Two Way Manifold Vacuum Hook-Up (1 Viewer)

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Hee Guys,

Just need some advice/thoughts from all you 2F/3F guru's in this forum section.
I'm thinking of hooking up a nice vacuum dash gauge.
Now I'm reading the numbers with a regular gauge from my manifold at #1 & #2. (red box in pic)

1)Would there be any added value in hooking up my new dash vacuum gauge with an Y tube to both red box & blue box?

2)What would the effect be if I disconnect/block my PCV to manifold and let the PCV valve run into a oil separator filter. (currently, I have a in-line oil/water filter from an air compressor in my PCV to manifold line)

Thanks guys!!
manifoldvacuum.jpg
 
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There is a vacuum port at the base of the carb insulator plate that is actually right in the middle of the manifold, right at the base of the carb. This port is supposed to be used to pull the fuel evap vapors back into the intake via the evap vcv. If a tee were place in this line, it should show balanced vacuum.....I think. I have my vac gauge hooked to the a/c idle up vacuum port that is adjacent to the brake booster port, taken off of #s 5 and 6 runner.......I think having a more balanced signal would be better for monitoring engine conditions.....HTH
 
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Anyway, got myself a very sweet deal on a new Holley 350 2bbl carb. I've put in extended jets, 10,5 powervalve, ventbaffle and a electric choke. I'm installing the Holley next month. The Aisin carb is going in the box as backup.
I will do some testing with a manifold Y tube hook-up on my vacuum gauge. If I get a steady reading on both red box & blue box (first pic in post) i'm installing the dash gauge on both. Should indeed be a more balanced signal.

Still leaves the question about disconnect/block my PCV to manifold line........................
 
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Lambcrusher,
Are you suggesting the point in green box (see pic?) Next to dizzy vacuum advance line? :confused:


Nope, other side, 180* around the carb. The insulator plate I see in your pic, the spacer below the carb and above the intake, may or may not have a port on the vehicles left side.... the later insulators have this port, I think I have a small spacer w/ the port also, some spacers may not have it. Anyway, if this port is available, I would figure that it would be the best rendition of what overall engine vacuum is because it is true manifold vacuum before the runner split.....Your model may vary.
 
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In the 60 series section of this forum, there are desmog threads which have detailed how to cut/block the egr port, but leave the pcv port-



Anyone think there is a good reason that the pcv line could not be used as the vacuum gauge source? Anyone? (could be killing 2 birds at once here.....)



I don't see why not to run the pcv as it is just a hose and won't affect performance:meh:
 
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Ahhh, now I know what you mean. Look at the pic. It's my new Holley on a conversion base I got from Ebay. This guy had a Holley on his 2F and sold the adaptor to me.
It's clearly got 2 (!?!) vacuum ports, which he closed with a small tube. This would be the point you're talking about...
Well, that's just perfect for when my Holley is going to feed the 3F beast. :D Thanks for your input !!:clap:

Thinking a bit futher about this PCV to manifold stuff

I'm living in an area with a constant temperature between 80° & 90° F. So I'm not having to deal with cold starts in the morning... We don't have any regulations regarding smog or what else. You can pretty much do to your car whatever you want...
I always thought that the cooler your gas mixture going into manifold, the better. With the PCV connected to my manifold, it's getting hot air from inside the valve cover back into my manifold, combined with the (cooler) air( air/fuel mix) from my air filter.
If I cut the PCV to manifold,...won't my air/fuel mixture going in be cooler, compared to the current situation????? Thus more performance???

Any Guru wish to comment????
vacuumpoint.jpg
 

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