Guys Bear with me here. i have done some reserch and i have read alot good and bad enough to be on the fence. It seems my current engine needs an evac system. I currently dont have a pcv system which will be my first attempt . I dont have a real bad blow by just some puffs of smoke. The smoke does not bug me but just in one area of the intake gasket im pushing a little bit of oil (egr port ) . Not at an alarming rate but its happening . I am using a steel shim intake gasket. Which i normally lightly use rtv around the ports and surfaces on but this time i opted to coat with the copper spray. Could also be mating surface possibly due to the nature of the leak and its only in one isolated area. Im asking because i have an evac system but i do have a street car. Some guys have said they have ran them with mufflers , chambered not chambered with success and some have left clouds of smoke. Now i run an x pipe and due to the nature of the x pipe exhaust velocity is much faster . Could i run the evac set up on the collectors ? should i run them after X junction , or should i run them after the muffler ? I have never ran an evac system so this is all new to me.

Now another question is does the evac pull at idle ? will a pcv benifit me more. Both are easy enough to do imo so this comes down to what will work best based on collective information. I had a previous combination that was pushing the oil filler cap off and pushing oil out. My lack of knowledge at the time drove me to just make the cap fit tighter and i never looked back.

 

EVAC systems are for race cars, not street cars. If you have a street car, install a proper PCV system and be done with it, no need for the expense and complications of an EVAC syastem. IMHO.

 

From what i read is the evac system wont work untill higher rpms where the exhaust starts producing vacuum ?. Im going to install the pcv system aince i have it and its simple enough but im tempted to try the evac since i have it. The claim is you will see an increase in hp. I would like to try this for this reason too., my problem is where can i run it safely since i run an exhaust.

 

I've not heard of it done with the exhaust much. My dad has ran an electric one in his race car. and once used one of those engine driven pumps, that I think was used to pump fresh air into the exhaust or something, anyways he hooked the intake of the pump to the valve cover to act as a vacuum pump. A simple down draft tube may work

 

Im just talking about the evac set up that uses the old anti backfiring valves. I find it easier for weld ont o the exhaust so i think im going to play with it and see what it does.

 

There is a ton of trial and error when it comes to a pan evac. The check valves come in many different vacuum sizes and the location of the fitting in the header is extremely critical for it to work properly. Unless you have ultra low tension rings it's not worth your time because that's the way you gain power is by helping the ring seal.

 

To answer one question: They go in the collector.

Just to clarify the headers should be scavenging the exhaust at all times, no matter the rpm. With that in mind the evac system is always drawing the gases out of the crankcase barring any obstruction downstream of the headers. Your evac pipes are cut on a 45 degree angle and should be installed that way with the angle parallel to the collector. Same effect as if you were to blow across a glass soda bottle. It scavenges the gases out pulling them from the crankcase.

 

I understand how that works. I was asking because a few guys on yellow bullet have ran them at the mufflers and after the collectors and they still pulled vacuum. Im going to do mine at the collector. It seems plenty of guys have had success running them with flowmasters and they are the worst flowing mufflers so i should be fine.

 

I suggest the collector because that is the point where the gases are moving the fastest and pulling the most vacuum. As the column of air flows through the exhaust it cools reducing volume and vacuum. Dropping into the muffler would reduce the vacuum even more.
This is why you can get away with dropping tail pipe size by one ratio and still not lose power. The exhaust has cooled and become denser at that point and doesn't require the bigger pipe to keep velocity up.

 

First thing is trying the pcv out and if that dont help evac set up follows. The reason for mentioning the mounting location elsewhere besides the collector is because some guys say the mufflers add too much back pressure for them to properly work. I have never ran an evac system and there seems to be good and bad with running them with mufflers but it can vary from application to application. When the time comes if I need to I will install them in the collector. I was told a simple way to check if it works is put a vacuum gauge on the valve . Some guys say it should pull vacuum at idle . At this point it becomes a thing of I gotta do it to find out because there is a lot of mixed emotions about running the evac set up and where it works best , where it has worked for some and if it even works with mufflers etc etc.