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Air Filter

2578 Views 3 Replies 2 Participants Last post by  BuddyDog
Having finally got my car back after the engine replacement ordeal, I was keen to install my new K&N filter which I had bought of a UK site. Ironically it arrived within days of the car going into the shop! I hate getting new toys and not being able to play with them. When I got the car back I wanted to let some time pass before fitting the filter, for two reasons (1) i didnt want Audi to blame my mods for anything (2) I wanted to readjust to driving the TT after a sad month in a Toyota Echo.
It took less than an hour to haul out the original filter box and install the new one. I couldnt fit two components however; the breather hose filter (there is no breather hose on my car??) and the cool air hose from the bumper vent (despite the instructions, there is NO way I can get it up from the vent to the filter bay). I may need some feedback from K&N on this.
All done and checked, I started the car and pulled out for a test drive. I was hardly 200m down the road and noticed the strangest sound on acceleration and when I put in the clutch. Also, what looked like smoke was coming from under the bonnet. Major panic followed, I could believe that I was about to destroy a brand new engine! I limped down the road to a friend and we gave it some thought. The smoke turned out to be rain evaporating off the radiator from a light drizzle earlier in the morning. We reasoned that the strange sound was that removing the filter box had taken away the sound damping and this was now coming through loud and clear. Not much to be done about that.
So far so good. K&N claim up to a 10% increase in HP with this filter. I cant verify that but I can say there is a definite power increase and the engine runs alot more smoothly and feels less inhibited. I am curious to know if anyone else has experience with installing after-market filters and their feedback.
In the photo, the new filter attached directly to the MAS. On the lower right is the inlet port from the wheel arch that fed cool air directly into the original filter box. I am hoping that this is an adequate alternative to the cool air hose supplied with the filter kit. If possible I still want to figure out a way to get this installed.


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Hi Kelvin,

I don't know if you have seen an alternative, but there is a very popular CAI for the TT's made by a TT'er in the USA called the TTDA, which is the Twin Tube Dynamic Airbox.

It uses the K & N Filter, but encases it in an insulated Tube which has 2 air feeds.

The snorkel which fed air into the stock airbox should unbolt and you can wiggle it out. The nice thing on the TTDA is you stuff one intake hose into the area where the snorkel was and you can route the other under the battery towards the headlight. If you are really determined, you can route the hoses to the left underside intake where the intercooler sits, but you would have to switch to a front mount intercooler.

Hopefully I can post this pic... :D



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Originally posted by Kelvin@Feb 15 2005, 09:40 PM
Hey BuddyDog, thats a very tidy looking package and makes alot of sense to insulate the filter from the heat of the engine compartment. I had not seen that and being out here, we are not spoiled for choice. Pity I did not see this when I was looking to buy! I have still not managed to fit the cool air hose but it looks like I may be able to send it down between the battery and the compartment wall but at a tight squeeze. I think I will have to flatten the hose slightly to achieve it.
After recently replacing the MAS I am concerned that the filter taking air from the compartment is not a good idea. The workshop foreman said that the MAS is quite sensitive to heat and installing the K&N may have contributed to the failure of the first one. I am not convinced about this but dont want to go replacing yet another one, they are not cheap (as if anything on this car is). I am recently feeling similar engine roughness & slightly lower power response and wondering if I am already heading that way. Any thoughts on this?
That's the beauty of the TTDA, as it insulates the air into the MAF, so you don't run into heat soak if you plumb it to run cooler air.

try looking in the TT discussion groups at for postings by Steve Schwing. If your K & N is the same size as he puts into his TTDA, maybe you can just go with his housing and use your existing K & N.

Cheers! :D
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