Vacuum Line Routing

[CV355]

I'm working on making all vacuum lines braided steel line just for aesthetics.  While picking out what fittings I need, I noticed something and figured it would make sense to ask.  On my Sniper EFI, there are three vacuum ports in the back - two 3/16 and one 3/8 for vac manifold, booster, and distributor respectively.  I am not running a vacuum advance distributor, and my Performer RPM intake already has a vacuum port, so I am assuming there is no need to use any of the 3 ports on the throttle body.

Here's the schematic I'm working on so I can get part numbers on order (UPDATED IN POST 5).  Is the carb line even necessary in this case?  It seems like the "source" vacuum could be the carb or the intake manifold, so which is preferred?

[GerryP]

From your diagram, the carb run isn't necessary.  And it doesn't matter from where you take the vacuum since either source is still coming from a manifold and the signal will be identical.  The only thing you have to pay attention to is if the line has sufficient flow.  A 3/8" line is plenty.  You might get some suggestions about running the brake vacuum booster from a common line shared by the PCV.  The advice is to run it from something separate from the PCV.  Okay.  But if you put a vacuum gauge on a line running PCV and the brake booster, you will see the signal is the same as it is from an isolated source.  Again, it's a manifold, so signal is uniform throughout.

[Gaugster]

From the diagram I assume you have a push through turbo/supercharger with a blow off valve? You might need something more than rubber caps on the Sniper EFI ports. But is depends on how much boost you run. One of those vacuum ports is topside of the butterflies and will see a surge if the throttle closes rapidly prior to BOV doing its thing.

[427John]

From your diagram, the carb run isn't necessary.  And it doesn't matter from where you take the vacuum since either source is still coming from a manifold and the signal will be identical.  The only thing you have to pay attention to is if the line has sufficient flow.  A 3/8" line is plenty.  You might get some suggestions about running the brake vacuum booster from a common line shared by the PCV.  The advice is to run it from something separate from the PCV.  Okay.  But if you put a vacuum gauge on a line running PCV and the brake booster, you will see the signal is the same as it is from an isolated source.  Again, it's a manifold, so signal is uniform throughout.

I think the brake booster on a separate port thing is about  being worried that if the airflow exceeds the capacity of the tube size you might have insufficient vacuum to operate the brakes,while I don't know how valid that concern is,I wouldn't argue the point.

[CV355]

Here's my new routing diagram.  Good point on the booster/PCV being separated.  I changed it to pull from the throttle body so the PCV distribution is even (I'm probably overthinking it, but the alternative is the #5 runner on the Performer RPM intake...)

From the diagram I assume you have a push through turbo/supercharger with a blow off valve? You might need something more than rubber caps on the Sniper EFI ports. But is depends on how much boost you run. One of those vacuum ports is topside of the butterflies and will see a surge if the throttle closes rapidly prior to BOV doing its thing.

It will be N/A for break-in and a short period of time while I design up an F1A Procharger mounting solution for it.  Hopefully it'll be running at 5-6psi by next summer.