42 Draft Designs Inline Restrictor was designed specifically for VW engines. This custom fitting has a built-in vacuum restrictor in the center. A vacuum restrictor is essential to provide a clean signal to the boost gauge. If a mechanical boost gauge is installed on a turbo car without a vacuum restrictor the gauge will produce a buzzing noise. This fitting was designed to be used on VW engines that don't use a T-fitting. It can also be used any boost gauge installation using .170" - .1875" tubing.
This fitting is included in our TDI & MK5 boost gauge tubing kits