Eugenio_SS,

Your definitely going to want to consider a vacuum pump. I've been exactly where you're heading and that setup will definitely benefit from one over trying a catch can. I was pressurizing the crank case on my ARE 382 with a 300 shot (at 200 it was fine). I talked to Mikey @ Rapid Motorsports about it and his recommendation was to definitely add a vacuum pump. Plus it's worth a few extra horsepower anyway.

 

crankcase pressure = bad. anything you can do to eliminate it is good. The factory setup is designed to take the pressure stock power creates, make more power, like everything else, it needs to be addressed. A vacum pump would surely benefit where you are going.

 

JL would u go breathers then or just run the pcv system w/a N/A setup.

 

For a N/A car I would just run the pcv setup with a catch can. If you are spraying excessively, say over 200, then the PCV is not gonna be enough, you will benefit from a vacum pump. For a FI car, it would make most sense to run a vacum system, just because a check valve in the PCV is gonna stop it from doing it's job of removing moisture and excess pressure once enough boost is being built to close the check valve, which is probably less than .5 lb of boost. THe check valve that would close once boost get's built would actually stop the pressure from being removed, causing a bad situation.

 

What would be involved in such a thing ?
Could it be located in the same place as the AIR-pump is now ?
Just trying to address all possible issues before they become problems.
Is it possible for the system to remain closed, with a vacuum pump ?
I don't feel like having a open system in the setup... will probably more nightmare for tuning.

 

I'm working on fabricating all that up right now and I'll have pictures shortly. I'm putting mine where the power steering pump was. You could also mount it where the AC pump was as well. It's belt driven, so no you cannot put it where the AIR pump was. You can try an electric evac pump, but it may not make nearly enough vacuum as a good vacuum pump can. For mine I'm going to drive it with a gimler drive off the front of the balancer as a second belt.

Yes, the system does remain closed with the pump. No breathers except on the breather tank. You do need a vacuum relief valve put in though. And an open system is not a nightmare for tuning. Mine came through pretty easy, yours should do the same.

 

How about an electric pump in my case for FI when im in the boost?? How much are these elec. pumps and were all can they be mounted?? How should they be hooked up? I am going to be having space up front were my battery sat.... will that be enough room? Im looking forward to your pic's Derty but with my blower mounted oin the front of the car i doubt i can go that route.
Kyle

 

Nasty- I would think that an electirc unit would be good for your FI setup, but as for the room it takes up and price, I don't know, I wasn't aware they even existed, let alone see one. I'm sure that it can't provide the vacum a mech. pump can, but I'm sure that it is probably better than nothing.

 

The electric one's are often referred to as scavenge pumps. You can get them to work, but they don't draw as much vacuum as a pulley driven unit. It would work moderately well on a street car I would think. I've never tried one or know anyone that has to tell you if it works well beyond that.

 

Si instead of wasting my money i should just run breathers on my valve covers and ditch the whole PCV setup??
Thanks
Kyle

 

Yeah, so far I had really good luck with my motor with just breathers and the LS6 PCV. But the PCV surely would have been optional.

 

For FI, I'd run breathers and ditch the PCV. The check valve that you have to run in line with the PCV to stop the boost from going into the crankcase is gonna stop the system from working anyway, ditch it. One less thing to worry about.

 

Derty,
Any progress on your vacuum pump setup? I am thinking of running something like that myself.
These days my car lives most of its life at WOT and the stock PCV system does nothing at WOT. I am getting some blowby out my fresh air inlet line (off of the valve cover) - that tells me I am getting no vacuum in the crankcase, which makes sense making pass after pass at the track.
I don't get any oil at the fresh air line with normal street driving (because there is actually some manifold vacuum).

I was thinking of doing a belt driven vacuum pump (Moroso or other) and use a Jaz tank with a breather to push the air to. I was also thinking of a breather on the PS valve cover (in place of the oil fill cap) and put the vacuum breaker set at about 22" in the DS valve cover. Should I adapt it to take suction from the LS6 valley pan connection that I have, or does it have to be from the valve cover?

Does this sound like a good idea??
I would rather have an electric pump, but have not found a good pump yet.

Thanks for any help!

 

You are going to get the best draw by taking the vacuum off the top of each valve cover. The vacuum pump will suck out of a sealed crank case perfectly. It has an outlet fitting that goes to a breather tank like a Moroso, Summit or Jaz tank. You can put the vacuum relief into a valve cover, that'll work fine. No breathers will be required on the motor.

I'm actually getting my bracket out to the machine shop today to locate the pump where the power steering pump used to be. There is no reason you cannot mock this up to fit where the AC goes as well. I'm going to run a gimler drive, so I'm basically waiting for Petersen Fluid to send me the 14 tooth gimler for the front of my ATI damper. I'll snap a couple pics of what I have for you tonight while I'm working on the car.

 

If I remember correctly Tony ran open breathers on his MTI 434 motor and destroy the rings (or something along those lines)....

I really do not see it being practical to use pumps and such for the PCV system until it's an all out race car spraying HUGE shots of nitrous (large increase in pressure)

 

Derty,
Thanks for the help! I wanna put it where the AC was cause I still have PS.

One thing I wondered about - if you don't use any breather and only the vacuum breaker, isn't it going to be open all of the time? I know its job is to maintain the set vacuum on the crankcase, but is it OK to suck air through the vacuum breaker all of the time? or is it supposed to be a safety backup if the breather can't let enough fresh air in? Just wondering.

Damian,
The reason a setup like this is needed is because when your engine is at WOT, there is no vacuum to pull through the PCV system - that is why it has a check valve. The thing is that the engineers that designed the stock system didn't design it for a car that would spend a majority of its life at WOT like a strip (mostly)/street car. It is good for ring seal and also increases HP to have a vacuum under the pistons (in the crankcase). This is the case in any car, not just one with N2O or boost.

 

You cannot suck out of the breather tank. The vacuum flows in one direction at all times, therefore it's always moving in the right direction.

Here is how I'm fabricating mine up. Unfortunately the space where the AC goes is taken up so I'm mounting it up higher. That would have been my first choice though. You can see how I'm fabricating my bracket so far. It's a paper copy of one that will be cut out of aluminum.

http://www.derty.org/photogallery/ca....php?cat_id=45

I'm going to use a Gimler on a spline drive attached to the front of the balancer as well. The HTD behind my pulley will be occupied as well. Here's how I'm going to drive mine: http://www.petersonfluidsys.com/Photos/dragdrive.jpg

 

Derty,
Thanks! I must have confused you - I didn't mean suck out of the breather tank. What I meant was whether the engine should have only the vacuum breaker or a breather - but after more research I understand that it should be sealed and only have the vacuum breaker.

Actually, I have come to the conclusion that I can't afford all of the stuff it will take to do the belt driven pump, so I have decided to go another direction that I think will work for my particular setup.

I am going to use a header crankcase evacuation setup when I am at the track with the exhaust open, and leave my stock PCV suction for the street. I will block the fresh air inlet line to the valve cover though.

When I am in street trim, I will either use an isolation valve (if I can find one that will withstand the heat) between the header and check valves, or use a pipe cap to cap it off so I don't blow the check valves out while the cutout is capped. When I am cruising around on the street like this (with some manifold vacuum) the factory PCV will suck from the sealed up engine through my current LS6 valley pan.

When I go to the track, I will open my cutout and either open the isolation valve on each header or take off the pipe cap and hook up the lines with the check valves. The factory PCV will act as a check valve to seal off the line from the LS6 valley cover to the manifold.

I plan to get another valve cover with the large oil fill hole for the DS, and pick up some of the old style PCV attachments (the plastic part that was on the DS back of 98's) and modify them to accept one crankcase evacuation system air/oil seperator on each stock valve cover.

I realize it will be a few minutes worth of work for me each time I go to the track, but I will be getting the advantages of an evacuation system while I am racing for a cost of about $150 max. You got to use ingenuity when you don't have much cash! I think it is going to work good for me.

 

I'd reccommend a catch can in with the factory PCV to stop oil from getting into the intake. I'm sure the engine's not gonna like that oil in the intake on the spray. The setup that you are talking about sounds like it should work well,let me make sure I have this right: you are gonna run a race style tube setup at the track, with a quick connect style setup for the hose that goes to the headers and valve covers, both that will be acpped for street use, and a check valve setup for the factory PCV for track use. I wonder if you could get a small ball valve or something that you could close off the factory PCV at the engine and the manafold for when you are at the track. May be easier with something like that. Just a thought, but overall sounds like you have a good way of having a race setup and a street setup that can be swapped in about 15 minutes, with minmal cost. Good engineering.

 

the way it should be done and the way I do it with my blower combo, is the fresh air vent for the pcv system is routed to the blowers inlet. Here's a pic of mine-
http://community.webshots.com/photo/...34594911XkfPKY
Once the check valve on the pcv side is closed under boost, the blower is pulling on the vent line relieving any pressure that gets built up in the crank case just like a sealed vacuum pump system does.
This pulls the crank case clean at WOT and I have never had an instance of the crankcase being pressurized at up to 15psi boost.

Steve