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I guess your gonna ALWAYS BE RIGHT... no matter what
anyone says... keep calling it POUNDS of vac.. if
your happy then thats all that counts.... by the
way.. my gauges read both... but in the USA we tend
to use inch of HG... maybe you call it pounds of KPA..
I tried to help you out with just a little info and
thats all.... do what you want

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This whole subject matter requires much intense explanation and understanding…..comprehension is critical.
1. A vacuum pump is not intended to seal the piston rings. Fit, finish and cylinder pressure do that job.

2. A vacuum pump is used to control blow-by (pressure) that gets past the rings on the exhaust stroke. (minimal cylinder pressure)

3. Additionally, a vacuum pump is also used to reduce/eliminate ring flutter on all other strokes and allowing them to stabilize for the compression (power) stroke. The cylinder pressure will take over from there. (talking low tension packages)

4. Gain from increased negative pressure (vacuum) is really the result of the increased negative pressure “volume” offsetting the positive pressure that is being developed from what gets past the rings. (more is not better - just a bigger handicap)

5. A vacuum pump and a dry sump pump confuse the oil drain back process – modern technology has found its best NOT use a vacuum pump with a dry sump. If “blow-by” is under control, the dry sump pump can do both jobs – the core of this debate!

A few things I have learned and attempt to share, those comments above are only skimming the science part of the matter. I suggest if you really want to know, pursue learning….I’m way too lazy to type everything involved for a clear understanding.

If you still feel compelled to be sarcastic – get a life.

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I already quit with this.. I guess I better get a life...
as usual your right... maybe the others are wrong also

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Well, just for fun the next time you're driving. Cup your hand into about the same shape and size of one of your piston bottom. Now stick your hand in the wind multiply that by 8, and your fighting normal atmospheric pressure. Would be higher than ambient inside your engine without vacuum. Should you be driving on the moon, you'd feel nothing against your hand. Much like really high negative crank case pressure. Also oil droplets don't spray apart under high vac like they do in normal pressure. So less oil fog to help oil the pins as well. Galling wrist pins was common when people started driving the pressure down. Now most people run coated pins, or .002-.003 pin clearance when they plan for real vacuum. Clear evidence of less oil fog.

Drain back, and oil quality are better with a dry system. For whatever reason, I never have oiling related bearing problems wet. Mopar skirted blocks only provide a narrow opening to scrape the crank. Ford and Chevy are a whole different world giving you access to half the crank.

A good dry system is 4-5G, the best wet is 2G For me I'll run it wet with a pump. The 4.5 seconds I'm on the gas isn't going to make a huge difference in drain back anyway, and my bearings NEVER show any sign of wear from frothed oil.

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I only spent about $500 on the first big-block dry sump setup that I built. I used a wet sump pan with a swinging pickup and just hooked that up to the dry sump. I rounded up a used pump from a circle track team that was upgrading and found a cheap tank from someeone else who was upgrading. I built my own lines and used the cheaper brass and steel fittings rather than the expense aluminum ones. That dry sump setup worked just fine. The pump wasn't big enough to pull much pan vacuum, but the system had good oil pressure and I had all of the benefits of a dry sump. I covered the topic a little bit in this article:
http://www.hotrod.com/how-to/engine/mopp-1206-project-505-the-final-chapter/

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