Thread: Modifying TD5 Airbox

I have been reading up on the TD5 issues some guys are having with tuning and realised that my TD5 could do with a bit more airflow. I got The idea of cutting the obstructions out of the airbox from the MAF bypass thread. I had a photo but had no idea what i was in for until i actually tried it. Hopefully this stops people making the mistake i made of putting a small nick in the bottom by over cutting the bottom half of the tube.

TD5 MAF Bypass

First I had to remove the airbox which was pretty simple once the connectors are off it just lifts out.



Airbox Before:



Inside the tube type thing there is a hiclone looking bit of plastic that takes up most of the realestate inside the tube. I forgot to take photos of mine but this is a puma airbox so you can see what i mean



The next step was to cut the tube off with a dremel so that the finished result looks like this. you Must leave the bottom 1/2 of this tube alone ( see why below)





you can see that the airflow will now be nowhere near as restricted. the hi-clone thing will have no effect on performance as any benefit or increase in flow gained from it will be immediately disrupted by the panel filter less than 2 inches away. I noticed no decrease in bottom end torque as suggested in other threads, driving has been improved by this mod and the car no longer has a flat spot just as the turbo is spooling up and also at high revs.

This was some of the remains of the inside of the air box once i was done so it is not an insignificant amount of plastic that is removed from inside there.





Now for the WARNING

I did not have a good look under the airbox before i started cutting and I missed a key design on the box itself that you must take into consideration when doing this.



you will notice that the 'tube' is actually recessed into the bottom of the airbox so that the bottom of the tube sits lower than the bottom of the airbox. if you are cutting be very careful that you stop before you get too low of you will go right through the bottom of the airbox as THE BOTTOM OF THE TUBE IS THE BOTTOM OF THE BOX

I was trying ot be too fancy and cut the tube off level with the internal floor of the air box and I put a small nick in the bottom of mine so I ended up welding some of the plastic off cuts into the gap inside and outside until waterproof again and then filling both grooves on the bottom 100% with silicone from underneath as extra insurance. I also filled in the square hole in the bottom with silicone as this lets in water and small debris.

I tested the 'duckbill' drain on mine by submerging the air box into a bucket of water and the duckbill valve did at it was designed and kept the water from entering, likewise when i filled the inside of the box it drained well which I am happy about. ( I do not plan on getting this submerged if i can help it or there will be lots of water in the cab before it gets in the air box. lol

For those that are interested I found it best the use a small grinding wheel on a dremel with the flexible head extenstion to make the top cuts then I used a small penut grinder on the flexi dremel to grind away the webs and clean it all up. I also used a soldering iorn to make some of the cuts as this was very precise and like a hot knife through butter

Not a bad way to spend a couple of hours and for me worth the end result as it can only help .

Cheers

Josh

Originally Posted by John W

Do you think the hiclone thing would have any role catching moisture from a snorkel and directing it to the duck bill ?

Only marginal...

But the rolled lip at the inner end does