To K&N or not to K&N that is the question - The Unofficial BMW M5 Messageboard (m5board.com)

ihor · 9th March 2009, 16:47

the title says it all... does the K&N filter improve MPG? Does it ruin your mafs? is it worth it? ive done the searching but come up still with two sides to it and im just trying to find out for myself.... any feedback on the issue would be accepted..

timmay77 · 9th March 2009, 16:58

My car has K&N filters in it, but they were there when I bought it. I had no idea there was an issue....

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gsfent · 9th March 2009, 17:52

Quote:

Originally Posted by ihor

the title says it all... does the K&N filter improve MPG? Does it ruin your mafs? is it worth it? ive done the searching but come up still with two sides to it and im just trying to find out for myself.... any feedback on the issue would be accepted..

Various opinions, but I note that Dinan uses K&N for his CAI.

If you are going to use K&N, oil it and then let it sit for a day or two to make sure any/all excess oil has evaporated. Most folks over oil.

It seems if you don't allow them to thoroughly dry, oil used to impregnate the filter can get past and foul the MAF's.

Regards,
Jerry

ihor · 9th March 2009, 20:11

i would buy em and stick em in without putting extra oil on it... but does it do anything say as in mpg or is it just there for cleaner air cause mostly what i researched was people just change oem air filters every oil change

DouglasABaker · 9th March 2009, 20:13

K&N's rely on the oil to filter out some of the particulate - I wouldn't use them without it. Then again, given the number of MAF foulings, I wouldn't use them with it, either...

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sshhh · 10th March 2009, 03:30

ive had it for 1000 plus kms so far so good!

xotickiller · 10th March 2009, 03:40

I would prefer BMC.

Next on my list...

V8 empowered · 10th March 2009, 03:45

I've often considered this too. I dont think the miniscule gains in HP or MPG would justify risking your MAFs being fouled. Actually I dont think the high price of the K&N filters justifies the tiny *supposed* increases in power or economy personally.. And I've used K&N in every vehicle I've owned, right up to when I bought the 535. I like the OEM paper german filters- they're robust & do a fine job. Why bother changing to something else? Just keep renewing the OEM filters every few thousand miles, and you wont have any filter-fouling-MAF issues at all.

And to the people that run K&N filters, thats ok too- you obviously arent over-oiling them, if they work ok. But I'm sticking to the OEM paper type until someone can prove there's a really good reason to use K&N

ihor · 10th March 2009, 04:03

ok so it seems that i will just change the oem filters every oil change and not risk fouling the mafs and since there is no real "huge" gains which i wasnt expecting really but thanks guys

DouglasABaker · 10th March 2009, 19:20

Quote:

Originally Posted by ihor

ok so it seems that i will just change the oem filters every oil change and not risk fouling the mafs and since there is no real "huge" gains which i wasnt expecting really but thanks guys

Unless you are changing your oil every 25K changing the filters every oil change is just throwing money away.

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