Have you considerred replacing your air filter with a high performance cotton filter? We stock the BMC air filters for the XC90:<p><A HREF="http://www.vivaperformance.com/catalog/product_info.php?cPath=96_97&products_id=180" TARGET="_blank">http://www.vivaperformance.com...d=180</A><p><IMG SRC="http://www.vivaperformance.com/catalog/images/bmc_337_01t.jpg" BORDER="0">
<p>At the same time of replacing the stock filter with a high performantce one you can also replace the cleaner air with more dirty air. There is no free ride with filtration and a limited surface area. If you must have the performance then they are great. If you want a long engine life, then you might want to stick with paper filters. Cotton filters do not do very well with the smaller particles until they get dirty enough to fill the larger passages.
<B>Are there any dyno numbers available??<p>What is Volvo's response to a Bad MAF sensor due to oil contamination from a cotton/oil filter?</B> <B>What is the cost of a MAF sensor for the XC90? <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/rolleyes.gif" BORDER="0"> </B>
Oiled properly there should be no problems with the MAF. <p>The question is are you willing to allow a slightly higher percentage of very fine particulate to pass your filter for less pressure drop. In some of my vehicles I do. Not yet on the Volvo. <p>The deciding factor in my using K&N's in some of our vehicles, is that we have very clean air here in Seattle, and I consider the tradeoff viable.<p>jack - Enginerd
i just installed a k&n on our xc90 (2.5t) and notice a slight difference, seems less sluggish off the line but i only drive it on weekends so it is hard to say for sure.<p>Like jib says above, the air here is clean, so I am not worried about it. If I were to go on a long trip with dusty drives i would probably swap the paper filter back in, takes <1minute<p>i have heard "oil" issues with other cars and k&ns, mostly in situations were the owner is re-oiling the filters (basically over-oiling them) and then having MAF problems. So despite the "lifetime" value prop, i consider k&ns disposable (they come pre-oiled from the factory). <p>Some other cars have known regularity of MAFS problems (like my bmw) so I dont put k&ns in that car - not worth the extra oomph when i hardly use all the power already.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>jib</b> »</i></TD></TR><TR><TD CLASS="quote">Oiled properly there should be no problems with the MAF. <br>The question is are you willing to allow a slightly higher percentage of very fine particulate to pass your filter for less pressure drop. In some of my vehicles I do. Not yet on the Volvo.</TD></TR></TABLE><p>Nicely put on both fronts, Jack.<br>I've run both K&N as well as BMC in my VW and have had no MAF issues (or engine issues for that matter). I'm at 90k miles currently. It's the over-oiling and putting the filter immediately back in that tends to kill MAF sensors. Also, periodic cleaning of the MAF will also help prevent premature failures.<br>There is a noticeable diff. when installed on turbo'd cars. Not huge, but in conjunction with other mods such as a chip, it's very noticeable. I haven't installed one in the XC90 yet, but once the factory maintenance is up, maybe...
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>doug b</b> »</i></TD></TR><TR><TD CLASS="quote">Some people won't leave well enough alone, for 2 hp. I guess they have nothing better to do.</TD></TR></TABLE><p>some people have nothing better to do than post messages...
What's there to be gained by replacing an air filter?<p>After all, I'm sure Volvo employs a car load of engineers. I would think that they would be aware of the SOTA (state of the art), and use the best air filter possible. No?<p>Could you provide some documentation or a link that 'shows' exactly how much performance is to be gained.<p>Additionally, since this is vechicle is an 'SUV' what kind of performance does one expect?<p>I look forward to your rebuttal.<br>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>doug b</b> »</i></TD></TR><TR><TD CLASS="quote">What's there to be gained by replacing an air filter?<p>After all, I'm sure Volvo employs a car load of engineers. I would think that they would be aware of the SOTA (state of the art), and use the best air filter possible. No?<p>Could you provide some documentation or a link that 'shows' exactly how much performance is to be gained.<p>Additionally, since this is vechicle is an 'SUV' what kind of performance does one expect?<p>I look forward to your rebuttal.<br></TD></TR></TABLE><p>No counter-opinion here. I agree 100%<p>For a relatively "small" 2.5-liter engine, you won't see much of a total flow improvement (volume of air) with a cotton/gauze filter. In fact, I'd argue the additional particulates from the air that the "low flow" filter allows by is actually counterproductive long-term to performance gains.<p>Now, if you had a wide-open exhaust on a 5.0-liter V8... maybe that K&N just may make a difference. But, personally I'd still run paper filters!<p>Oh, there is NO WAY you will feel 2 hp on a 4,544-pound SUV. Every 1000/ft of altitute you gain takes away ~3% of your power (that's more than a 6 hp loss for every 1000/ft gained!) and I don't hear anyone complaining... <p>You want better performance? Get a car.
speak to my a$$ - it feels a little more responsive off the line or when you first press the pedal when you are already rolling <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/wink.gif" BORDER="0"> - not going to win any speed sessions, but ANYTHING more is helpful when passing (my exhaust is more open as well)<p>in terms of longevity i have to believe the paper filter design is for the average climates and zones volvo expects to use the SUV in, so I doubt I am giving on longevity here in the bay area...and even if i am, oh well, its just $<p>and i already have a fast car...
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>doug b</b> »</i></TD></TR><TR><TD CLASS="quote">What's there to be gained by replacing an air filter?<p>After all, I'm sure Volvo employs a car load of engineers. I would think that they would be aware of the SOTA (state of the art), and use the best air filter possible. No?<p></TD></TR></TABLE><p>No. I would not trust Volvo to use the best filter available. They use a serviceable filter that is designed to be disposed. Cost is everything, remember? <p>I have a BMC filter on my R. I bought it strictly because I wanted a washable filter. We live in a new subdivision still under construction, and the thought of changing my filter all the time did not appeal to me. Plus, the R's filters are NOT easy to find. I did not expect any performance gain, and I have not seen anything noticable. <p>
ANY oiled filter will eventually foul or degrade the MAF sensor's sensitivity....I know from first hand experience on 2 Euro vehicles.....no matter how carefully oiled it is from the manufacturer. I have therefore installed my own custom AEM Dryflow oil-free reusable cone filters within the OEM airbox with 12HP+ dyno tested gains...
If you really do get a whopping two (2) more horsepower, it probably occurs so high up on the rpm band that you'll never really see it anyway. I collect Porsches (four as of last count) and the Porsche guys have debated this for years. Funny how it's mostly the young "know-it-alls" with the 944s they can't afford to properly maintain, who are claiming the K&N gives them something they can feel in the seat of their pants, har har, no further comment. <p>These kids are also the ones who buy the cone filters for more power, and install them behind the radiator so they can have the added benefit of hot air going directly into the intake system, har har again.<p>Basically, a fool and his money are soon parted.<p>Here's a relevant thread from one of my encounters with the Porsche guys, and yes, neither Porsche nor Volvo engineers went brain dead when it comes to air filters.<p>================================<p><br>I copied this from one of the threads here, but I'd seen it somewhere else too. So if people are willing to suck in dirt, why not just run with open velocity tubes like the old CAN AM racing days? You know they wanted all the power they could get, and they didn't care if they sucked in anything, as long as it wasn't a pebble. Those engines were torn down after EACH RACE.<p>I looked at your photos again, P, and it's quite apparant the cars have limitations that are far beyond the filter. In other words, the internal ports that direct air to the motor, are far more constrictive than what will go through that big air box on a 944, and the even bigger air box on the 928. Why people are willing to drive around with inferior filtration on expensive machinery is beyond me. <p>Here is that passage that makes so much sense to me:<p><br>"I worked for race teams for years. One Toyota Atlantic teem I worked on the driver thought the car was lossing power from the start of a race to the end. So we did leak down checks when we got new engines in. 3% leak down- New. At the end of a race we checked it again and we got 29% leak down. So we sent the head to get the valves done and checked the leak down when the head returned. 4%- Leak down. At the end of the next race 31%- leak down. So we put three dabs of grease down streem of the air filter. "K&N" The next engine came in with 3%-leak down new. And at the end of the race 32%- leak down and the dabs of greas were full of grit. So we changed the filter to a oiled fome filter. 3%- leak down new and at the end of the next race? 18%-leak down. Better still not good. So we made a new air box and used a Mustang GT stock air filter. 3%-leak down new at the end of the next race? 1%- leak down yes I said "1%". The rings bed in and the engine seals up. We went from changing a engine at 300 miles with 29 to 34% leak down to. Changing the engine at 800 miles with 7% leak down.<p>So the bottom line is. You mite gain a littel more power (1 to 2hp) but it will not last long and befor you know it you will have a LOT less. <br>I work on 944s only and when I tare down a 944 engine that has had a K&N filter the cyclenders have a LOT of scores from dirt that got through the filter. <br>If you dont beleve me do the grease test your self. Take out the filter and put a dab of grease in the air box. Then put your K&N filter in and dive the car for a few weeks and pull the filter out and check the dab of grease. <p>Good Luck Mike F "<p>And now...........drumroll please............because I too feel as though I made the wrong choice one day and bought two K&N filters, before an ex NASA engineer set me straight, this is my response. A photo is worth a thousand words?? I'm back to the stock filters and see NO performance drops at all. Zilch.<p>Since then I've seen the light, and been informed by the likes of some pretty smart guys. I left one K&N in place until I got another replacement, and today I finally did the deed on one of my cars I don't drive all that much. Now it's ready to drive.<p>Here's a Purolater versus a K&N. The Puralator has far greater surface area, and it's "all filter". The K&N is mostly wire frame, and actually (in my humble opinion) has very little actual filter medium. It didn't take long after I held the filter up to the sky, and saw lots of daylight, to understand how they get "better flow" (better flow of dirt, in my opinion).<p>Note the superior surface area on the OEM filter. Better flow through a smaller square footage will not give overall more are than somewhat less flow over a vastly larger surface area.<br><IMG SRC="http://img.photobucket.com/albums/v472/Dogsharks/Porsche/944purlatorversusKN.jpg" BORDER="0"><p><IMG SRC="http://img.photobucket.com/albums/v472/Dogsharks/Porsche/944KNfuneralpire1.jpg" BORDER="0"><p><IMG SRC="http://img.photobucket.com/albums/v472/Dogsharks/Porsche/944KNfuneralpire2.jpg" BORDER="0"><p><IMG SRC="http://img.photobucket.com/albums/v472/Dogsharks/Porsche/944KNfuneralpire4.jpg" BORDER="0"><p><br>Yes, this was a satisfying thing for me. It was also a "learning experience" too. After the K&N was totally torched, guess what? Most of it was still there. It's almost "all wire frame". There isn't much filter medium there, guys, it's all wire armature. I held the dirty filter up to the sun before burning it, and sheesh, I could see right through it. Therefore, I stand on my opinion that the K&N will admit more dirt into my expensive motors than the stock filter would, and since Porsche didn't go brain dead when it came time to size the air box and specifiy the filter, I really see no need (now that I'm older and wiser) to spend more and get less. If you can see through the K&N filter, it doesn't take a rocket scientist to know, driving through a dust cloud near a quarry, or driving on a dusty dirt road, would be putting a LOT of silicon into that motor.<p>The oildown of MAF components is also a VERY REAL issue with these filters too. All that for the "convenience" of WASHING and OILING your own filter, wow, now that's convenience. Why not pick up a replacement one day when you're at the parts counter, and keep it until you need it. Ten minutes later you won't have oil all over the place.<p>Your car, your opinion, your choice, and your money.<p>Mr. P<p>
Mr. P,<p>I've known this and that is why I installed the AEM dryflow oil-free intake which has an initial filtration of 98.4% and 99.4% when dirty.....K&N however has an initial efficiency of 95.8% and 98.4% when dirty.<p>As a performance enthusiast paper just doesn't cut it for me so I DYNO'd my BMW M5 V8 with 2 Dryflow cones within the airboxes VS the OEM paper filters and gained 12HP to the flywheel and those are worthwhile numbers....so my suggestion on your P-cars is to buy a Cold air intake and install this filter..<p><A HREF="http://trucks.aempower.com/press_events_detail.asp?aid=54" TARGET="_blank">http://trucks.aempower.com/pre...id=54</A><p><A HREF="http://trucks.aempower.com/product_intake.asp" TARGET="_blank">http://trucks.aempower.com/product_intake.asp</A>#
People who buy these things swear by them, sometimes blindly.<p>The dyno testing is not a measure of what is appropriate for a street driven SUV, in my humble opinion. Anyone who has done dyno testing knows how totally unreliable it is, and how you can hardly get the same results from one test to another on different days. Changind an air filter isn't going to do much for anyone running a stock street driven vehicle, unless it's a terribly under-engineered vehicle. If there were lots of untapped horsepower out there for "raceboy filters", manufacturers would be doing this very complicated trick. It's basically a way to sell a product, not a heck of a lot more, again, in my opinion.<p>Every time this is debated, I've seen people come out of the woodwork, some pretty rabid, mostly young street racers, and some who are undoubtedly SELLING the products to young street racers. In the end, the dyno measures ultimate power at maximum rpm. How many of us drive our XC90s at wide open dyno throttle settings where we would ever see that additional two horsepower? Probably none. Any measure of additional power you may see with a race car filter in an XC90 won't be able to be felt in normal driving, again, in my opinion. <p>One thing about my opinion, I put my money where my mouth is (after I bought two K&N air filters), and everyone else can do the same. Note, I said "your car, your money, your decision". About the comment regarding the cold air kits, all of my Porsches already have a cold air intake provided by the manufacturer, just like the XC90 does. Here's an example, cold air directly to the big oversized filter box from intakes located before the hot air stream coming off the radiator, appropriate for the fastest car sold in North America in 1983 (1983 928S motor in the photo) Did it go any faster with a $50 K&N air filter (no, lol) <p><IMG SRC="http://img.photobucket.com/albums/v472/Dogsharks/Porsche/cc6c53c0.jpg" BORDER="0"><p>If you have to install a "cold air kit", you're starting with an inferior piece of equipment in the first place. If you're running a highly modified motor and you're looking for every bit of power you can find, or if you're on the track, yes, use a race car filter. For a street driven well engineered vehicle, save your money.<p>What caused me to change the K&N air filter(s) I paid for you ask? Simple........."superior information" and the fact that I was willing to swallow my pride and recognize the fact that it was not doing me any good on the power curve or the dirt factor. <p>respectfully submitted,<p>Mr. P