K & N Air filter

gstuart · Apr 20, 2017

after reading this thread i think my head has just exploded, lol

funny u say about the maf, as when my local land rover dealer done a servo upgrade they had left the maf unplugged, didn't even know after a month and was only by chance i noticed it disconnected

now also got my egr valves blanked

some great info here, waaaaaaaayyyyyyyy above my knowledge though

humbled

johnlad · Apr 20, 2017

What I have noticed using live data readings on a de- egr'd td5 is without a properly working maf sensor my injector balance was all over the place, once new maf fitted balance returned to +/-2. So must have some other use than just for egr control

wammers · Apr 20, 2017

johnlad said:
What I have noticed using live data readings on a de- egr'd td5 is without a properly working maf sensor my injector balance was all over the place, once new maf fitted balance returned to +/-2. So must have some other use than just for egr control

IAT possibly. As said earlier if the ECU does not receive expected viable data from all sensors it can become confused.

gstuart · Apr 20, 2017

johnlad said:
What I have noticed using live data readings on a de- egr'd td5 is without a properly working maf sensor my injector balance was all over the place, once new maf fitted balance returned to +/-2. So must have some other use than just for egr control

from what i gather it tells the ecu how much air is coming into the engine and adjusts the fuel accordingly

but i haven't got the expertise like the other guys in here

https://en.m.wikipedia.org/wiki/Mass_flow_sensor

wammers · Apr 20, 2017

gstuart said:
from what i gather it tells the ecu how much air is coming into the engine and adjusts the fuel accordingly

but i haven't got the expertise like the other guys in here

https://en.m.wikipedia.org/wiki/Mass_flow_sensor

On a petrol engine it does, on a diesel it doesn't. Petrol engine MAF sensors measure air flow and the ECU injects petrol to maintain a mixture ratio around 14 to 1. As the throttle is opened and more air flows in fuel is increased to maintain that mixture ratio. Diesel engines do not work like that. There is always more air in the cylinder than is needed for combustion, they are throttle by fuel not by air, as are petrol engines. The more fuel the faster they run, less fuel they slow down. Diesels at idle can have a fuel to air mixture ratio of more than 100 to 1. This reduces as fuel is increased to satisfy power demand and increase engine RPM. The fact that there is always a lot more air than is needed for combustion means the charge burns hotter and produces Nox. So EGR is used to limit the burnable oxygenated air to reduce the production of Nox. Exhaust gas is ingested to reduce oxygenated air content in the charge and the ECU modulates the EGR valve subject to air flow readings from the MAF to try and give the best air fuel mixture ratio it can without producing soot particles. On later EGR versions a much finer control of exhaust gas air mixture is used to try and get as near as possible to an ideal mixture ratio to reduce Nox production to an absolute minimum. Unfortunately this very fine balance can produce soot. That is why modern vehicles made to the latest emissions standards with very finely tuned EGR oxygenated air exhaust gas ratios produce soot and need particles filters to collect it. If these vehicles are run around cities constantly the particle filter can clog and need changing and they cost a bloody fortune. They need to be run at speed with elevated exhaust temperatures every so often to burn the deposits out of them.

gstuart · Apr 20, 2017

wammers said:
On a petrol engine it does, on a diesel it doesn't. Petrol engine MAF sensors measure air flow and the ECU injects petrol to maintain a mixture ratio around 14 to 1. As the throttle is opened and more air flows in fuel is increased to maintain that mixture ratio. Diesel engines do not work like that. There is always more air in the cylinder than is needed for combustion, they are throttle by fuel not by air, as are petrol engines. The more fuel the faster they run, less fuel they slow down. Diesels at idle can have a fuel to air mixture ratio of more than 100 to 1. This reduces as fuel is increased to satisfy power demand and increase engine RPM. The fact that there is always a lot more air than is needed for combustion means the charge burns hotter and produces Nox. So EGR is used to limit the burnable oxygenated air to reduce the production of Nox. Exhaust gas is ingested to reduce oxygenated air content in the charge and the ECU modulates the EGR valve to try and give the best air fuel mixture ratio it can without producing soot particles. On later EGR versions a much finer control of exhaust gas air mixture is used to try and get as near as possible to an ideal mixture ratio to reduce Nox production to an absolute minimum. Unfortunately this very fine balance can produce soot. That is why modern vehicles made to the latest emissions standards with very finely tuned EGR oxygenated air exhaust gas ratios produce soot and need particles filters to collect it. If these vehicles are run around cities constantly the particle filter can clog and need changing and they cost a bloody fortune. They need to be run at speed with elevated exhaust temperatures every so often to burn the deposits out of them.

legend, bless u for that , some fantastic information and extremely informative

SomeJoker · Apr 20, 2017

Information overload for the non mechanics

I had no interest in a k&n filter, just wondering how the thread had got to four pages

and now I know.

discomania · Apr 20, 2017

Catweazle64 said:
Afternoon.

Anyone put a K & N air filter in their TD5 and noticed any improvement in performance?

I'm considering the benefit but despite what K &N state at about £46 not sure if it will do much so looking for any real world experience.

K&N filters are snake oil. Waste of time and generally have lower particle arrestance to the stock filter which is what lets them claim the higher air throughput - they don't mention the additional filth fleeing into your intake system, turbo and engine!

Fit a clean filter more frequently if you believe your TD5 is starved of air and will see benefit...

discomania · Apr 20, 2017

sierrafery said:
...the air flow readings are better than with the paper one and it didn't ruin my MAF nor the engine until now...

Did you ever ask yourself how they achieve this?

Turboman · Apr 20, 2017

discool said:
But it doesn't, you don't have K &N filter then? They still get as black as the paper ones but then u have to fluff about with the clean, it takes me 5mins to replace a paper air filter.

I don't know about today's F1 cars a Moto GP bikes but in my days of paddock tours they didn't have air filters fitted.

Thats a good point about the F1 cars, but of course they rebuild their engines every race, so wear isnt really an issue for them.

As regards the earlier part of your post, the honourable member for Preston has it covered, ^^^^^^^^^^^^^ I shall say no more.
And no, I dont, and never have, had a K&N filter on a landrover. Although I might get one for a performance motorbike for street use, or similar high performance engine.

wammers · Apr 20, 2017

Turboman said:
Thats a good point about the F1 cars, but of course they rebuild their engines every race, so wear isnt really an issue for them.

As regards the earlier part of your post, the honourable member for Preston has it covered, ^^^^^^^^^^^^^ I shall say no more.
And no, I dont, and never have, had a K&N filter on a landrover. Although I might get one for a performance motorbike for street use, or similar high performance engine.

Also i might add that contrary to popular belief the only time any diesel engine ECU and MAF sensor will achieve anything like an ideal stoichiometric fuel/air ratio will be when EGR is active.

Catweazle64 · Apr 21, 2017

This just gets better every day

who could have predicted a simple filter question would be so complex!

But my minds made up.

After considering very carefully all the points raised I can no longer be arsed and will just leave the original one in

that's about as mechanical as I can get.

wammers · Apr 21, 2017

Catweazle64 said:
This just gets better every day who could have predicted a simple filter question would be so complex!

But my minds made up.

After considering very carefully all the points raised I can no longer be arsed and will just leave the original one in that's about as mechanical as I can get.

Good man you know it makes sense.

lynall · Apr 21, 2017

Catweazle64 said:
This just gets better every day who could have predicted a simple filter question would be so complex!

But my minds made up.

After considering very carefully all the points raised I can no longer be arsed and will just leave the original one in that's about as mechanical as I can get.

I like simple so I change my air filter every time i change the oil its so cheap so why not?
From my experience:-
200 disco/defender filter lasted quite well
300 disco got as dirty as can be so quick was silly
TD5 not to bad
D3 sometimes wonder why I change it as still looks mint.
Best of all is the oil bath on the series oil stays clean for an age.

slither22 · Apr 22, 2017

I always put them in my cars well worth the money makes sure it's the panel filter not the induction one.its almost fit and forget although I make sure the filter box is clear when i do my checks also do the egr removal.

cooltide · Apr 23, 2017

discool said:
I don't know about today's F1 cars a Moto GP bikes but in my days of paddock tours they didn't have air filters fitted.

Itg foam filters are used by some f1 teams which is fine as they can stick a new one in whenever the car is in the garage.
Whilst it is a nice piece of marketing for itg, along with btcc, superbikes etc., I think they have a fundamental design floor. A standard panel filter / k&n has a greater surface area due to its zig zag element. pipercross, itg etc. are going to perform comparatively poorly when they get dirty

cooltide · Apr 23, 2017

cooltide · Apr 23, 2017

mikescuba · Apr 23, 2017

Catweazle64 said:
Afternoon.

Anyone put a K & N air filter in their TD5 and noticed any improvement in performance?

I'm considering the benefit but despite what K &N state at about £46 not sure if it will do much so looking for any real world experience.

I'm working from memory here but the person concerned may step in and confirm if I have it correct. One of our group that did a trip to Morocco had one in his 300 TDI. On the return leg of one of his many trips to Morocco the engine blew in Spain. He had it relayed back to the UK. On investigation as to the cause they claim it was due to the K&N filter. Apparently they don't filter the fine dust out which is what caused the engine to blow.

discomania · Apr 24, 2017

mikescuba said:
I'm working from memory here but the person concerned may step in and confirm if I have it correct. One of our group that did a trip to Morocco had one in his 300 TDI. On the return leg of one of his many trips to Morocco the engine blew in Spain. He had it relayed back to the UK. On investigation as to the cause they claim it was due to the K&N filter. Apparently they don't filter the fine dust out which is what caused the engine to blow.

They just don't filter well. They are good at stopping bubble-bee's and stones...

K & N Air filter

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