i never saw any real drop in pressure with my ebay inner cooler, but i am running a race valve and have been since my first n75 died

 

Have to understand that the air is going to take the path with the least resistance. So basically at first the air is going to go from the inlet pipe straight across to the outlet pipe, then when the pressure and resistance in that part of the car starts to increase the air then again finds paths with less resistance till the core is full.

If you increase the volume of the core between point A and point B then yes there will be more lag. Lag is also increased by going with IC pipes that are too big since that decreases the air velocity.

Also have to take into account that when the air cools it gets more dense, this effects the pressure on the cold side of the core. So does how well the car flows and the velocity of the air in the hot side pipe.

 

Good points! Thanks.

 

Would a 2.5" pipe for a k04 be too large?

 

I think thats good depending on your psi. Correct me if im wrong guys.

 

I wouldn't use 2.5" piping for a ko4. Definitely too big.

 

Yes seeing that I run 2.5" pipe on my A4 that is making 800chp.

For a K04 you dont need anything over 2". This is why the kits that are actually made for the K03/K04 on an A4 use a 2" pipe.