Hi,

I'm compiling tests on various air filter and so far have tested several OEM ones. My tests start from about 12 months ago and i'm attempting to make them as objective as possible, testing each filter for a period of 3-4 months taking into consideration the time of year, in which case I repeat test them. The airbox is cleaned out each time a new filter is installed. Sounds boring but I have actually discovered some big differences between seemingly normal paper filters across OEM brands.

I'm interested if anyone has recently bought a performance air filter (cotton,foam type) or paper one and has a picture of it taken brand new out of the box before installing and then details after they've had to remove it for cleaning? i.e. after how many miles? and what the surface coverage of dirt is like? as well as where dirt is located top and/or bottom? (this part is important)

I've just stuck in another Mann filter today and will run it for 3 months before changing to a performance one.(i will be buying jetex, k&n,piperX and itg..possibly BMC).

I'm curious as to the results on each type and will be testing each one more than once. It will probably be quite some time by the time it's all tested(perhaps at least another 2 years). I'm not mad or anything just really interested in filtration and how they all perform.

Sadly neither K&n&, piperx,jetex or ITG were willing to comment or answer any of my technical questions, despite numerous phone calls and emails. K&N was the only one that corresponded with me once (in a non technical manner) and suggested I visit their demonstration for which I was willing. I asked them for details and even suggested I visit them directly, but the person I was dealing with hasn't returned my emails so given up with him now. I'm willing to give them the benefit of the doubt regarding their products so will fork out the money and buy them(yes you heard me right buy every performance air filter available for the vRs)

Edited 27 April, 201016 yr by newskoda

*watches tumble weed roll by*

oh come on make a sad geek happy.

IMO you are wasting your time. Driving around for 3 months doesn't make it a fair comparison as the amount and nature of dust is an unknown variable and will be affected by all sorts of things like time of year, location, which way the wind is blowing and so on.

To do this properly it would be necessary to build a test rig that puts known a simulated dust through the system, then it would be possible to get all sorts of data like differential pressure, air flow rates, mass of filter before and after test, minimum particle size captured etc etc. Add a datalogger and you could present some graphs of filter performance over time.

I suspect the reason manufacturers are unwilling to share their own test results is because it is the sort of info that a competitor would jump on and use for commercial advantage. There may be some independent test results around from an institute like MIRA or perhaps somebody's university work, it might be worth contacting a university that runs automotive engineering courses and ask if anyone has already done this.

Edited 28 April, 201016 yr by bnjyn

There is published work generally showing a new paper filter is best. It was mostly done in USA and available on-line, but it could probably do with an update and a 'sensible' assessment. As byjn says, there are so many variables that short term filter changes probably won't tell you much; even if you have access to a lab balance, you still won't know about particle sizes, hardness etc. I've used a Pipercross for nearly 5 years, but clean it every 5K so it never gets dirty enough to show. This makes it economical for me (but it wouldn't be if there were to be labour costs). The recommended OEM change interval is clearly taking the filter past its best and many people here change at 10K. Going back a while there was some concern about how well aftermarket filters fit and whether there was any leakage, so perhaps you could put a grease patch in the outlet from the filter and check its condition after a period.

Too many varibles makes monitoring difficult, temperature, volcanic dust, pollen, servicing schedules and engine discharges (oil) the list is infinite.

Someone driving in Africa, compared to Sweden would not show any remote similarities.

Let us all know your findings in say, a couple of years. LOL

Edited 28 April, 201016 yr by giandougl

I've used a Jetex panel filter in mine with a PD160 inlet - i've done just over 16,000 miles with it in. Its due a clean - i'll get some pics when I pull it out! I've used jetex filters on all my cars - cheap (for an aftermarket cotton filter). Ive used them with drilled airboxes, with std air boxes and smoother airboxes and always found them to be excellent fit and finish!

I've used a Jetex panel filter in mine with a PD160 inlet - i've done just over 16,000 miles with it in. Its due a clean - i'll get some pics when I pull it out! I've used jetex filters on all my cars - cheap (for an aftermarket cotton filter). Ive used them with drilled airboxes, with std air boxes and smoother airboxes and always found them to be excellent fit and finish!

Thanks Andy - much obliged to you.look forward to seeing the outcome of that

Just installed a piper cross filter into my air box what do you want me to look for or tell you?

I was going to look at piper Cross ones with the PD160

Is it good?

Just installed a piper cross filter into my air box what do you want me to look for or tell you?

Hi, thanks for replying. If you are able to let me know what air filter you had in their before(and how many miles it was in there for) you fitted the piperX and what if any differences you have noticed in terms of performance and economy. The next time also you have to clean your piperX which usually owners of performance filters clean every 5k-10k, take a couple of pics of it please on both sides of the filter. Check how it looks also and in particular is there any dirt on the topside of the filter. Let me know also what approximately your ration of motorway to town driving is.

I know my way may not be at all scientific but i hope those sceptical will humor me until i come up with final conclusions. I know there's a lot of variables involved including time of year (thats why i've bought at least two filters of the same OEM brand), area you drive in, but all of driving is to and from work, then every weekend a drive to Southampton and back again. I dont go anywhere else during the week...i'm a sad git really. a very consistent driving pattern and this has not deviated for 5 years.

I was going to look at piper Cross ones with the PD160

Is it good?

The piperX ones are made from open cell foam and are very breatheable to start with. Not sure if they fit so well in the airbox. They do sound nice from what i've heard.Certainly will let more air in but at the expense of filtration.

I think Awesome sell the PiperX filters at a very competitive price. You should pm Sarah if interested.

NEWSKODA I live in cornwall so no motorways most of my driving is town based. Only had the car for about 2 months, brought from mains dealer who serviced it at 50000 miles if they changed the filter then i have just changed it to pipercross, the standerd filter has been in for about 2500 miles, when i took it out to replace had leaves and dirt in the flaps on underside of filter. The pipercross filter dosent seem to fit as well as the standerd one, it was kinda "is that supposed to be like that" moment apart from that, i think the throttle response is slightly better, a slightly deeper tone when on throttle (i think) but fuel ecom, not sure about im in a busy town and doing around 46 mpg, and i like to have some fun. Any thing else i can help you with?

NEWSKODA I live in cornwall so no motorways most of my driving is town based. Only had the car for about 2 months, brought from mains dealer who serviced it at 50000 miles if they changed the filter then i have just changed it to pipercross, the standerd filter has been in for about 2500 miles, when i took it out to replace had leaves and dirt in the flaps on underside of filter. The pipercross filter dosent seem to fit as well as the standerd one, it was kinda "is that supposed to be like that" moment apart from that, i think the throttle response is slightly better, a slightly deeper tone when on throttle (i think) but fuel ecom, not sure about im in a busy town and doing around 46 mpg, and i like to have some fun. Any thing else i can help you with?

Thanks James, thats excellent!

yes thats a common problem with the PiperX as it doesn't fit all that flush.I'll get one myself as keen to compare this to all the others.

Despite Jetex not responding to any of my technical questions i'd thought i'd take the plunge anyway and buy their drop in panel filter. I fitted my brand new jetex air filter today. I was impressed with the way it arrived, neatly boxed up sporting the Jetex logo.My initial impression of the filter was one of surprise when I inspected it. It's a lot shorter in terms of height compared to the paper one and I almost thought for a second they'd sent me the wrong one but no it was indeed the correct dimensions albeit shallower.

the filter is a quite eye catching, dark blue cotton gauze with a fine black mesh honeycombed across it. The surround is black pvc type. As I looked closer at the filter the glamour started to fade slightly. Hold it up to the light and you can see plenty of light coming through(i dont know if this effects filtration but the paper ones are tight) I noticed very small fragments of the black pvc were peeling off slightly.One of which was about 35-40 microns in size (similar to a human hair) Particles even smaller than this (similar to the size of a grain of rice but finer) were seen embedded on the top of the filter. I brushed out these offending particles as didn't want anything getting blown into my engine. Jetex have done a good job of not over-oiling the filter as I ran an absorbent towel over the material and found nothing that could be detrimental to the intake. So in terms of claims that oil can destroy a maf, i don't think this would be the case with the Jetex.

I inserted the filter into the airbox without any problems; a nice snug fit. It looked incredibly sexy in there. Even now i'm thinking about the dark blue cotton and how nice it looked.

Anyway onto the chase....i took my vRS out for a short drive (10 minutes) and then a longer one on the motorway (40 minutes) and apart from a very very slight deeper induction noise at an rpm of 2700 and above, I found no detectable increase in performance nor did I notice anything special about a better mpg or worse for that matter. It did not rev more freely nor did it pull any better. :'(

I'm actually very disappointed because I had hoped it would be the business. So far my opinion is that a performance air filter serves no other purpose but to look nice and if you weigh that up against the cleaning involved,drying time,disposal of dirt/waste oil, cost of cleaning kit and it being not a good a filter as oem, then it's advantages are as thin as tracing paper. I have removed the jetex and put back in my paper air filter.

I will give another brand a go in the next few months.

Edited 2 June, 201016 yr by newskoda

I inserted the filter into the airbox without any problems; a nice snug fit. It looked incredibly sexy in there. Even now i'm thinking about the dark blue cotton and how nice it looked.

Edited 3 June, 201016 yr by Jonny5ive

your dirty mind at work! clearly.

There has been tests done by indipendent firms in the past. I have read the Mini/Metro owners 'Bible' "Tuning the A-series Engine" by David Vizard and he tested both panel and bolt-on filters. I can't remember which ones came out the best.

I changed my dirty paper filter to a K&N filter wilst on a Rolling Road and got a massive 1 BHP more! It may make a difference if you have a bigger intake (PD160), filter then have it remapped.

Edited 3 June, 201016 yr by Jim H

light shining through it

light shining through it

and that proves what exactly?

That is is opaque?

psst - OEM foam filters are to

Edited 9 June, 201016 yr by Thirdtimeluck

and that proves what exactly?

That is is opaque?

psst - OEM foam filters are to

lots of holes=dirt can get through it. I don't think the oil will stop much

Edited 9 June, 201016 yr by newskoda

lots of holes=dirt can get through it. I don't think the oil will stop much

Out of interest what make is that air filter? I've not seen a blue one before.

I've been using a K/N panel filter in my Golf R32 for over 70,000 miles now.

There is a definite increase in high rpm power, not Ferrari levels, but u can feel that the motor is more willing to race around to the red line. or put it another way, the engine feels less asthmatic.

Yes if you hold the filter upto the sky, u'll see lots of holes and sunlight showing through. It can't be good for the engine, intake valves etc. Surely there must be more wear and tear introduced by higher levels of dust particles.

But on the other hand my Golf is still eager to rev into 7000+ rpm everytime I drive it (over 90,000 miles now), so no signs of damage, doesn't use any oil either.

Also whenever I clean and re-oil the k/n, I'll pop the VW paper filter back in (which is brand new), and it always 'feels' a bit more strangled to drive. It probably doesn't actually translate to any REAL power gains, but certainly the top end feel is different each time I revert back to oem filter

Out of interest what make is that air filter? I've not seen a blue one before.

It is made by Jetex

Yes if you hold the filter upto the sky, u'll see lots of holes and sunlight showing through. It can't be good for the engine, intake valves etc. Surely there must be more wear and tear introduced by higher levels of dust particles.

Yes The dirt that the air filter doesn't stop (usually with performance air filters this is anything less than 5 microns and the number goes up over time.Cotton looses some material over time and multi layer foam means the mid layer gets dirt ingressed and cannot be physically cleaned unless you tear it to pieces) ends up in the engine and if the oil filter can't deal with it, it ends up re-cycling itself over and over again in the oil until the person changes their oil. That's why if you have a performance air filter you should really be changing your oil+filter more often than what it says in the service book.

Edited 10 June, 201016 yr by newskoda