[JustJeff]

Originally Posted by Pete_89T2

Yup, these check valves don't really restrict airflow all that much in the "open" direction, and they completely block airflow in the "closed" direction. That's not what you want for plumbing the MAP pressure sensor or a boost gauge - what you want is a restriction in the airflow, which has the effect of dampening the transient pressure spikes your MAP sensor or boost gauge would see.

The restrictor pill is a little plastic thingy with a tiny hole thru it that fits inside the vacuum hose. Most of us loose these when replacing old worn out vacuum hoses. You can fabricate one pretty easily as follows:

1. Get a straight-thru style vacuum hose coupler.
2. Fill the inside of the coupler with some epoxy putty or JB weld.
3. Before epoxy fully hardens, run a pin through it to create your restrictive path for airflow.

I don't own any epoxy or JB Weld. I cut open the vacuum hose from the N/A sensor hoping I'd find one. But no luck.

Originally Posted by LunchboxCritter

Advance auto parts has those restrictor pills, they are like a buck.

Thanks you!! I need to go there tomorrow anyway and was gonna ask. Sounds like I can get the actual part for cheaper than rigging something up.