I feel as though I have my daily driver running pretty solid. I do have a couple questions if someone can answer.

1. On my big block NA I had the evac tie into the down pipe, but on my turbo I have it running to a catch can only because that seems to be the consensus. My new engine has a 180,000 miles and there is some blow by out of the breather. Not a huge deal but curious as to why when running turbo's the consensus seems to be to use a catch can and not run it to the down pipe?

2. I have a UMI 90mm throttle body, attached to a vic jr elbow and intake. On the top of the throttle body was a tube that connected to a valve cover. I pulled that tube and never did anything with it. The car has always run well but tonight I was told I should plug that tube. It blows a little air out and was told that was a little boost I was losing. Again, the car had ran pretty well like that, running a 118mph in the 1/8th in a nearly 4,000 lb car. What are you guys doing with that tube or what do I need to do with mine. Just leave it open or plug it. Again, NO vacuum, it just blow some air when you give it gas. What symptoms would you see from NOT plugging it?

Thanks. Again, just trying to fine tune this thing and learn why I am doing something also.

 

Question #1 seems a bit confusing. Are you saying that when it was N/A you ran the EVAC to the exhaust which pulled the vacuum on the crankcase? And now it is turbo and your wondering why you have it going to the catchcan? If that is the case, going to the catchcan is just a vent, and the reason for not going to the downpipe I beleive is that there isnt enough vacuum in the downpipe to pull on the crankcase...so it would be pointless.

#2 Yes plug the port on the throttle body. Symptoms could be engine running rich because the mass flow sensor is calculating for X amount of air but some of it is leaking out the throttle body.

 

Here is the way to have a proper working pcv system. Going just to a breather setup is in now way a pcv system. Why would you want a pcv system ? Pulling fresh air through your engine increase the life of your oil / engine. A PCV system cleans the toxins, moisture and whatever other crap is in it.

Here is the proper way to have a functioning pcv system.

 

Thanks for the response. Okay, so how would you set it up using two catch cans and twin turbo's? Thanks again.

 

This is how I have mine, and it is sucking in a lot of oil into my intake piping and intercooler. Should I use another catch can on the line going to the turbo inlet? Sorry to hijack but, maybe someone else has the same problem.

 

No problem. I have the turbo fitting with a vacuum line to the bottom fitting on the wastegate, so I am not sure how to tie the catch cans into the turbo's.

 

You don't have to run the vent line to both both turbos pick the one on the passenger side and run it to the inlet of the turbo or pick up a small breather and install it instead of running a line to the vent.

 

Seems there are a number of ways to skin this cat. I am not sure I like oil mist going back into the intake personally. I have tried a number of catch cans and even the best seem to have oil mist get by to some degree. I am not sure what the answer is other than venting to atmosphere or a vacuum pump of some sort.

 

I saw a guy run his pcv to the exhaust in this thread

https://ls1tech.com/forums/forced-in...st-set-up.html