Evolution Racewerks Turbo Inlet Pipe Type III Hard Black Anodized Finish Volkswagen Passat 1.8T Turbo with 3" MAF 98-05 | VW-INT001B-MAF3

As the turbo begins to spin and build boost pressure, the vacuum pressure created before the turbo starts to increase as well. With more boost, this vacuum pressure increases exponentially. The factory turbo inlet hose sits right before the turbo and is made of flexible rubber. With vacuum, it starts to "collapse" into itself (imagine a full ballon getting the air sucked out). Thus, the inner diameter of the factory inlet hose starts to shrink and get smaller. The more boost pressure, the more vacuum is created in front of the turbo. This creates a big problem as at peak boost, the facto