850 Volvos A couple of (useful?) links on the turbo

[JimBee]

I've mainly worked on n/a 850's but am redoing vacuum lines on a turbo 850 now for the first time and trying to understand the engineering and dynamics of everything. This is based on my noobie turbo understanding, so no offense taken if others sharpen up the accuracy here.

Routing vacuum hoses:
This link is a good basic primer on where 3 of them go: https://www.matthewsvolvosite.com/forums ... =1&t=32575

The #20 hose runs from the bypass valve that has a diaphragm inside that opens and closes based on raw vacuum from rpm's. It connects to a direct vacuum source for its input—which I believe is on the front/left end of the intake manifold. Could it also plug into the tree? Not sure. I think Ben850 mentioned that the tree has other "parasitic" draws from it, so you might not get a a full vacuum draft if plugged on there versus directly into the manifold. The ipd external bypass valve video helps to explain how this part works:


Last year mercuric went into some detail about the process here:
https://www.matthewsvolvosite.com/forums ... =1&t=57839

As I said, other insights welcome!