Was getting questions on this. It may have a revision or two left in it but is working excellently.

For the longest time I had a valvecover breather, one hose to btwn the air filter and turbo and thats it; But since the 88m install ive been having turbo drain "issues". I went from wanting an electric scavenge pump to a mechanical scavenge pump, to using the vaccum the engine allready has. Derr! it works damn good and I get some nice crankcase vaccum at any cruise to boot (which i hear is good for rings and stuff).

I'll continue to hokie around with trying to get a little more vaccum in the crankcase as well as work on a way to move more air out of the engine when the intake is under boost; better safe than sorry. Working on a large one way (out only) valve I can mount to the oil fil spot and then I'll be set.

Read the captions under the pictures:

http://www.fastrides.com/photos/mm/c...ture12042.aspx
http://www.fastrides.com/photos/mm/c...ture12034.aspx
http://www.fastrides.com/photos/mm/c...ture12035.aspx
http://www.fastrides.com/photos/mm/c...ture12036.aspx
http://www.fastrides.com/photos/mm/c...ture12037.aspx
http://www.fastrides.com/photos/mm/c...ture12038.aspx
http://www.fastrides.com/photos/mm/c...ture12040.aspx
http://www.fastrides.com/photos/mm/c...ture12041.aspx

Hooking the boost gauge up in this configuration I get 2" of vaccum at idle, up to say 5" at part throttle, and most importantly 0.0psi crankcase pressure at wide open full boost.

I HIGHLY reccomend anyone with turbo drain issues to try this method before throwing cash and complexity at an external scavenge system. Just make sure you dont boost the crankcase! Secondly dont just suck oil into the intake and foul plugs; ask me how I know.

 

so are you drawing out of your vally cover? with a check valve in line before the can, and between the tb? i was thinking of running both covers to a can along with the vally plug. then taking the line from the TB installing a check valve between it and the can. then hooking up my line to suck through the can. what do ya think?...if you can under stand what im rambling about?

btw.. thanks for the pics

 

first, i dont make use of the fitting on the tb, dont even have it anymore, i pulled it off and filled the hole with epoxy putty. hooking anything to that is not what you want to do if you are FI.

you can pull air from anywhere, but wherever your vaccum is hooked to, that is where you want the separator. my vaccum source is t'd off of the brake booster hose.
i could have done it at the valley cover but i didnt have a hidden spot for the separator up there, and i would have lost one of the vent hoses to the filter to turbo pipe.

the air gets pulled out of the drivers rear valvecover the way i have it, through the check valve, through the separator and into the intake.

your idea is great for pulling a vaccum, but you have no place for the crankcase to vent under load.

 

it would just vent back into the can.. right? i have a hose from the crank case to the can and both covers go to the can. then a vaccum source to the turbo. what would i need to do? where is your crank case venting to?

 

valve covers and crank case are the same place

if there is positive pressure in my engine it goes out the little black brake booster valve on my valvecover, or either of the two hoses from the crankcase (valvecover and valley cover) to between the filter and the turbo

 

Awesome! Thanks for the write up and pics, big help to us lowly newbs

 

Is this type of crankcase evacuation necessary on a supercharged application??
Also, you can run your pvc valve comming out of the valve cover into the brake booster?

 

If it helps at all. We hooked up PurEvl's setup to the inlet of the Turbo.Each valve cover has a 3/8 hose going to a T /fitting on the inlet.No check valves,just straight to it.So far (2k miles) there is no oil at all in the inlet and we've got no oil problems with 800rwhp -DD .

 

so basically i could run both valve covers straight to the intake b4 the turbo...with a catch can between to stop oil?

i was thinking of pluging the intake and tb holes and just running the valve covers to a catch can with a breather on it, would that work, or do i need the vac at high boost?

i like that first setup but it seems complicated, and i really would like to avoid running a pipe all the way back to my turbo (STS).....

if i am only running 8psi can i run just a breather style catch can?

 

blown bird-the brake booster hose is a vaccum source, yes you can run a line from the pcv valve to it, but i reccomend an oil catcher and if you are FI add a 1 way valve in there. remember you need to have some controlled 'leak' like i do with the two hoses to the turbo/filter pipe, or you will pull a LOT of vaccum

this setup isn't 'necessary' for supergarged set ups. but if you want to have a vaccum in the crankcase without having to have an electric or mechanical external pump, this is the way to do it.

slowhawk
pic 12035 is of my two 3/8" hoses going from my crankcase to the pipe between filter and turbo. you can certainly have just these but i strongly reccomend you use a boost gauge to see how much presssure you have inside the engine during WOT. You may find yourself with some psi in there you dont' want. If you are not interested in having a vaccum in the crankcase at all then you can just add a breather to the oil fill etc. or even putting some of these small cheap one way (exit only) valves on the other outlets of the valvecovers.

if you just have hoses from the crankcase out to the turbo/filter pipe, you may relieve some crank pressure at high airflow, but never draw a vaccum on the crankcase part throttles

navy mitch, i dont have mine set up that way at all, check the pictures again.
you COULD do that, but there really isnt any measurable oil to catch from those hoses. the oil comes from when you are sucking out of the engine with vaccum.

you certainly can run valvecovers to a breather, or just mount breathers to the valvecovers.. this however is not what i am talking about.

it is more complicated sure.. but i am having cake and eating it. and i dont have a jumbo catch can up at the front either.

let me repeat its not something anyone has to do, or something hp related.
I'm running vaccum in the crankcase to help scavenge the turbo #1. if you don't have this problem and arent interested in the other beneifits associated with crankcase vaccum then don't worry about it.

 

First off my break booster isnt hooked up to a vaccum source because there is no fitting on my carb or intake to hook it up to, therefore no power brakes. In my case, will hooking the pvc from the valve cover do anything if connected to the break booster or not?? Dont people run the pvc from their valve cover rite into a flange in their exaust collector for scavenging?? Im just not understanding why you need vaccum in the crankcasek, I always ran a breather on my valve cover, but thats when i was n/a

 

you should drill and tap a fitting into the intake so you can hook up your power brakes. it would be very important to me.

however, you can get intake vaccum from other ports not just the brake booster port. that one was convenient for me.

if you need to know the beneifits of having crankcase pressure then i suggest you research it. i am not an official on the subject, i just know that it is a good thing.

some race cars use the exhaust to scavenge, but that is not good for the oil getting flung onto the car underside and back end, nor for emissions.. race car only deal i think.

 

so..how much in parts do you think your setup cost?

i think i am gonna go with something more simple like just adding breathers and calling it a day...i know i wont get any vac in the crankcase but at least i wont have and pressure.

 

ok MM. with my idea what is wrong with it and what should i do. dont care about having a big can. run both valve covers to the can and have a line in fron t of the turbo. so with the vally plug sticking up... what should i do with it? also i think we got confused. i also have the tb port capped off. im talking about where the stock "checkvalve" is. i reckon its on the intake to the vally. so can i also take it to the can? so to recap both covers to the can, the vally plug to the can, a check valve between the inake and can. then my hose in front of the turbo. or am i missing something?

 

Dave

I was working on something similar to this but I was going to use electric scavage pumps, but it looks like you have a very economical solution.

I have 2 catch cans that are identical, if I run 1 to each valve cover and then the other end into my air filter will that work?

 

navymitch
the separator was 20
the 1 way booster valve was 3
the ball check valve was 15
hose was 20 (use fuel injection hose to deal with vaccum without collapsing)
3 way fitting was 3
hose clamps were 3
2 fittings to intake pipe were call it 3 total

$67 or something

just a valvecover breather (simplest) will run you $50 and at minimum i reccomend you replace the stock pcv valve with a ball check valve (they are all over the place on turbo type stores)

kaos
ok sounds good but the problem is that your can has a big breather on it correct? so you will never be able to sustain a vaccum inisde it.
what you can do is go from the valley plug to a separator to the intake port (where the stock pcv used to go, replacing the stock pcv valve or adding a ball check valve)

you can then go from both valvecovers to a catch can and from there out to in front of the turbo. but i would say you'd need at least the same size lines that came from the valvecovers out to in front of the turbo, you dont want to build pressure at all. for this reason i added that third one way valve on top of the engine at the extra port on the valvecover

just remember that your configuration and how much of a 'leak' you have will change the amount of vaccum you can get you dont want too much and none is worthless.

also keep in mind that your idle may need to be adjusted as all this air is comming in behind the throttlebody now.

boostaholic
you really need the catch can most on the vaccum side. the side from engine to air filter will only rarely be under the slightest vaccum (if your engine is built tight)

the spot on the engine where you hook intake vaccum to it is paramount you have a catch can and a nice 1 way valve

and please make sure you check your crankcase boost and vaccum before calling it a day. you may have to reconfigure a little to get the numbers you want.. i did.

some companies like moroso have a vaccum control valve where it lets air into the engine if there is too much vaccum inside. i dont like these cuz they are not filtered, and cost more than me just fooling with it a little bit more.

 

so when the engine goes under boost, the check valve to the brake booster closes right, then your venting the valve covers to the airfilter by the turbo right, does that have a check valve so air can only leave the system too?

 

Well what happens when I get into boost then? My check valves close and I have no crank case pressure venting?

 

smokinhawk, no the hoses to the valvecover are just hoses.. these are left without valves so i dont build too much vaccum.

boostaholic, i dont know what happens to your crankcase when you go into boost.. you should measure it.

either way any one way valves adjacent to the engine should be oriented so that air can only exit, not enter.

 

You missed my point, I already know what happens to MY car. I was asking about your car.

You say your using the engines natural vac to relieve crank case pressure and your using a check valve to stop air from coming back from the intake into your crank case - thats great for off boost driving, now lets talk about how you get the pressure out under boost, because vac off the intake is no good and you already stated that just running a line up to your air filter is no good.