breather/PCV system for turbo engines - Lateral-g Forums

wedged · #1 10-22-2009, 03:32 PM

Lets see what every one has done for oil vapor control on turbo engines.

**camcojb** · #2 10-22-2009, 03:56 PM

I run two #10 breather lines out of the top block plate behind the intake (LS2). I used Stefs breather tanks hidden inside the inner fenderwells, on the firewall. They are not visible once the fender is installed. I have a drain line with a petcock on the bottom that runs down to frame level in the fenderwell, so I can remotely drain or check the level in the tanks. There is a breather cap on each with a 1/2" nipple, and hose running through the fenderwell and connecting to my air filters for the turbos. This directs the vapors back into the engine, eliminating the smell.

One important thing that you must have is good baffling from the top plate, valve covers, or wherever your breather lines exit the engine. If not it will push oil into the tanks and fill it pretty fast with oil. I built this from thin plate aluminum to baffle the area I pulled the vapors from under the top block plate of my LS2. I ran the lines hidden so you do not know the tanks are there.

Jody

GM Muscle · #3 10-22-2009, 05:05 PM

i will try to nab some pics but on my bosses fox body 302 we basically used
-10 off of the front of both covers to a "T" and a pcv back to the bottom of the intake. then on the lifter valley side we used a supersnake electric vacuum pump with a breather and tank. it works really well. only small puff of smoke after letting off of full throttle.

wedged · #4 10-23-2009, 06:34 AM

Jody-from your description, you have no vacuum source connected to the breather system, other than a final return to the intake tract ?

**camcojb** · #5 10-23-2009, 09:55 AM

Quote:

Originally Posted by wedged

Jody-from your description, you have no vacuum source connected to the breather system, other than a final return to the intake tract ?

correct, just the fume pull into the air filters, no direct vacuum. Mine is set up as a breather system for any excess pressure to have a way out, not a pcv type system. If you do a manifold vacuum pull you'll need some very good oil separators in the system also. Even with the best aftermarket oil separators I've always had some oil sucked back through as even the oem systems do. Oil in the intact increases the chances of detonation so I go this way and eliminate that issue. Plus the intake is under pressure with boost so any vacuum line to the engine is as well. The air filter hookup under boost should pull some pressure, and it definitely increases pull under boost instead of the opposite with a manifold vacuum source.

wedged · #6 10-24-2009, 08:09 AM

Thanks for clarifying. I've just got it stuck in my head that I HAVE to have a PVC valve, mean while on my car I've got an exhaust evacuator system and no PCV. Right now I've got my NA efi'd 440 in the truck set up with a filtered breather on one v/c and pcv valve in the other. I planned on using a baffled grommet for the PCV, but did find one that would fit, so it's in there unbaffled right now. As you can imagine, it pulls quite a bit of oil. It sounds like your set up might be the ideal way to go.

E.rodz · #7 10-24-2009, 10:47 AM

I used a catch can from Mike norris motorsports it is very high quality with a filterd top and a drain on the bottom.worked great for a supercharged application.i found some great routing info on ls1 tech.

**GregWeld** · #8 10-24-2009, 12:03 PM

I'm running big stroke - small case - with NO vacuum - engine.... so have breathers in both valve covers with K&N filters... and a plumbed hose to a baffled tank and breather - from the FUEL PUMP BLOCK OFF PLATE. Since I'm running electric fuel pump -- and the push rod hole is in the bottom of the block ( side actually - and runs UP at an angle to the cam). This takes the "pulses" from the bottom side of the engine - and puts them into the catchcan. I have A LOT less fumes now from the top end breathers. A LOT less!

I've yet to have any oil "accumulate" in the catch can. It's only "vapor" traces that have collected so far... and I run it A LOT and HARD.

EEEEEEEEEEHHHHHHHHHHAAAAAAAAAAAAAA!!

**camcojb** · #9 10-24-2009, 01:01 PM

Quote:

Originally Posted by GregWeld

I'm running big stroke - small case - with NO vacuum - engine.... so have breathers in both valve covers with K&N filters... and a plumbed hose to a baffled tank and breather - from the FUEL PUMP BLOCK OFF PLATE. Since I'm running electric fuel pump -- and the push rod hole is in the bottom of the block ( side actually - and runs UP at an angle to the cam). This takes the "pulses" from the bottom side of the engine - and puts them into the catchcan. I have A LOT less fumes now from the top end breathers. A LOT less!

I've yet to have any oil "accumulate" in the catch can. It's only "vapor" traces that have collected so far... and I run it A LOT and HARD.

EEEEEEEEEEHHHHHHHHHHAAAAAAAAAAAAAA!!

slick setup for a n/a engine, but with forced induction that would not work the same......

**GregWeld** · #10 10-24-2009, 01:24 PM

I was wondering about that Jody... you guys have quite a bit of "blow by" with the cylinder pressures you're running?? Would it just blow past the rings and create too much crankcase pressure to have it be "passive" like this (mine)?

I love these forums for exactly this kind of stuff - learning by osmosis...

:>)