Member Since: 30 Jun 2012
Location: Glasgow
Posts: 46
k&n airfilter poor fuel economy
Just fitted a Kn Airfilter to my disco 3 tdv6 manual.
And my fuel mpg has got terrible its gone from 26MPG to 18MPG why is this the disco has had a fuel remap before a bought it but was running a standard filter.
Just gave it a full service using all LR genuine parts except Kn filter hopeing to gain a little more not get worse
any advice welcome
Thanks LeeD3 Se TDV6 Auto Bonatti Grey
Freelander 2 td4 Xs Black
LandRover Tomcat 5.0wildcat engine 402bhp(At FlyWheel)
TEAMBART
Cross Country Motorsport
25th Nov 2012 11:34 am
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73069
Try fitting the original filter back in to see if it the K&N that is the cause. Could easily be a coincidence, lots to go wrong & rob you of mpg.
PS are those actual mpg or of the trip comp? That relative drop could easily be explained by drop in temperature and garages switching to winter mix. My mpg drops 20% in winter cf summer.
25th Nov 2012 11:37 am
Down&Dirty
Member Since: 17 Aug 2012
Location: Somewhere out back
Posts: 1293
I tried a K&N a while back ran it for a week or so i too had poor mpg/response changed to original and all was good again ,a friend of my had the same problem in a grand cherokee with a K&N, just don't think they suit some engines,
25th Nov 2012 12:16 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
K&N in a D3 is a bad idea, nobody has found it to be a good experience. Stick with the OEM version but change it every year rather than according to the book.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 27 Feb 2010
Location: Surrey
Posts: 2692
I had a K & N in mine for nearly a year,noticed no improvement and on its next service went back to an original filter,actually seemed to run better than with the K & N so i guess this filter did actually make it run worse although i didn't notice the loss in pick up etc until the original type filter went back in
Sticking with original now and replace annually
25th Nov 2012 5:36 pm
Discoed
Member Since: 16 Jun 2010
Location: Yorkshire
Posts: 1020
I too ran an K&N for a year or two - changed back to OEM and seems to be more responsive. Also worth being of a thread on here related to air flow meter contamination from K&N oil.
25th Nov 2012 6:22 pm
Moo D3 Decade
Member Since: 13 Aug 2010
Location: UK
Posts: 14371
Had K&N filter. Rubbish, now gone back to paper.
25th Nov 2012 8:28 pm
The Transformer
Member Since: 22 Jan 2010
Location: Leicestershire
Posts: 1791
If you want to use a performance filter go for an ITG, no oily mess.
We had one on our D3 and it worked well.
25th Nov 2012 9:11 pm
BlackXs
Member Since: 30 Jun 2012
Location: Glasgow
Posts: 46
Thanks for info guys changed to a Gen LR filter last nite so will see over the next few days hope this solves the problem
D3 Se TDV6 Auto Bonatti Grey
Freelander 2 td4 Xs Black
LandRover Tomcat 5.0wildcat engine 402bhp(At FlyWheel)
TEAMBART
Cross Country Motorsport
26th Nov 2012 6:13 am
Down&Dirty
Member Since: 17 Aug 2012
Location: Somewhere out back
Posts: 1293
BLACKXS, Don't forget to post/let us know how you get on.
26th Nov 2012 7:39 am
BlackXs
Member Since: 30 Jun 2012
Location: Glasgow
Posts: 46
UPDATE
Back to original filter and the mpg is back up to 26mpg
Had to clean airflow with contact cleaner to get rid of oil residue from filter as engine management light came on.. But running perfect now. D3 Se TDV6 Auto Bonatti Grey
Freelander 2 td4 Xs Black
LandRover Tomcat 5.0wildcat engine 402bhp(At FlyWheel)
TEAMBART
Cross Country Motorsport
2nd Dec 2012 10:31 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Thanks for the update as it will help any member that searches for this in the future.
Land Rover - Turning Drivers into Mechanics Since 1948
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why is this the disco has had a fuel remap before a bought it but was running a standard filter.
changed to original and all was good again 
,a friend of my had the same problem in a grand cherokee with a K&N, just don't think they suit some engines,
