boosted OBD1 s52 vacuum questions

[Dagamus(NM)]

Hi all, I have been slowly building up the s52 from my old M Coupe to go into my white MT2 vert.

I have most of everything assembled and have questions about the vacuum lines.

Fuel pressure regulator on the s50 rail, do I just connect it to the nipple on the intake manifold?

charcoal cannister line to??? I assume this should be on a line that only sees vacuum or atmospheric. I know there is a purge valve on the m20 and the s50 seems to have this as well but the s52 has something different. Confused about this.

Brake booster line needs a check valve I believe, any in particular I should look at using?

I assume I will have a few more questions as I progress but this is good for now.

[haaken675]

As far as i can tell, the FPR should go directly to the small vacuum port on the underside of the intake manifold towards the back. I would forgo the charcoal canister entirely.

I wasn't aware that there was any kind of check valve in line with the brake booster as I don't remember seeing one when I removed the old brake booster when I did my m52 swap. Also, what are you planning on doing for blow off valve vacuum, boost gauge vacuum, and MAP? I drilled and tapped my manifold for 1/8th npt fittings, and it seemed to work perfectly.

[Dagamus(NM)]

My manifold has several added ports for those. I know those all need to read the pressure from the manifold.

Just trying to figure out these ones.

Does the FPR not need negative pressure? Same with the booster?

[haaken675]

If by negative pressure, you mean vacuum, then yes the FPR definitely needs vacuum. If you instead meant positive pressure under boost, that's actually a good question. I'm not sure what happens to that under boost.

[haaken675]

From searching around (https://www.bimmerforums.com/forum/s...d-SAP-Solenoid) it looks like the only check valve needed would be for the brake booster and charcoal canister if you really feel inclined to run that...

[Dagamus(NM)]

Thank you sir. That is exactly what I needed to know.