K&N drop in filter for 2.0T results/comments

Recently purchased a K&N drop in filter for my 2008 Gti and did some logs. At first it felt like it had more power and then I did some logs

What I found was that over most of the rev range the K&N produced less flow than the std air filter. Where i use to get between 197gs to 200gs peaks I was now only seeing 189gs to 192gs peaks and timing pull overall looked worse than before. For the life of me I could not figure out why this would be and did a couple of more runs in hot and cold weather and with two different fuels...almost no change.

Finally decided to put the standard filter back and had a look at the intake design and the two filters when I spotted the potential problem. When air flows into the intake the first point of contact with the filter is from the side. The standard paper filter's fins are open from the side and air flows directly onto/into the filter. With the K&N the story is different....it has a solid surrounding so air can only be taken in from the bottom of the filter and not from the side like the OEM filter. If you look at the flow pattern into the intake "box" the K&N actually acts as a restriction in air flow!!

My opinion is to rather stick with the OEM filter or get the full intake. I was advised to do this but wanted to do my own testing to prove it as I could not figure out why a K&N replacement filter will not flow more air than a OEM one. I searched high and low for some VAG data but could not find any so I had to do my own research

Hopefully I will help someone save some money :wink:

which engine do you have?

Quantumphysics said:

which engine do you have?

Click to expand...

read the thread title....ultimate failness

Quantumphysics said:

which engine do you have?

Click to expand...

If you mean AXX/BWA, he has a BWA. And if you want to know if he's got FSI/TSI, he's got FSI.

Thanx for the info Observer!

+1 :thumbsup:

Did some more logs with the old OEM filter back in and car is back to almost 200gs! That is almost 10gs more than with the K&N peak!
Timing pull is also back to normal levels on our poor fuel and another interesting fact I discovered is that the waste gate duty cycle also looks MUCH better!!! Looks like the turbo was really struggling to pull air through the K&N:eyebulge:

I'm shocked to see the poor results! Did the two logs in the graphs using the same tank of fuel and same temperature

That is shocking info. I have the K&N drop in, and I do feel a little bit better throttle response. I'll eventually get a full intake, but damn this is bugging me now. Thanks for your research though!

No problem...Do you still have your old filter and maybe a VAG cable? Would like to see someone do similar tests

I initially also thought that the filter have added some more grunt but the test definitely tells a different story (more timing pull, less flow, higher waste gate duty cycle). If you examine the OE filter vs the KN design and take into account the intake box it makes sense....or at least does to me

ahh damnit, now you just made me want to spend more money on an intake and get rid of my K&N! Nice logs though, thanks for the research!!

Moved.

does anyone have similar research with a newspeed or eurosport intake?

The shop where I bought the drop in filter is willing to supply me a S3 OEM filter (apparently it is different) as well as a Carbonio and K&N CAI to test. Wil probably do it mid Feb if I have some time available

No way you can feel a difference of 1 or 2 whp. Saved me money. Thanks.

Apparently the CAI kit does make a difference...just need to see how much
Don't think the Carbonio will make any extra horses but I will do some more tests in Feb

Very interesting - I wonder if the ITG filters have similar results.