Hi All,
Has anyone run a K&N high flow air filter in their XK8/R's? What are the pros and cons vs a factory filter?

Thanks,
Karl

 

I run the panel filter in the stock air box. The major plus is that really nice added intake noise when you accelerate. It is that nice intake/valve/mechanical noise that lets you know of the underlying V8 power plant. Seems to go in step with that growl expected from a Jaguar. No difference driving around town though, which is what I want. Added bonus is the extended lifespan I suppose.

The counter point is that it has a reputation of not filtering nearly as well as a paper element, and also possibly affects the air flow in a manner that somehow confuses the air flow meter (the AFM samples the air, it does not measure everything). Last, the proper cleaning of the panel calls for that special red oil. That oil can also somehow coat the AFM and cause issues.

Problem is, with K&N, there is everything and its opposite out there in terms of information.

A cone filter setup was always out of consideration for me as it seems like it would get a lot of warm air from the engine compartment at low speed. This is probably testable, and even the stock setup gets noticeably warmer air when the vehicle is stopped (air temp is available over OBDII).

 

This is my setup,dont no if you can see on this picture but i do have a heat shield with two air intakes from the front and wheel arch, lovely sound on kick down,never seam to have any problems, been set up this way around 7years now

 

Thanks Guys,
I think I will go with the panel type along with my new Mina intake tube it should purr!

Regards,
Karl

 

The corrugations in the intake tube are solely for noise mitigation. Removing these or replacing with an aftermarket tube makes a difference. Jaguar invests in sound mitigation.

It would be interesting to perform a dyno test switching out the different types of air filters. In my experience with another car, there was none worth the change. In the XKR it can be argued that there is not enough filter flow for the upper band. Rectifying these conditions is not by switching panels/filter style, but increasing surface area. The Honda S2000 is an example. It has a huge filter assembly.

It might be a fun project to add a filter housing somewhere in the nose piece. If a unit from a common car could fit, it opens up a lot of possibilities.

 

WhiteHat
I've not run any Dyno-test on my K & N Filters, so I don't know about any additional Power that it might produce....But I sure does sound better than all that waded-up Paper that came in it.....I like it and I change it pretty often....I bought the refreshing Oil but never have used it...I just buy a new one about every 10,000 to 15,000 miles.
I've use a K&N in all three of my XKR's...couldn't ever see anything wrong with it! I still have the Jaguar Breather-Tube as it is set up to breath outside Air and the Air Box also has an additional Breather opening in Front which also breathes cold AIR! If you can find Cold Air in Texas!
Why go to all the trouble of building an Air-Box in the Grill Area? Jaguar has already got (2) openings into Fresh Air with their well thought out Air Box and Breathing Tube...both of which breath in nice cool Air! There again; if you can find cool air in Texas...Here it is the middle of June and Houston has already broken 100 degrees! Cool, Cool Water!!!

Billy Clyde in Houston

 

Yes Bill, I agree that the additional air port in the air box is great in itself. My idea of a larger air-box or an additional one is to achieve a larger air filter panel total surface area. Even with Jaguar's addition of the high load breather in the XKR, the filter panel is the limiting factor for flow rate. The mitigations using the existing box are to use higher flow rate filter panels, less filtering efficiency or elimination of the filter panel. The K&N falls somewhere into the first two. There is no free lunch with flow rate thru filter media. My working life had an aspect that dealt with this regularly in building, regular and special filtration requirements, HVAC. If one wishes to maintain filtering efficiency (rated particulate capture) but increase flow volume, the only way was to increase filter surface area. In our cars and HVAC this is achieved by panel size. There is no market for it, but one could achieve this in cars with cylindrical filters which give a packaging benefit and other options for creative expansion of surface area. Right now, the cone filters are more about flow. The engineers at Honda understood this when they specified the filter surface area of the S2000 on a car that still would use standard filter panels and had to achieve standard car air-intake particulate reduction for warranty and longevity purposes.

The XKR is limited at the upper band by the panel, no doubt. It is simple math calculating flow rate at RPM and maximum filter panel flow as rated new. Interestingly, the math will predict what one will see on a dyno. Jaguar either determined that they did not have adequate real-estate anywhere to give it a larger panel surface area or did not wish to incur the additional development cost. There could also have been a concern for intake air noise which they allow at the high end anyway where it is not as much of a factor for driver and observers. So this is a long way of saying that if one wishes to achieve factory/design filtering efficiency one must increase filter (panel) surface area. Using something like nothing, window screen, K&N filters is a convenient shortcut.

 

Agree, while l have no particular expertise in filtration l do have eyeballs and also a set of K&N filters for another Jag sitting on a shelf. They are sitting on the shelf rather than fitted because of what l saw. Way too many voids in the filter material for my engines l'm afraid.

 

There is a video where a guy dynos a Subaru Impreza with an old dirty OEM filter, an aftermarket filter and a K&N high volume filter. The K&N produced 4HP more on the dyno. Not much, but with the Mina intake pipe it should be around 7-9HP which is not bad.

 

My 98 XK8 came with a blue K&N type cone filter laying in filter box. It doesn't look very effective and I personally don't like the intake noise. I'm sure Jaguar being somewhat performance oriented spent a lot of research designing a proper size air filter assy.

 

Mr. Terrific,

If your Filter Box is Stock, you would use:
Fram Filter #FFCA8720 $23.00
Hastings Filter HAAF1212 $28.22
K&N Filter K33332190 $73.99
Call: Car Parts.com @1-866-529-0412

BC in Houston

 

Any touted pros to the K&N filters in a street vehicle are negated by the issues associated with piling.

i started using K&N’s in 1970 on dirt tracked motorcycles. In those extremely dusty and high vibration conditions the K&N worked very well. And I’ve installed them on numerous cars and motorcycles as customer’s requests.

But in today’s Computer controlled fuel systems, the K&N oil inevitably will degrade the ability of the numerous sensors to function AS designed.

stick with a high quality paper element and you will be fine, even in dusty conditions. Leave the K&N’s on the racetrack where they belong .

Z

 

Thanks BC. Problem is the previous owner deleted the top part of the filter box.

 

K&N's can cause early MAF sensor failures in some cars due to the filter oil contaminating and eventually ruining the sensor. Don't know if this affects an XK's MAF but is likely since it is a Nippon Denso system that is used on many different manufactures' cars from Japan. Still, I plan on adding one to my XK8 at some point in the future and plan on keeping a spare MAF just in case. I also heard cleaning the MAF with MAF cleaner works for some types of cars suffering from K&N filter oil contamination so that would be worth a try first. If you clean and reoil your K&N, I would be careful not to put more oil on it than absolutely required.

2001 XK8 Coupe w/navigation

 

I fitted a K&N filter to my 2005 X-Type but found that it made the engine run lean at idle and threw P0171 and P074 codes. Put in a stock air filter and the problem went away.

 

side note: I got the Mina aluminum intake tube because my plastic one was broken. Careful installing it, as the top part of the tube isn't flattened like the original one, and may interfere with the hood closing. It did make the intake noise nicer, which I liked. But the fit is frustrating as hell.

 

I once installed a K&N panel filter many years ago when I still took it to the main dealer for servicing. It came back sans K&N with a genuine Jag filter and the "go faster" K&N sticker I'd put on the air box scratched out in disgust



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That falls under phrase " Cheeky *******s"

 

Yes pretty Cheeky. Didn't K&N state all manufacturers warranties remain in effect with their filter or did they stop saying that? The K&N likely ended up on another person's XK8/R on the side. Obviously the person that took it out knew what they were doing as evident by defacing of the sticker. They should have given it back to you at the very least. If you knew about it soon enough, contact the Service manager and respectfully demand your property be returned or respectfully and calmly threaten to never do business with them again. But that is just me.

 

I haven't tried it yet on my XK8 but on other supercharged, turbocharged, and normally aspirated cars I have owned it worked out like this: So, in general, I found no difference with a K&N on supercharged/turbo engines. All of my supercharged engines would easily run at full boost (governed by the supercharger) with either filter. So in theory, the engine would be making the same horsepower and limited by the boost setting in the supercharger. One could argue there would be a slight increase in parasitic drag from the supercharger working against a slightly higher Vacuum with a paper filter but that would likely be small. On normally aspirated engines I usually can detect a small gain in most instances. Having not tried it on an XKR I can't absolutely be sure that holds true for an XKR. It all gets down to if the supercharger is barely able to keep up then a lower intake restriction would help otherwise it doesn't matter much.

Normally aspirated engines benefit the most from a K&N because without the aid of a mechanical pump they are more sensitive to small intake restrictions. The same for exhaust systems as well. You need to do both the intake and exhaust systems together to get the most benefit. Don't get me wrong, supercharged engines do benefit from a better exhaust system as well and that would probably be the best place to start on those.

The con is oil from the K&N is known to damage MAF (Mass Air Flow) sensors. Based on my assumption of no to little gain on a supercharged engine, you get all the risk of a damaged MAF sensor with potentially no increase in power. Probably worth the risk on a normally aspirated XK8 due to a slight performance increase. It's just an owners judgment call on that one.