Debunking the K&N Myth Why OEM is Better

[*Unkle*]

People who like this sort of thing may find this article interesting

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

Without the endless anecdotal threads on forums about how it made this car faster and that car better, sometimes it nice to have some factual information.

It has always made me wonder, if the claim by the Aftermarket performance filters is so strong, why they don't do these tests in a controlled enviroment and display the evidence.

My K&N filter has been in my car since 10,000 miles and been cleaned once at 45,000, its now on 70,000 miles and i'm thinking of going back to OE and replacing every year. I decided to change to a K&N at 10,000 miles as i didn't believe the 30,00miles extended service intervals was good for a paper element. But as MPG is starting to degrade perhaps an O.E. once a year will be better.

 

[*Unkle*]

Strange 66 views and not a single reply?

Does it burst your bubble on the Performance Filter?

 

[jojo]

Strange 66 views and not a single reply?

Does it burst your bubble on the Performance Filter?

The information is too much to take in from the link you posted above, I think I fell asleep after paragraph two.

For 8L S3 owners anyways, it's common knowledge that the OEM airbox and filter has decent airflow for 300bhp+ as tested by Ess_Three over an after market intake.

 

[*Unkle*]

LOl

Your probably right, Lots of pics and a little conclusion is what everyone wants!

Going back to my OEM, just a pain that the A2 has to be fitted from underneath, so the engine tray needs to come off to do it

 

[Ravi A3]

Learn somting new everyday then. lol

 

[paddy]

I have maintained for years that if there was a filter that increased efficiency then manufacturers would fit it as std simply because when you are spending millions developing an engine to achieve peak fuel consumption and power which might or might not get you into a lower co.2 bracket and give you head line figures that just might make your car more saleable....Your not going to skimp on the cheapest item...

I mean you spend hundreds of pounds on each car to give a precise computer controlled air/fuel mix in any conditions at any revs.....then stick a crap filter on the end of the system ??

In my opinion K&Ns were developed to run with carbs in very dry conditions when fuel consumption and efficiency was not the watch word. i had them on my Ducati in the 70s as an alternative to running open carbs ( bell mouths) but they did clog up and you had to alter the jetting to suit. they never increased performance in fact quite the opposite.

If you are running a dumper truck in Arizona or a diesel generator in Saudi then they work well as a alternative to an open system or a screwed up bundle of wire mesh but in the modern hi tech engine ?? not really.

 

[Dazmo]

I have to disagree, i have an ITG panel filter on mine and did notice a very slight performance increase, it also sounds abit nicer too.

The same can be said for when i had one on my old clio 172, it definatly made a difference, you could clearly see how restrictve the standard OEM paper rubbish actually was.

Oh and paddy as for your comment "I mean you spend hundreds of pounds on each car to give a precise computer controlled air/fuel mix in any conditions at any revs.....then stick a crap filter on the end of the system ??"

I disagree , car manufacturers will save every penny they can and if that means sticking in a crappy paper element instead of a £50 long life element then they will, why do you think they want you to replace it every year? if you had one that did not need replacing for 50k they would'nt make any money out of you.

To save money, on my model audi removed all the engines coverings which i have had to buy seperatly myself, and your only talking about a few quid, times that by a million cars and you have saved alot of money on just a few pieces of plastic.

Also as for the performance side of things, you could also argue... why is it so easy to get so much performance out of the car when the stardard ECU map is so restrictive, a remap really does make a massive difference, so why would'nt the manufacturers do that in the first place.

Two reasons, one is the cost involved and two is that not everyone drives the same.

 

[paddy]

Also as for the performance side of things, you could also argue... why is it so easy to get so much performance out of the car when the stardard ECU map is so restrictive, a remap really does make a massive difference, so why would'nt the manufacturers do that in the first place.

Two reasons, one is the cost involved and two is that not everyone drives the same.

Sorry but the reason your car is not remapped from std is engine life. Like it or not, all these stage 1 and 2, S3's on here will be knackered by 75k miles and that would do a manufacturers reputation no good at all. But... applying your filter logic, maybe thats what they would prefer so you had to keep buying new cars..

As for after market panel filters ? well they may well be as good as paper filters but i was thinking oiled K&N's when i wrote the above. I really dont believe anyone would notice an increase in performance with a after market filter..Lets be generous and say you got 3bhp out of it. Thats just over 1% on you A4 and remember that if there was a restriction on airflow it would be at peak flow/revs, not at say 3000rpm...so you would have to be able to detect a 1% power increase at the red line...even less likely that a std filter would be restrictive at diesel revs...maybe on a petrol lump at 8000+rpm !

 

[ALPINE]

a performance cone filter is only as good as you set it up. positioned in a adequate place, given enough cold air and shielded from the dredded heat soak you will see gains over o/e.

If you bolt a cone filter onto you Maf i would agree that O/E is better as its shielded from the hot air. but as i proved a couple of days ago, i have 135g`s read on vag-com with a custom induction set up. a standard box on a standard 150 bhp a3 will read around the 120`s. I know aye done a test on a rolling road and saw no difference between the 2. 2 difference cars, 2 different enviroments, 2 different numbered results.

I dont think this subject will ever be resolved as its just one of those things! its 50/50. Marmite!

personally i love my induction and the way it makes the car feel and sound.

 

[paddy]

Have to say that sound is not bhp...I fitted a K&N to my VR6 years ago and it sounded great. Initially it was quicker but after a few weeks i changed back to std and that was really noticeabley quicker.. it lost me nearly 20 bhp on the RR. It just felt quicker because of the noise...

 

[ALPINE]

i am aware that the sound is not bhp!! im not 17 and im not driving a saxo!! lol

Im going from the vag-com readings showing a gain of 15 g/s over a stock box. stock box should read 120 ish g/s, mine reads 135 g/s with my induction. shown here. numbers do not lie in my eyes

Personally i cant stand K&N its halfords gear in my eyes.

 

[Watty]

Yes, it's all about the noise........and they probably do reduce the bhp in some instances.
Remap on a diesel = smile = induction on a petrol

 

[paddy]

What ever floats ya boat ;-)

 

[Watty]

Alpine, tell me more about yours mate...........
Is it a custom jobby, as I see there's a special plate after the MAF with a flange connector..
Looks good mate.

 

[Oranoco]

With cone filters it really does seem to make a huge difference when adding the cold air ducting. On the rollers I made 1-3bhp more than with the stock air box. So to be fair I'm pretty happy to accept it's pretty much nnot giving more power but rather not costing me any either and it dooes sound nicer, I haven't found any crap to speak of in the induction hoses and clean the MAF out every few months as a precaution to the oil fouling it (this was a must over the first few weeks it was installed

 

[ALPINE]

Alpine, tell me more about yours mate...........
Is it a custom jobby, as I see there's a special plate after the MAF with a flange connector..
Looks good mate.

yes its a Custom jobbie. the plate under the intake pipe is heat resistant stainless steel mirror polished. it also has some heat deflector stuff on the under side of it. (same stuff found in a oven) i just used a bit of powder coated ali, drilled 2 holes in and attached it to the under side of the heat shield and the maf. Shaping the heat shield was a ar$e but well worth it. i will enclose the filter at some stage but for now it works well in the location its in and the fact it had a big **** battery next to it keepin the heat away!

I have sold a few of these kits to my mk4 mates and they love em! Dont know the make of them but 2 of my pals ran the kits that went down into the wing and claim to like mine better. (and the fact they have no worrys when it rains.)

This is kit mk1 so im sure i can make it better when i shield it from the back of the battery. like so...

if that makes sense...

thanks for the vote of confidence dude.

 

[Turkster]

i know from past cars they do increase the flow of air inwards to make your car breath better, but folk commonly forget 2 other killer factors,
1st is the throttle body, it will only allow so much air through it regardless, so a quick milling to make the hole bigger is a must do for any real upgrader,
2nd is the Zorst, if your zorst will only allow the gasses out at a rate set by audi then your also at a brick wall,

So the flow of all air in, through and out are all as important as each other and unless you tackle all 3, then your about to fall victim of a failed mod


at this point iv just fitted a BMC pannel air filter and will soon be making a my big bore throtle body mod to complement it, the Zorst im still looking at,

 

[*Unkle*]

I would like to see the Manufacturers of these filters just do the ISO tests and print them on the back of the box like this article. So why don't they?

A free flowing air filter is great on an engine you intend on fully rebuilding after each track day, but put into a road car for 10,000 miles - 50,000miles?

This part stuck in my mind in the article
"In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms.
Compared to the AC, the K&N“plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt.

Not sure a nice sound and 3 BHP is really worth it? I really don't think its very easy to even detect a 3BHP increase on a car with 200+HP as its only a 1.5% increase? Wouldn't losing weight or clearing you boot of a sub and amp do more?

 

[Oranoco]

When I rebuilt my RS Fiesta engine with 120k under it's belt, it had a receipt for fitment of the K&N cone at just under 40k miles. The car had covered circa 80k miles with said K&N and upon dismantling we found no sign of any issues whatsoever. In fact bar a set of new shells and piston rings the engine went back together as was and carried on producing 200+bhp for a further 3 years with me and is still doing so 2 years after I sold it on.

I'm happy with the sound, I'm not worried about any change in power as long as it isn't losing me any , which it would seem it doesn't and from my experience of dealing with the many cars I have I am yet to see first hand ANY damage caused to the engine as suggested

 

[jojo]

I've always thought K&N filters are good for classic cars like RS turbo's and Golf Mk 1/2/3 etc., but with modern cars with all it's fancy fuel injection, airflow meters and lambda sensors, they are more worried about a clean burn and efficiency than outright BHP, so OEM filter elements should be more than good enough with all the R&A that goes into modern engines.

 

[*Unkle*]

I think your post is exactly what happens on every car forum, not enough tested facts and plenty of anecdotal evident.

I'm sure your RS was fine (nice car BTW) although i would say that new piston rings isn't entirely "no issues whatsoever", (unless you just wanted to change them) on a car with 120k wear had taken place and while it wasn't necessarily down to the filter, or the atmospheric conditions, or the fuel, or the factory production tolerances, it really just confirms the problem we all have.

Not enough evidence of bench test data, from companies that want us to part with our money for a performance filter.

 

[Oranoco]

I cannot attribute the piston ring wear to anything more sinister than normal wear and tear. 120k on the clocks and 30k of those miles running with an additional 60-70bhp over standard. Built three of these engines now, all of which were running K&N cones. My Fiesta, my Escort and my brotehrs Fiesta. The Escort actually cracked 140k before needing a rebuild but that was down to det eating a piston