No K&N Controversy here?

C@lvin · Post by **C@lvin** » 28 Apr 2009, 17:56

I soon need a new air filter for my S70.

Over at a Saab message board I also go to, there are a few vocal opponents to K&N filters. At least one of them is a respected mechanic who specilalizes in Swedish cars.

Their contention is that (at least in the Saab 9-5), the oil from the K&N filter will eventually cause the MAF sensor to fail. But in the mean time, the oil from the filter will cause erroneous MAF readings - making the engine run too rich, leading to an eventual cracked piston.

Several of you guys list K&Ns as a mod on your vehicle. What has been your long term experience? Have you had MAF failures with the filter?

I'd like to use the K&Ns. I have them in my Toyota Previa and Honda Odyssey but, because of what I was reading, I have hesitated using them in any of my other vehicles.

Post by **MadeInJapan** » 28 Apr 2009, 18:12

I use the K&N in all of our vehicles and feel good about them- the main thing is to not over-oil them and only oil the underside. I've had no problems with using them.

Post by **IVIUSTANG** » 28 Apr 2009, 18:14

No problems in 60k so far.

- Jesse

Post by **matthew1** » 28 Apr 2009, 18:15

No problems using a K&N air filter in my 850 T5 since 2001.

Post by **JDS60R** » 28 Apr 2009, 19:13

You can check all of the research they have done on this issue at their website http://www.knfilters.com

To date no MAF sensors that were sent in failed due to the filter oil. In one of their tests they submerse a MAF in K&N filter oil and then take it out and and test it. Results were the same as a new clean one.

K&N does not filter as fine as your stock filter but the combustion environment is a messy one and the burt fuel supplies particles larger than the ones K&N lets pass through.

I would remark that the K&N filter built for the 04-07 S60R has two manufacturing details that are wrong. I have written the company and they have corrected one of the two issues. The unresolved issue is that the filter is held to the R with some worm clamps. Once through a few cycles the K &N slightly gives way and needs to be retightened. They are not offering this instruction.

The first issue is that the filter was being produced under the same number but had 2 sets of dimensions ( off by 6mm) . The smaller dimension caused the filter to crack around the MAF side once the air filter housing was put on and tun through a few heat cycles.

C@lvin · Post by **C@lvin** » 29 Apr 2009, 08:01

Thanks, guys. I guess that would be a big NO as far as any controversy.

I will follow suit on the K&N for my Volvos. I noticed an immediate difference in performance on my Toyota Previa (4 cyl NA 175K) when I first installed the K&N on it., but not so noticable on the Honda Odyssey (6 cyl NA 165K).

I also plan to do the airbox mod and 960 throttle body plate for my S70 that everyone's been talking about.

Any suggestions for sources on K&N Filters? Where is the best deal you've found?

Post by **tjts1** » 29 Apr 2009, 09:42

Whats the points of a K&N air filter? Is there something wrong with the stock Mann or Mahle filter? The stock filter costs less than $10. Nobody has ever shown that there is any performance benefit to a K&N filter in our cars and it doesn't filter as well as a paper filter. Why spend the extra money?
http://www.bobistheoilguy.com/airfilter/airtest1.htm

Post by **JDS60R** » 29 Apr 2009, 10:33

I generally see 5hp at the wheels of an S60R.
It allows easier filling of the cylinders so it lowers the draw of oil from behind the valves and rings.

Take a K&N for your car and a stock filter and try and blow air through them. It will be very clear that the restriction is significantly less.

Yes, I too would love to see a perfectly clean filter paper post driving but you can see that all of them let quite a bit of dust through.

The significant details of drying the filter, weighing it, extracting the dust and sorting it by soze is missing.

If you combustion environment is not effected by wear of anything less 20 microns you can judge which filter is better.

If you had the choice of better flow ( acceleration times of turbo motors are definetly increase with a filter that can match its flow rate) and no damage to your motor it would be an easy choice.

Unfortunately no one has performed this test yet.

I think the K&N example of a million mile truck helps to illustrate the benefits of the filter.

By the way - don't clean you K&N . You can vaccum the fuzzy's off if you see a decrease in mileage. The K&N filtration performance increases significantly once dirty. This is a planned benefit of the filter and cleaning it actually lowers the filtration efficiency.

When I fixed motorcycles for a living we did a post filter test on a dirty and new K&N vs the oem and paper filter replacements. The results were similar to this test with the new K&N having just a bit more pass through.

The dirty K&N ( with a layer of fuzz on the outside) did a far better job than the paper filters.

I was a strong disbeliever in K&N until I spoke with one of their engineers and he advised me of letting the filter get dirty and then testing it. He was right.

I just sold my 1999 Taurus 24 valve (stop laughing) to my friend. It has 100K miles on a K&N that I put in 60 Days after I bought it new (had 7 miles on it) and it has never dropped down in mileage. I'm just saying - try not to clean them so much - they really don't need it and will filter better with some fuzz.

I am just sharing experiences here. Please perform your own tests and draw your own conclusions.

Post by **FlyingVolvo** » 29 Apr 2009, 11:33

You could also use the CRC MAF cleaner every 10,000 miles or so if you want to be safe. I've used the MAF cleaner, it's really easy and quick to use and should get rid of any oil that may accumulate from a K&N filter.

Key points here I think are: do not over-oil the filter, oil and clean it sparingly.

tshac · Post by **tshac** » 29 Apr 2009, 11:34

No problems for me......just make sure it is not over oiled.