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Fri Nov 20, 2009 5:23 pm

busman78 wrote: It is not intended to lower vacuum, it evacuates the case at a fixed rate, only "X" amount of crankcase fumes can pass through the orifice at any given RPM.

Ok, here you are losing me...so you want to pull 20+psi of vac thru your case, yet lower the volume?

busman78 wrote: I tested vacuum off the dipstick once, at around 3K rpm I had just a little over 3hg.

Can you explain hg? I tried the google. All I get is Mercury...

Fri Nov 20, 2009 5:54 pm

Okay, I should of used "inHg", Hg being the chemical sign for Mercury, so inHg is inches of mercury or in this case vacuum. Impossible to pull 30hg, intake would colapse into itself.

All this system does is control the amount of air that can enter the manifold, does the same as a PCV valve does, which is a restrictive valve so only so much crankcase fumes can be sucked at a given time under "X" amount of vacuum. The breather tower I am using originally came with a disk inside that acted like a PCV valve, only problem was it was closed at idle and I wanted scavenging at idle.

Consider the VW case as a large vessel or flask with two 1/2 inch holes, you can only draw so much vacuum against that vessel, I am getting a controlled air leak is another way of looking at it. Kind of like pulling a vacuum line off an intake manifold of a running engine, your vehicle would go super lean if you have a carb(s) set up, by controlling the leak, adjusting the fuel to compensate the engine does not know the difference and I get a good crank case breather set up.

Wed Nov 25, 2009 6:30 am

busdaddy wrote: On a 78 it's in the line above the LH accordian tube.

From Wildthings.

Okay, I do have that. Its laying loose in the engine bay. I am going to hook it back up today and see what happens. I wont have to rebleed or anything because I opened that system up, right?

Wed Nov 25, 2009 7:13 am

Nope, the vacuum is separate from the brake fluid unless you have major booster issues. The only result should be better brakes or in the worst case a very lean idle if the booster is leaking and that's why it's disconnected.
You may want to make sure there's no dirt or critters in the end of the line before you connect it to your engine if the end has been open, anything in there now will end up in your manifold.