Not sure if this has been covered on here before? But thought I ought to share this with you all anyway

I drive a 4.2S/C

On a tip off from a friend I fitted a K & N Air filter (from fleabay about £40) anyway best investment I have made in some time! I was getting around 12mpg around town Now with new K&N I'm getting 15.2 I use sport mode all the time haven't changed my driving style and the car seems more responsive!

Anybody else experienced this? Cheers Laurence.

Are you sure it hasn't just leaned your fuel mixture out? If it has, over time it will just melt your pistons because the engine is running hotter.

errrmm... Ady!! Pls tell me you're just yanking his chain.... How does your filter lean your fuel mixture?!

Okay even if it does... how does that make the pistons so hot that over time it damages the engine??!!

Just do a search on any Land Rover forum for opinions on K&N filters .

Free Flow filters allow more of everything through the mesh........ more air and more fine particles of cylinder destroying debris. The 'Sticky' oil used doesn't do the AFM's any favors either.

No such thing as 'Free Power' when tuning engines. If these filters are so wonderfull ask yourself why don't car makers fit them as standard? Ra-Ro Sport Super Dooper Charged.
Ford F350 Super Duty Prototype.
Ni$$@n Patrol 4.8 Overlander.

I've installed performance air filters on all my cars with superb results. (currently using a K & N like you)

As long as you're not in a dusty environment, the trade off of less filtration for more airflow is just scare mongering TBH.

Have fun Buster... even though I've found Cosworth filters to be better than K&N when it comes to improved torque returns..maybe because they are "dry" filters and flow more I'm not sure. (unfortunately not available for the RRS)

I might give one of these a go ... similar design to the Cosworth.

http://www.firstfour.co.uk/performance-fil...752493.php RRS gone
Audi SQ5...Gone Audi Q7 S-Line 240 3.0TDI Gone
Audi A6 Allroad Sport 270 3.0TDI

Petrol and diesel engines perform a lot different to each other when putting add ons on such as air filters, Busters is petrol yours is diesel, the petrol engine burnes a lot hotter than diesel as you will already know this, its usually the maf sensor that gets contaminated and sends the wrong signal for the mixture hence it melts the pistons over time with no warning. Speaking from experience.

How would this work with your warranty, could LR refuse to pay out for an engine problem due to a performance filter like a K&N being used. 2017 Range Rover Sport Autobiography

The Kergan wrote:

How would this work with your warranty, could LR refuse to pay out for an engine problem due to a performance filter like a K&N being used.

Yes, they will use any excuse to get out of a warranty claim, it all depends on how well you know you dealer, wink wink nudge nudge. Something as big as an engine failure they will get to the cause, the filters don't really make that much of a difference to be honest, maybe 5bhp, and if you can notice that in a 2.5 ton motor then you must be good, you could gain that difference just by not fueling you motor to the brim.

Take care
Engines are designed to run at 14.7 to 1 Air-fuel ratio, known as stoichiometric (stoich) when a lambda sensor is fitted this is circa 14.1 to 1. Anything weaker can melt pistons.
Also Google detination or pre ignition pistons melt etc, some nice photos await you.

Best bet, play safe, it’s simple, check the colour of your plugs.
 In Spain - 2018 F Pace - Frightened away from the Sports due to crank failures
Gone - A couple of RRS, A couple of Disco's. However thinking of another Sport.

Lots of positive experiences with K&N filters on the 4.2 engines being it for RRS or Jaguar (as long as one speaks about the replacement panel filters). Over oiling could be an issue for the MAF, but so far I have not experienced this issue. You wouldn't get into a lean condition so fast, first of all the ECU monitors the mixture during gentle driving “closed loop”, and then adjust the fueling. In the meantime it will also set the long term adjustments for "open loop" driving, so when you floor it. These 4.2 engines are pretty rich already, so there the filter will not make a difference.
My 2 cents. RRS SDV6 HEV Dynamic
XKR 700 BHP with Twin-screw and LSD

avos wrote:

Lots of positive experiences with K&N filters on the 4.2 engines being it for RRS or Jaguar (as long as one speaks about the replacement panel filters). Over oiling could be an issue for the MAF, but so far I have not experienced this issue. You wouldn't get into a lean condition so fast, first of all the ECU monitors the mixture during gentle driving “closed loop”, and then adjust the fueling. In the meantime it will also set the long term adjustments for "open loop" driving, so when you floor it. These 4.2 engines are pretty rich already, so there the filter will not make a difference.
My 2 cents.

I would "normally" agree, however Buster007 is seeing a BIG change in MPG, so beg's the question, why?
As I said earlier, check the colour of his plugs !!! In Spain - 2018 F Pace - Frightened away from the Sports due to crank failures
Gone - A couple of RRS, A couple of Disco's. However thinking of another Sport.

More info would be needed to understand what has happened there (Personally I only compare mpg with thousands of miles and 100 drive cycles at least, and even then it is only an indication…).

Under normal conditions I doubt you could measure a difference in fuel consumption, i.e. if one would have compared a clean paper filter and a K&N one. Of course you do get some extra ponies with the K&N, maybe 2 or 3% max. A dirty paper filter would lower the power output, making the difference between a K&N one and paper filter bigger. RRS SDV6 HEV Dynamic
XKR 700 BHP with Twin-screw and LSD

Someone said to me the K&N filter was only good until it clogged up, even though they say 30,000 miles between cleaning and re-oiling, once they start clogging they clog quickly, then its another £10 on cleaning fluid and oil, which means whilst your doing this and waiting for it to dry from been run under the tap, before you can re-oil your without your car

Now a K&N filter is £40 + £10 a year on cleaner and oil, it can be cheaper to do below

on my FL2 a OEM Paper filter is £8, so since a filter normally clogs/gets dirty in one area, you turn it 180degrees, do this twice and then replace, your car will be breathing clean and safer air than the K&N

hope that make sense

There is so much scare mongering going on here.
There are numerous sensors on your engine that will help stop detonation which could cause the dreaded melted piston failure.

Replacing your filter will not result in melted pistons (on a relatively unmodified car).

However, I do recommend that you use a non oiled air filter element as they can cause MAF issues.
Again though, the MAF is not enough to cause catastrphic engine failure on the SC, as the ECU can detect knock and retards the ignition while it knows the MAF is out of range.

Enjoy your new found MPG and filter (but keep on top of cleaning).

Cheers,

Andy