Product recommendation: K&N air filter for 2.5 Quattro.

[toff]

Hi,

On my 2.5 Quattro (now traded-in) I replaced the factory air filter with a K&N panel filter...

WOW what a difference, the turbo spools up quicker and the power increase in instantly noticeable! You can even hear the subtle whistle of the turbo which is quite nice! (the factory air filter is much thicker which deadens the sound much more).

Yes K&N panel filters are lightly oiled which can lead to a thin coating of oil on the MAF over time (and therefore reduce performance) but my opinion is this:

Hoover-out the airbox, K7N filter and clean the MAF every 6 months and all will be fine!

It takes just 2 minutes to take the MAF out and give it a good shake in a sandwhich bag full of isopropanol (can't spell it! you can buy tins of it in Maplins) then shake it dry and leave in the airing cupboard to dry for an hour).

For £40, it's a no-brainer improvement that's well worthwhile doing!

Al.

[Marco34]

Hi Toff

Sounds like it's really worked for you. Maybe it benefits the 2.5 rather than the 1.9 TDI.

Just a question about the MAF. I'm after cleaning mine but have noticed a rather strange screw head for it? What kind is it? Also can the MAF cleaning fluid be purchased anywhere else? Is it a kind of circuit board cleaner?

Cheers
Marco

[toff]

Hi,

The MAF is held on with security screws. You can get a set of the security screwdriver bits from Maplins (they come in a small green rubber case - £9.99 ish).

You can get a tin of Isopropanol from Maplins too (£9 - £12) it's an alcohol style solvent with no water in it.

It's not the same as circuit board cleaner (don't use that, I think that has a citrus based acid in it!)

Put the MAF sensor (not the whole MAF housing) in a sandwich bag, half immerse it in Isopropanol and shake vigorously (don't let the MAF rattle around in the bag - Seal the sandwich bag, grip the bag and the MAF together and then shake.

Gently use a flattened cotton bud to clean the metal surfaces of the MAF. Shake it dry and give it plenty of time to dry before re-installing.

Hope that helps
Al.

[Marco34]

That helps alot thanks. I'll give it a go when I get the tools.

:beerchug:

[Crasher]

Why don't you just buy a new genuine exchange unit?

[Marco34]

There are no faults with my maf I just thought as I was changing air filter I would give it a clean to be sure!! Is it not worth it?? :confused:

[Crasher]

If it ain't broke, don't fix it! Personally I have never had any success cleaning hot film AMM's whether using brake cleaner or carb cleaner.

[Marco34]

If it ain't broke, don't fix it! Personally I have never had any success cleaning hot film AMM's whether using brake cleaner or carb cleaner.

Good point. But at least if I have issues I know of a possible solution.

[toff]

Hi,

Crasher, I genuinely bow-down to your vast experience :notworthy but.. have you ever tired cleaning with Isopropanol? I know it's less harsh than Carb / Brake cleaner.. but perhaps that's the key?

Macro34, I cleaned my MAF at the same time as swapping my dirty OEM air filter for a brand-new K&N item, so my results lack a "control" factor!

I do have more concrete proof that cleaning your MAF (or AMM as VAG call it) is worth it:

I cleaned the MAF on my S6 (in the same way as described above).
Using Vag Com's measuring blocks, a friend measured the grams of air per second in the prescribed way as I drove (hard acceleration in 3rd gear for a set length of time, if I remember correctly).

We measured before & after the MAF was cleaned. We saw a 19 grams per second increase if I remember correctly (it was a while ago!)

It also stopped oxygen related engine-check codes (left-bank running lean) from appearing. I had nothing to loose, so I did it and was chuffed with the result!

Hope that gives you some food for thought!
Al.

[Marco34]

Cheers Al. It does indeed. I've started another thread re EGR... usual disabling and then reducing it's operation in Vagcom. The turbo seemed to spool though... anyway. The last test I ran with VAGCOM was when the EGR was set to minimum use. VAG say about 900mg/str. Mine was about 1100mg/str. Not sure if that's good or bad.

I've since increased the operation of the EGR so I'm assuming less air will be passing over the MAF. I'm not sure what to do for the best. I think I will give it a go with the cleaning. After 7 years it must benefit from a clean.

Marco

[toff]

Cheers Al. It does indeed. I've started another thread re EGR... usual disabling and then reducing it's operation in Vagcom. The turbo seemed to spool though... anyway. The last test I ran with VAGCOM was when the EGR was set to minimum use. VAG say about 900mg/str. Mine was about 1100mg/str. Not sure if that's good or bad.

I've since increased the operation of the EGR so I'm assuming less air will be passing over the MAF. I'm not sure what to do for the best. I think I will give it a go with the cleaning. After 7 years it must benefit from a clean.

Marco

I have no experience with altering the EGR usage, but all I'd say is that air recirculated from the EGR is surely less oxygen rich than fresh air coming through the MAF!

7 years!!! It will have a thicker lair of oil on it than a chip shop till! I actually thought Audi were supposed to replace them during servicing as a matter of course every few years?

Al.

[Crasher]

Hope that gives you some food for thought!


http://smileys.smileycentral.com/cat/10/10_9_211.gif

[toff]

http://smileys.smileycentral.com/cat/10/10_9_211.gif

Lol, point taken.

Macro34, to be more direct; if you have solid reasoning for thinking your MAF is knackered anyway - give it a clean, you've nothing to loose.

Al.

[Marco34]

http://smileys.smileycentral.com/cat/10/10_9_211.gif

Crasher - are you implying that the MAF either works fine and requires no maintenance or it's not wise to clean? Al seems to have been ok with his?? Do
VAGCOM show it to be functioning ok, so should I just leave well alone. Can they last years without cleaning.. My car is coming up 7 in September :1zhelp:

[Crasher]

I never clean them anymore; it never worked for me so I just don’t bother anymore. I have a simple rule of thumb, if there is a power delivery problem and there are no fault codes, I fit a new genuine exchange AMM from VAG and take it from there. Sometimes I get it wrong, the last time was on my own car
http://smileys.smileycentral.com/cat/10/10_12_9.gif

[toff]

By the way,

I originally got the K&N panel filter in anticipation of getting a remap as suggested by Crasher (cheers for the tip).

It turned out however, that my AKE engine code wasn't compatible with quite a lot of the tuning boxes. The only compatible tuning box my local VAG specialist (Ricci Concept) could offer is a HOPA box.

HOPA reportedly stick to fuel-remapping and don't mess about with the boost.
Apparently the main point of failure for most TDI engines with tuning boxes is the inter-cooler end-tanks "peeling" open at the seams over time!
Supposedly HOPA tuning boxes are less likely to cause this problem, because the OEM boost levels are maintained.

Can somebody explain to me: how is boost "altered" on a turbo'd engine? Are the manifold absolute pressure thresholds changed or something similar?

Cheers
Al.

[Ruairi_Trainor]

CAn sumbody tell wer exactly the MAF sensor is i think mine could be doin with a good clean cars feelin abit sluggish.thanks.

[toff]

CAn sumbody tell wer exactly the MAF sensor is i think mine could be doin with a good clean cars feelin abit sluggish.thanks.


Hi,

It would be helpful if you could put some details about your car ( 2001 1.9 TDI for example) in your signature, it'll help people give you a more specific answer when you ask questions.

Anyhow, here's a photo that shows you where the MAF housing is (in the circle) and the arrow points to where the actual MAF sensor is (it could be on the opposite side if your MAF has been removed before).

http://www.toffweb.com/images/MAF.jpg


PLEASE don't turn this into another "How do I clean my MAF" thread; there are already loads on this forum, here are a few:

http://www.vwaudiforum.co.uk/forum/showthread.php?t=15977

http://www.vwaudiforum.co.uk/forum/showthread.php?t=5264

Hope that helps.
Al.

[Crasher]

Cleaning the AMM is about as useful as cleaning your teeth in improving performance.

[toff]

Cleaning the AMM is about as useful as cleaning your teeth in improving performance.

But surely the AMM (MAF) can't output the correct values if it has several years worth of oily film on it?

I understand that part of AMM (MAF) heats-up to burn off residue (the evaporator plate?), but there are other parts that do end-up with quite a film on them.

Last time I cleaned a MAF, the Isopropanol was surprisingly yellow after use.

Can we change your mind Crasher, or are you 100% certain it's a pointless exercise ;)

Al.

[Crasher]

I had AMM’s fail after cleaning them and this caused me to have to pay for new ones just for trying to do the right thing, all I got was “it was alright until you cleaned it” so I won’t do it anymore. You can clean your AMM if you like as I won’t have to pay for it.

[Marco34]

Well I decided to check mine and it looked like new. I did give it a blast with some cleaner and still no sign of dirt. There was a certain amount of dark lines, like arching on the connectors. I used some silicon insulation on them.

I can't see cleaning the MAF can cause it to fail unless the wrong cleaner was used.

So far the car seems just the same so mine can't have been too bad. At least I know. I don't know how the MAF can get oil deposits on it. I thought only fresh air passed that looking at the setup.