SonicA6

Hi,I,ve added a k and n air filter to replace my standard factory one on my petrol 2.0 2002 a6,and the difference is a great little bonus,but can I go a step further and add more to it, like a cold air induction kit?
Any views or advice would be great,as I,m not to sure what I can or can't do?, Thanks in advance!....

mithrilG60

No matter what the K&N ads will try to tell you, the stock air box with a stock paper air filter flows far better than anything the aftermarket has produced.

eejimm

^^^ true - sorry
Plus, the oil on the K&N can/will coat the sensor in the MAF and cause it to report wrong or damage it. The stock CAI / airbox is better than anything you're likely to find at a price you will want to pay, and for the non-turbo engines it doesn't make any difference anyway. I run a stock CAI/airbox/filter on my 2.7t at 18+ PSI and it flows great. There's way more pressure drop in the induction piping than in the air filter (I've measured it).
Jim

SloopJohnB@mac.com

(Edit)...I meant how do you know the K&N flows any better than the stock box? OK, how do you KNOW it flows great? Do you have a FilterMinder on the airbox or some other way of measuring the pressure drop across the box? I once had a FilterMinder on my Saab OG 900T...the BOX/hose was the limiting factor since I had 25+ inches of water pressure differential without the paper filter above 4000 rpm with 21psi boost. In that case a K&N filter with an Amsoil oiled-foam sock helped, but I had to can the OEM box which also had a fresh air intake.

In your case it would pay to KNOW the pressure drop across the stock box before you continue to use the K&N and it fouls your MAP/MAF sensor.

eejimm

^^^ Yup - so true...

You could pick up a used Magnahelix differential pressure gauge on E-bay for $20 and actually test it (like I did on most of my cars). It's amazing how many factory designs are pretty good, or even great.

Although I have head some people say they like the sound of the aftermarket CAIs better. Personally, there's other things I'd like to hear when driving...
Jim

SloopJohnB@mac.com

Yep. To crush your competition, see them falling behind you, and to hear the lamentation of their women.
(With apologies to Conan...)

SloopJohnB@mac.com

About that magnahelix...it's a real-time gauge that doesn't give you the max depression. You have to watch it or have someone else watch it...I like the filterminder because it also tells you when to change your filter.

Unless, of course, you have an $%@#$% air box that is the SOURCE of the restriction! In which case the filterminder will be always telling you to change your air filter!!

NAC5000

Hello! like 2 weeks ago I bought a KN cone filter and yes the sound is GREAT! buut! the thing gets really hot and my ecu threw MAF and IAT error codes!

16497 - Intake Air Temp. Sensor (G42): Signal too High
P0113 - 35-10 - - - Intermittent
16486 - Mass Air Flow Sensor (G70): Signal too Low
P0102 - 35-10 - - - Intermittent

also I felt like the idling was a liiiitle weird, I red a lot of post about the mafs failing with kns so I decided to better return it and restore de oem cai.

SloopJohnB@mac.com

It's not the heat...it's the oil thrown on the MAF. Clean the MAF properly and get back to stock. While you're in there with the MAF off you can also clean the throttle body, just spray cleaner on it...do NOT try to move the throttle plate with your fingers.

Just Me

i am surprised by that statement. I don't doubt any improvement is marginal. I dont doubt that if mis-oiled, it can damage the MAF. But is it actually more restrictive? The one time i saw tests it was not the case. Close. Darn near misleading ads, but it did indeed flow better than most paper filters (in whatever car they did the test in - i dont recall, it was a VWAG product)

G