personal experiences... On my E90 I errantly left the OE airfilter in the intake between 195,570 - 267,080 miles (71,510 miles). I keep strict fuel use records. Never noticed a statistical change in fuel consumption. On my Z4, I bought it from CarMax at 23,000 miles. At 34,000 miles I replaced the airfilter and found the airbox literally half full of an old mouse nest. There were bits of newspaper in the nest material. Inspecting a few pieces I discovered they were from Columbus, Ohio, where the original owner lived (I found the car on line at CarMax in Columbus). So besides CarMax's bullshit 100-point inspection crap, I never detected the Z4 had an intake issue (because it didn't). The car ran just as good after I installed the fresh filter.

From K&N's website:
"HOW OFTEN SHOULD I CHANGE MY CAR AIR FILTER?
Under normal highway driving conditions, your car’s air filter typically needs to be replaced every 12-15,000 miles*, which is approximately once a year depending on driving habits and conditions. If you commute through high-traffic, high-congestion areas, you might want to replace your filter every 6,000 miles. At that point, you’d need to throw away your used paper filter and purchase a new one. K&N High-Flow Air Filters™ are designed to last for the life of your vehicle, and are protected by a Million-Mile Limited Warranty. With normal use, they can go up to 50,000 miles before a cleaning is needed (the larger conical filters included with K&N intake systems can go up to 100,000 miles between services). Assuming your total engine life is 175,000 miles, and you replace your air filter every 15,000 miles, you would need just one K&N filter versus eleven disposable paper filters, which can translate to a savings for both you and the environment."

*Read any manufacturer's airfilter replacement interval and you'll find most recommend 45,000 miles under normal use (i.e. same as K&N's 50,000-mile cleaning interval). Under dusty conditions more frequently (same ask K&N recommends). It's utter bullshit a conventional OE airfilter needs to be replaced at 15,000-mile intervals.

My 2 cents.

[nsjames]

people with flow benches have proven that paper air filters are more than adequate.
and at a yearly replacement schedule it's a whopping $20, and it ensures that your engine isn't ingesting dirt.

Want to prove it to yourself? Put a dab of grease in the intake tube after you install that KN. Drive for a month. Check the dab of grease.
You'll find it's covered in dirt.
That's what a gauze style filter lets your engine ingest.

[E92William]

Well when I did my oil analysis I had a bit of a high silicone reading which is well dirt. That however was done a while after an ofhg replacement. And I can't really speak for the one that'll be coming after that change because that's when I swapped the 3 stage in and cleaned my kn. But it might be a sign the air filter is indeed letting dirt through. I personally never felt any difference from my charcoal delete and kn but there's dynos to prove it does so I'm back and forth

[nsjames]

put a dab of green marine grease on the inside of the air box snout to the intake.

I bet you find dirt in it next time you service the filter.

[Raakhuga]

Allright all of you thank you very much for the opinions 😄 I'll let you guys know if I put in the filter after all 😋

[E92William]

Oh I'm sure as hell I'll find it dirty lol. Where I moved they're still doing construction so there's a bunch of dust flying around all the time. Just hope it's not doing my engine anything bad lol

[nsjames]

Originally Posted by E92William

Oh I'm sure as hell I'll find it dirty lol. Where I moved they're still doing construction so there's a bunch of dust flying around all the time. Just hope it's not doing my engine anything bad lol

but if you put in a paper filter it won't get dirty.

even in construction.
I've driven in the desert dust with the OE paper filter and the rest of the intake still remains clean.

[david in germany]

Originally Posted by colorado.e9x

I suppose you'd like it if you're going for induction noise and heat soaked air lol. My 2¢ is get a K&N drop in and delete the charcoal filter

Not sure he even has the charcoal filter on his car.

[colorado.e9x]

No clue. But I agree high flow filters offer no true gains. Other than looking prettier in your sealed airbox and induction noise on cold mornings. I was after both so that's my excuse lol.

[Raakhuga]

Originally Posted by david in germany

Not sure he even has the charcoal filter on his car.

Im pretty sure I have a charcoal filter 🤔 it's a diesel after all and EU norms are pretty strict when it comes to carbon emissions standards

[david in germany]

Originally Posted by Raakhuga

Im pretty sure I have a charcoal filter 🤔 it's a diesel after all and EU norms are pretty strict when it comes to carbon emissions standards

Don’t think so.
This is the one he should have.
https://www.ebay.co.uk/itm/192905803238