Hi,
Just to let people know, and if I did something wrong, please let me know. I decided to install a K&N cone filter on my S80 T6, and found that I had reduced performance. I got a big one, being that i figured it needed as much air as possible to be of any use. I got one that is about 8-9 inches long, and like 4-5 inches in diameter, with a 3 inch flange. With it in I found a considerable loss in acceleration. I monitored my intake air temp with my laptop, and found that it was about 16 degrees F. hotter, than with the factory airbox. I was once told that you lose/gain 1 HP for everyone 10 degrees of air, but it certainly felt like a lot more than a 1.5 HP loss. Plus, I figured that the 1.5 HP loss due to the temp would be made up by the more air, I guess I was wrong. Where the extra air was, I do not know, I did not experience it. I tried to watch the air flow on my laptop, so that I could see which one was letting in more air, but it was too hard while driving. Like I said, if I did something wrong please let me know. Otherwise, I just wanted to let evryone know so that you do not make the same mistake, and waste of money. Well, it was not a total waste because I am going to install it on my girlfriend's Audi A6 2.8 Quattro.
-J.P.

I've avoided K&N filter for this and other reasons for quite some time. Check out this site (http://www.gadgetonline.com/airinduction.htm) and you'll see some actual dyno values with the K&N vs Amsoil Foam/Oil Air Filters. The other reason I dislike K&Ns is because they do a crap job of filtering air. Hold one up to the light and you'll see considerable holes in the paper!!!! Can't imagine that any DIRT might get through these and cause damage!!!!!!

Do yourself a favor - stick with stock paper or even better try out an Amsoil Foam Air filter.


Andrew

Thank you for the post, I definitely will try the amsol.

Did performance come back with the OEM filter? I'm wondering
if any oil from the filter caused problems with the MAF (that
has been reported before).

Also, with my 98 T5 I notice variations in performance day-to-day.
External temperature and humidity seem to affect it the most. I guess
the ECU tries to get as much performance as possible and dials it back
if the engine is running too hot or starts to ping.

Yeah, it did come back as soon as I put it back in. I am much happier with the stock box. My next attempt will be to see how much better, if at all the K&N filter element for the stock air box works. Does anyone have experience with that filter?

Crazy,

I have been using a K&N in the stock box for over 50K miles on an S70 GLT.

There may be a slight throttle response improvement, although most others believe there is no measurable effect.. The intake note is deeper.

The filter must be OILED to work properly. It is the combination of cotton & oil that provides the filtration--much like the early days of motoring. If you use too much oil you may gunk up the MAP sensor.

I've had no problems but I change the oil every 5K and use synthetic.

Bryan

hmm..howdid you mount it..if you just ripped out the stock airbox and bolted it in place then you would have been sucking air out of the engine bay (nice and warm!) which would give you the rise in temp & possible performance drop...

you would need to mount it in an enclosure fed with air from outside the car...that way its breathing cool fresh air...

one other thing to watch here is that is isnt mounted in a low presure or turbulant air stream...basically what your looking for is nice unturbulant cool high density air...

I disconnected the top of the air box, and removed the stock filter element. I then bolted the K&N onto the remaining tubing that has the MAF sensor on it. After that I positioned the filter above the bottom half of the stock airbox so that cold air was being fed in from the stock cold air feed. According to the OBD-II port, and my laptop, the air temp was 16 degrees higher, I did not think that was enough to reduce the performance to the point of what it did.