I was looking under the hood of my friend's X the other day and something seems odd to me ... the hose that connects the DV to the IC piping. I'm sure there is a good reason, but why is it venting pressure from the post IC pipe when there is a perfectly good IC pipe 3" from the DV?

I know that pretty much all Evo setups vent pressure from just before the TB, and I can kind of understand it. However, not all DVs are set up this way. the VW 1.8t for instance vents from the IC pipe about 8" after the turbo and back in to the intake. This makes sense to me because it's a fairly short route. It's all one pressure system, right?

My question is this ... why not just rotate the DV 90º clockwise and source boost from the IC pipe that is mere inches from it? Is it a surge issue? Is it just better to vent boost post IC? I just think that removing that 3' pipe going to the DV could really help spool time ...

 

So, no one has an answer?

 

Its always better to vent boost as close to the TB as possible. Its healthier for the turbo and thus the car.

Eric

 

A big reason as well is that there is almost always a pressure drop after the intercooler, and if the bov is getting pressure from the hot pipe before the ic then there will theoretically be more boost trying to open the valve than there will be trying to keep it closed by the intake manifold line. What this means is boost leaks, which is no good. Hope this helps.

 

The Evo setup the air is cooler while VW's reroute warmer pre intercooled air.