Electric vacuum pump vs. EVAC

[Minella]

Hi Guys!

I'm building a 390 only for race and i would discuss about a crankcase evacuation system.
I know that mechanical vacuum pump, like Moroso will give the best results, but to me is too expensive than i'm thinking in two other options:
1 - Moroso Crankcase evacuation system conected to the headers($55,00);
2 - GM electric smog pump running counterclock($80,00)

First of all, Anyone using those systems?
which system pulls more vacuum?

Thanks a lot

 

[inkjunkie]

had a friend who swore by the moroso set up. it was simple and cheap. he was running around 14-1 comp. and a very light ring set up...

 

[earthmover]

from my understanding if you run muff. with the moroso kit it doesnt work,but if you only run headers its a great kit...i had plans to put the kit back on my car with the muff. and thats what i was told ...they had a few post about this over on moparts a few weeks ago...:read2:

 

[inkjunkie]

i have read that in several spots also....

 

[Guitar Jones]

I have used the pan evac system with a 3" exhaust and Flow Masters before and it worked. But, I didn't use the kit valves as the suction needed for them to open was too high. I used aspirator valves from a /6 Volare air pump setup. I don't remember what year or what the part numbers were though. I'm not even sure if they are still available. Additionally I cut pie shaped cuts in the tubes welded into the collectors facing the exhaust flow. This increased the suction to open the valves.

I have seen the vacuum pump assembly make as much as 30 horsepower over an evac system on the dyno with a 351 Ford Super Stock engine though. So depending on what your application is you may want to consider that money well spent.

 

[moper]

There's a big difference between an electric vacuum pump (like for accessories such as brakes, etc) and a competiton vacuum pump, and the EVAC systems. The vacuum pumps cannot move enough air to pull vacuum in the crank case. And that is what helps the rings seal to make more power. The EVAC system will not pull enough air to do that either. It does work well, but there is only so much work exh gas flow can do for you. The valves can be gotten in diferent vacuum ratings. I think looking up Ford Air Pump Check Valves were where I've found the varous ones. In any event, a real competition crankcase vacuum pump will pull a decent consistant vacuum. That's what you need if you are looking to take advantage of it. I think for a typical small block the Moroso 3 vane would pull enough air to get 12-15". Not sure what this one can do but it's electric: http://www.fastbygast.com/Catagories/Products/description/vacuum.asp
You could also just spring for a dry sump system to make more power and pull vacuum at the same time. Again, won't pull serious vacuum (most guys from what I can tell want 15-20") but it should get past 10".