I am new to superchargers.. 2001 GMC C3 with magnacharger radix with dynotech headers, built 4L60E with 2500 stall. otherwise stock LQ4.
Currently boost gage is plumbed to rear of charger housing at appears to be upper intake. gage shows vacum but not boost. I have not found diagram to show if should be boost at this location..
Also if I disconnect vacum hose to bypass valve the charger has some knocking/rattling noise... Is this normal??? with vacum connected it sounds fine.
Any info on this combination would be appreciated..

 

How much vacume at idle are you reading? Yeah there is a little brass fitting on the rear of the manifold, diver's side of center.

 

approx 16" vacum at idle... the hose barb that my gage is attached to is on the upper housing on passenger side of two other fittings.. it points directly to the firewall.

 

You need to attach it too the lower manifold in the back. There is a 1/8 inch nipple, remove the cover and attach your boost gauge there.

 

You could T off of the line going to the fuel pressure regulator but it looks crappy.

 

Thanks guys for your replies...
BlownChevy, the 1/8" nipple you are referring to is at rear on driver side, drilled verticle so nipple would point directly upward?
Is the noise in supercharger normal when bypass valve vacum is disconnected? but normal when vacum attached?

 

Do not disconnect the bypass valve.

 

Yes.


lol, you said nipple

 

hey guys. I googled nipple and found this thread, where they at?

 

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