After installing a K&N filter in the original filterhousing my 04 xjr seems to be a litle more responsive....
Do other memders have the same conclusion?

 

Haven't bought my jag yet, but i use K&N's in both my bikes, and my UrS6.

I concur that there are subtle, but noticeable changes in all of them, including responsiveness, reduced hesitation, and even (proven) HP increases. Not much, admittedly, but it all adds up! 5% on the car, 8% on one of the bikes (VMax).

 

I have used them on my e500 and on my Xjr and I love it

 

On every car forum I have been a member of, there is always some discussion that pops up about the used of K&N or similar filters. No better way to start a controversy. On one side there are those that say the filter does nothing and the oil used can actually be harmful. On the other side there are those that claim increased performance.

For me I had one of these on my previous car for about 15 years and currently have one on my Jaguar. I never bothered actually doing any dyno checks to see the impact (positive or negative) but I have never had any problem using these. I believe a stock filter, when new, will run as free-flowing as the K&N but, over time, the flow with a stock degrades while the K&N does not (unless really really dirty).

Doug

 

Seismic is right. Anybody up for an oil discussion- or maybe use of different octane rating fuels? (ducking for cover)

 

Just don't over oil the filter.

It is my understanding that the problems happen when sopping wet oil flies into the sensors.

I've never had a problem, too many cars to count in my past have used K&Ns

 

Actual tests conducted by ISO show differently...
And I did get tired of two things:
1. clearing the MAF sensor error codes and
2. cleaning the filter every 30 days. (Yes, after 30 days, you actually end up starving the engine as air flow is significantly restricted over factory paper)
FWIW

 

Why every 30 days, are you driving on dirt roads?

Mine looks clean after 3 months

 

to me, mine looked clean... until I cleaned it:-)
Anyhow, I'm only reporting on the highlights of the ISO tests.

Cheers.

 

Here we go, lol!

I think you are being a bit overzealous with the cleaning. K&N recommends a service interval of 25,000 miles.

Per K&N:
4. How often do I need to clean my K&N air filter?

If you have not experienced a decrease in mileage or engine performance, chances are your filter is fine and does not yet need cleaning. To be more specific, the filter does not require cleaning if you can still see the wire screen on the entire air filter regardless of how dirty it may appear. When the screen is no longer visible some place on the filter, it is time to clean it. When used in normal paved road, street or highway conditions, our replacement air filters that fit in the factory air box should require cleaning every 50,000 miles and our large conical filters on an intake system should require cleaning every 100,000 miles. When used in dusty or off-road environments, our filters will require cleaning more often. We recommend that you visually inspect your filter once every 25,000 miles to determine if the screen is still visible.

 

Lol at all you guys claiming noticeable improvements with a K&N drop in. It has been dyno proven that they make 0 hp on a stock XJR and XKR. Maybe 1 or 2 hp, which is in the margin of error. Certainly nothing you will notice. In fact, dyno testing showed no difference with stock paper filter and the filter removed completely.

 

I seem to recall some very diligent testing that some Pontiac TransAm owner did a few years ago with his LT-1. The guy had a base-stock dyno run and then a bunch of dyno runs whenever he would do some mod (e.g., K&N air filter, adjust fuel pressure, replace stock manifolds with headers, install roller rockers, reprogram PCM, install lower temp thermostat, etc.). It was one of the most comprehensive "studies" I have seen as to what gains/losses you would get by doing some mod. Anyway, when it came to the K&N air filter, I believe the most optimistic improvements might have been a couple of horsepower. Certainly nothing you would notice or be able to measure without a dyno. I think the more convincing sales pitch on the K&N was performance over time as the filter got dirty compared with a stock filter.

For me, it is cheap enough to be worth the "feel good" notion that there might be a negligible improvement. Certainly much more bang-for-the-buck versus guys that would spend $thousands on an aftermarket exhaust with not much to show except more noise.

Doug

 

Ditto. Notice I said no improvement on stock XJRs and XKRs. Modified and other cars, maybe, although probably zero improvement on most other stock cars as well.