Well that is the fun part.. since it is different on literally every single car, you don't know till you do it.

And even if you push no appreciable amount of oil, you are atleast giving it a safe place to go... as in not into the engine or under a wheel after popping the dipstick.

Oil in the intake fouls everything up and induces knock, sometimes severe knock.

Oil being forced out of the other escape path (dipstick) due to a restrictive PCV set up can result in a crash if it gets on or under the front tires.

The other benefit.. providing more significant vacuum to the PCV, might have been negated by your less restrictive intake system.

In which case I would then cap the nipple on the intake pipe and just route the hose to a cheap vacuum pump like you would find on a GM, or just buy a lower-end unit from Moroso or Summit.

Big block V8 guys actually pickup power from this, how much we would gain is tough to say. Boosted or N/A, but probably more on an N/A because few vac pumps can keep up with the often excess blowby from the higher BMEP created by the turbo. The added vacuum on an N/A can force the rings to the bores harder and reduce the force required to push the piston back down into the crank case.

It's a bit of a black art. But in any case a catch can will only help when set up properly.

Sorry for the long winded answer, but this is a subject that is often subject to much debate. Some parts are open to debate, most of what I typed above is not. I tried to avoid any controversial bits and my opinions/feelings on them to avoid conflict.

 

Other little oil related mods that can make a big difference would be crank scrapers and windage trays. They usually only require pulling the oil pan. Some might require popping the mains, but that really isn't so bad if you retorque them in sequence as long as the mains haven't yielded or reached service limit.







Then adding a tray or a screen to help baffle or control the oil using its own surface tension helps compound the effect. Obviously you want to leave room for the pickup on an L15, but this engine is actually using a dry sump and external pump and accumulator.

 

@DSM: you're clearly on the right path... you're making alot of sense

what is just bothering and nagging me is... if I run a single catch can that would accept a T barb directly from the PCV and the breather... where would I route the return line?

 

here's how it is on our engine...



PCV hose runs directly back up the intake manifold

 

For a single catch can in your situation:

• One line inbound from a tee fitting attached to the PCV and VC
• One line outbound to the Intake pipe

That is the traditional method.

This way the relative restriction of the intake pipe creates a pressure differential and pulls the blow-by gasses through the VC and the PCV, through the can and into the intake pipe.

Now my concern for your particular setup is that with the less restrictive intake you have picked up you may not have enough vacuum to perform this task.

In which case, you could skip the outbound hose to the intake and just plumb it to a vacuum pump. There would be a few advantages to this.

The most obvious being the added vacuum the pump could draw vs. the 2-8" Hg (~1-4psi) or less that you see in the intake system due to restriction and high velocity charge flow.

The second and the main one in my mind would be keeping all the combustion constituents and oil out of the engine.

This keeps the engine cleaner and increases resistance to knock, in some cases by a wide margin.

Engine oil effectively reduces the given octane of fuel you are using. Same thing with reversion from the exhaust, or "natural" EGR.

Because just like your EGR it is dumping burnt material into the combustion chamber. This fouls things and robs power.

Before someone jumps in to tell me how the EGR is for emissions... I know, and if you think that a small fraction of the exhaust gasses from one of the two exhaust ports of a single cylinder will drastically effect your emissions I want to know what youre smoking and why you arent sharing

 

One thing I haven't seen mentioned is that the can also catches water vapor from condensation when the engine is warming up on cold days.

 

That is an excellent point.

 

the OCD in me is now brainstorming on how to run lines... and that's just lines

 

I can't find my old water pipe but found a decent looking cheapy on ebay and ordered it... I hope I don't have any problem with all of the hoses and wiring of the can and other items that will hopefully be getting installed... I also hope that my wife doesn't freak out when she finds my stash of parts or the receipts for them.

 

This is why you need a "stealth" account w/ debit card, for purchasing performance parts. My wife is ever-vigilant of every box UPS or FedEx delivers to our house.

 

Just so I am clear because I am not totally aware of the proper names or abbreviations for things. I just bought a catch can and plan on routing a line from the metal fitting that many people attach a breather filter to when doing the DIY intake. That line will go into one fitting of the catch can, then the other line will go from the other fitting on the catch can to a fitting i am installing in my intake behind the maf sensor between maf and tb.

Is that a correct setup? or did i get something wrong?

 

Sounds about right. Something like this?:

 

Yes exactly!! Ok good im glad i had that right, i was worried i was planning it out all wrong.

 

Glad I could help!

I know you've noticed this TEO but for everyone else's benefit:

If you are running the catch can to include a hose from the PCV, a seperate one from the VC breather and a third for the hose to the intake pipe you will need to remember to cap the remaining hole on your intake manifold where the PCV used to go! Or you can use the port on the manifold to provide vacuum for the can and then just cap the port on the intake pipe.

Because now your PCV is attached to the can and then through the can to the intake pipe. Same with the VC breather. So now there is a port remaining on manifold where the PCV used to dump its blow by contaminants.

The can then seperates the air from the oil/water and keeps your sensors and engine clean. Or you can go really fancy and get a catch can for seperating the VC and PCV, and a third to match for your coolant overflow!

For anyone jumping in to the conversation late without reading everything: I do not advocate the T-fitting and in the pictures posted earlier, including my quick red/green MS paint job pic, in that configuration you are ONLY straining the air coming from the VC breather and then dumping it back to the intake pipe. This doesnt eliminate the PCV which goes to the manifold.

But even if you only running the hose from the VC breather to the can, it keeps your sensors nice and clean. If you leave the stock hose routing for the PCV, obviously that still dumps into the seperate stock port on the intake manifold.

On a turbo car you want to use the pre-turbo intake pipe for your vacuum fitting, on an N/A engine you technically can use either and I have seen both, like the stock Fit obviously, but at idle there will be far more vacuum at the manifold port (post throttle body).

So to sum up everything pertinent I've said in the last 4 pages:

There are several ways people will tell you about running a catch can.

Like I said originally on pg 1 & 2, I would not run a tee-fitting to join the PCV and the VC to one hose that runs to the catch can.

The two correct ways to do this:

Non-boosted:

• 1x line from the PCV
• 1x line from the Valve cover breather
• 1x line to either the manifold (post throttle body) or the intake pipe (pre throttle body, post MAF sensor)

Boosted:

• 1x line from the PCV
• 1x line from the Valve cover breather
• 1x line from the pre-turbo intake pipe

 

Ok so i just did a lot of my own research and read this whole thing over again. I think what I may end up doing is getting a second catch can to filter the "crap" out of the pcv line and it will be independent of the can i have attached to the vc/intake.

I think i will see the best results from this. correct me if I am wrong. Thanks!

 

Ok so forgive me for asking what may seem like a really dumb question. Does anyone have a picture of which hose is the PCV hose? I'd hate to use the wrong one and blow something up. I know someone posted a pic but it was very close up and to be honest i could not tell where it was. TIA