replacing air filter

Punter · Post by **Punter** » Wed Jul 26, 2017 10:14 am

Is it worth spending £60 on a 'high flow' air filter (K&N)? Do they make a discernible difference? Views/experience welcome, as always.

Smartbear · Post by **Smartbear** » Wed Jul 26, 2017 11:33 am

Punter wrote: ↑Wed Jul 26, 2017 10:14 am Is it worth spending £60 on a 'high flow' air filter (K&N)? Do they make a discernible difference? Views/experience welcome, as always.

Hi, I can hear the turbo a little more on my car but didn't notice anymore shove-I just like the brand

Rob

flybobbie · Post by **flybobbie** » Thu Jul 27, 2017 12:31 am

I have K&N on a 23i.
Seemed to make a slight difference.
Just washed and re-oiled. Could tell when too much oil on it. So washed again.
Also good idea to clean the air mass flow sensor in case any oil gets on that.
Not sure though that an oiled filter is really any good long term.
The dust will just get stuck to the filter, where as at least with paper, the larger particles just might fall to the lowest part of the filter and not block it.

GBZ4 · Post by **GBZ4** » Thu Jul 27, 2017 5:16 am

IMO I'm not sure there is a noticable difference other than audible. The fact that an oiled filter will require regular maintenance, the frequency of which, depends on he environment you drive in really doesn't give sufficient reward.

Ewazix · Post by **Ewazix** » Thu Jul 27, 2017 6:37 am

See previous

viewtopic.php?f=2&t=95477&hilit

bob4333 · Post by **bob4333** » Thu Jul 27, 2017 8:33 am

Tried K&N once on another car and made not a scrap of discernible difference, but very nicely made.

Also tried an oiled foam ITG as part of a rechip / new exhaust set up which gave about +10hp on a dyno IIRC. The ITG on it's own probably wouldn't have contributed much but was more "throatilly" noisy.

But in the end I thought why run the risk of compromising the MAF with risk of oil for such small gains? Went back to standard and got on with just enjoying the car.

I think what we get from BMW and others is a balanced approach to engine performance. It's designed as a complete entity which includes the air delivery system. Aftermarket filter companies make many claims but I'm not sure they amount to much in the real world other than a psychological benefit that "I've got something better". And if that works then why not?

Nictrix · Post by **Nictrix** » Thu Jul 27, 2017 11:43 am

bob4333 wrote: ↑Thu Jul 27, 2017 8:33 am Aftermarket filter companies make many claims but I'm not sure they amount to much in the real world other than a psychological benefit that "I've got something better". And if that works then why not?

Theres no way that any of the aftermarket companies have tried and tested every vehicle to make sure that its operating at its best.
I have K&Ns in our bikes but to be honest if I should have stuck with the manufacturers.
Although they claim to not need cleaned or re-oiled in xxxxxxxxx miles this is just wrong.
I have cleaned the filter in my bike a few times over the 10 years I have owned it and only covered less than 25,000 miles.
The filters do get really dirty and there is no way you could leave it in there without compromising performance.
The hassle of cleaning the filter is not worth it either and I will not buy another K&N for any vehicle.
They are really well made though.

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