urban_cowboy

I had thought about the bungs being install wrong, but we followed the directions and Moroso was pretty adamant that they do not work well with mufflers. At idle, the evac bungs do create some vacuum, but fall down above 3k where I need them. My pressure issues are at WOT, not at idle.

If I run filter breathers, at WOT they drip oil onto the headers and smokes which is a little dangerous and embarrassing when pulling up to a light. The reason I run two breathers/evac connections on each valve cover is I push the dip stick out of the tube if I only run one when I get into it hard (above 5k). I also installed a bypass hose from the oil pan above the oil level to the valve cover to help with pressure equalization. With my large capacity pan no oil restrictions in my Dart block, and high volume oil pump, I was having oil draining issues at very high rpms which lead to a pressure equalization and draining issue. Oil comes out of everywhere it can about a few WOT pulls. It will come out of the dip stick tube, if there is no where for it to go. It comes out the breathers if I run them. It come out the rear main seal some (installed a new one before I realized what the issue was).

I should probably explain that this motor is a Dart stroker running at 500ft*lbs range and lives in the 3500-4500 rpm range and does so for a hour at a time. It basically never sees below 3000 and I current have a rev limit chip set at 7k which puts me shifting at about 6500-6700. Cylinder compression is great with less than 10% leak down, so blow by is not an issue. The compression ratio is about 10.2:1 on pump gas, so I am not running an exotic fuel. I am boasting, but simply trying to explain my situation. Motors like this create more than stock crankcase pressure, which is pretty normal in the racing world. Idling, there is no real issue, but at rpm, I need a way to keep the crankcase pressure down. Most guys I know simply run a Moroso vacuum pump and forget it, but they are running circle track or drag strips, not the street. I thought I could take care of it with a really good PCV, but that just trashed my intake and plugs. I thought an exhaust evac would work, but it does not relieve the pressure at WOT. I thought K&N breathers might work, which they do, but they drip oil on the headers. Currently I am running Moroso evac breathers with AN-12 hose just running down to the bottom of the car. This helps the engine breath without dripping oil onto hot headers, but is less than ideal.

I have read about the gz pumps, and am leaning that way. I simply do not know anyone who has run a vacuum pump on the street. That is the direction I am leaning, but would love to hear the ins and outs from some people who have put some miles on them.

I am looking for something that will 1. remove my crankcase pressure at high rpm 2. help minimize oil push and leak from crankcase pressure 3. maintain 10-12" vacuum for performance reasons (adds 25-30hp on most performance motors) 4. will survive 3k-5k miles on the street before needing a rebuild or refresh 5. is not a huge PIA to install under the hood since I am also running an alt, PS, and AC.

Thanks guys for the good feed back. Keep the good ideas and discussion coming.

FoxGT

Sounds like you answered your own question. You said the k&n filters work. Why not run them with a catch can to separate the oil? & at the bottom of the catch can have a line going to the fitting that you put in your oil pan to let the oil drain back down into the pan. Then have a check valve/breather on the top of the can & another check valve on the lower intake going into the lifter valley with a filter so fresh air can come in through the lifter valey, through the crank case, to the valve covers, catchcan, then into the intake under cruise conditions. Then at wot, the valve on the rear of the intake closes & the one on the catch can opens to vent to atmosphere.


(excuse the horrid drawing)

urban_cowboy

Interesting. Have you run this type of setup? Does it release enough pressure to limit oil push? I am thinking turbo and boosted applications have to run into this issue in a similar way.

FoxGT

The amount of pressure it can vent off is going to depend on your lines/filter/one way valve. If your lines are too small you'll run into issues. If the filter or one way valve is too small you could run bigger ones or install a 2nd one.

My setup was only with one valve cover line & the intake line going to before the throttle body so it wouldn't blow boost into the catch can, but since you're n/a you can run yours after the throttle plate. The reason I put it going to both valve covers in the picture is because you said you weren't having much luck with one