Could you mock up a drawing for a single can FI set up?

Ive always been a little confused as to how I should have everything routed.... I dont burn any oil... no oil in the intake (that I can tell).... I run a AMW can right now and never seems to accumulate more then a couple drops here and there.

Thanks.

 

Except that his filter is connected directly to the inlet side of the turbo making it difficult to plumb a line in that location.

 

Here is a diagram of the proper function of the PCV valve:


Here is how the LS7 dry sump C6 Z06:


Oil in the intake belows on a brand new C6 Z06:



And the intake manifold:



FI showing inline checkvalve to prevent boost pressure from entering intake:

 

If the vacuum source is past the throttle body, how does oil end up in the baffles that are in front of the throttle body? Something just insn't right with that picture. I'm not doubting it, just baffled by it. I recently pulled my FAST and upon opening it, I saw puddle oil inside it. I have a catchcan with the baffles in it and all, and collect a decent amount, but I'm just baffled how much oil gets pulled into the intake.

 

Depends on the can...is it a full 1 qt? Or a smaller one. If you have excess crankcase pressure & blow-by the smaller cans will saturate quicker and still allow a small amount to be pulled through....but that is an internal motor issue being the culprit causing that. Also, if there is an issue causing blow-by, then no can can prevent oil entering the intake.

Another area of ingress can be bad or damaged valve stem seals which will allow the reversion pulse to pull & push oil from one runner to another (like when an intake valve drops in 1 cylinder but you find pieces in all of them & pieces embeded in a composite intake manifold. A intake valve not sealing perfectly also allows excess pulse back into the intake runners and if any oil is being pulled past the rings it will end up as a mist in the runners as well.

 

I guess I can either drill and tap a spot on the end of the filter or buy a small piece of piping to drill and tap there. Then how would it be routed?

 

Like this:

 

Excelent diagram. Only thing missing is a filtered frsh make-up air source while under boost (the main air filter will provide it when not in boost). Just add a breathered oil fill cap & that is the correct system for forced induction. I also add a checkvale before the filter so under boost no oil is pushed through into the air filter.

 

Under boost this becomes a vent, not a clean air source, because of the opposing pressures on both sides of the PCV valve. See my comment below.

I assume your talking about a one way check valve in the clean air line. I don't agree; lets say you have a problem with blow by that deposits oil into the compressor inlet from the clean air line, pretty common problem. Stop and remember how and why the PCV system works. Engine vacuum (negative pressure) opens the PCV valve, and draws the ventilation supply flow, i.e., metered air, through the engine and into the intake manifold. Now, in forced induction applications, the intake manifold will be under vacuum only at very low RPM's. Most of the time, the intake manifold will actually be under boost and therefore under positive pressure; therein lies the problem. Even though the PCV will open under positive crankcase pressure, that positive pressure created in the crankcase is acting against a greater or equal positive pressure in the intake manifold.

When both sides of the PCV valve are at the same pressure (pressure is acting on opposite sides of the diaphragm), there will be zero flow because the PCV valve can’t open. That means that you’ve now positively pressurized the crankcase. Under this condition, the PCV system has to act in reverse. The flow and pressure is vented the wrong way through the clean air line over to the intake inlet. This is the point where one theory recommends the use of a one way check valve.

The theory is to orient the one way check valve to allow flow into but not out of the crankcase. While that might be acceptable on a really tight engine, the fact is that most forced induction engines run a fair amount of blow by. The problem with a one way check valve installed in the clean air line is no path exists to vent the blow by, there by pressurizing the crankcase. The only path to relieve positive pressure is around seals and gaskets. This in turn causes them to leak and greatly impacts performance because of the pressurized crankcase.

So, back to the the comment at the top.....By installing the valve cover breather filter one creates a vent for the pressurized crankcase. Remove the one way check valve from the clean air line, cap the valve cover, and the clean air line is now the vent. Introduce a second catch can without a one way check valve into the clean air side and the best of both worlds are realized.

Using the RevXtreme catch cans, the dirty side can would have a one way check valve and the clean side can would be the same design without a one way check valve.

 

I've added additional info to the diagrams based on the many questions I've received. See diagrams below, pick the one that matches your valley cover/engine configuration:

 

haha... posted a few mins too early....

my setup is closest to your last figure, but wouldn't the "dirty side" just get blocked off under boost making the "clean side" just another "dirty side?

just trying to clear a few things up... thanks for the figures!

 

Yes, under boost conditions in 'loose' engines the crankcase pressure could equal manifold pressure causing a 'zero flow' condition which pressurizing the crankcase. The only pressure release paths are seals/gaskets and the clean air side of the PCV system.

So, the clean side is used as a vent for excessive crankcase pressure like the dirty side does. The key is a sealed system. The engine will do a better job of evacuating the excessive pressure by routing to the intake than the atmosphere will, why not utilize it.

Concerning the port on the throttle body, on a forced induction application this is the pressurized side of the intake. If you hook this to the valve cover you will be pressurizing the crankcase which you don't want to do. Blocking the port at the throttle body is correct for your application. Keeping the clean and dirty sides separate and rerouting the clean side to the filter inlet will allow you to use engine vacuum to help evacuate crankcase pressure.

 

I'm going to order a saikou michi catch split dc3 and do the last setup that you are suggesting for turbo applications. Is the only way to order them is through there site or is there a sponsor on here that sells them?

I'm curious why people use vented catch cans or put a breather on the valve cover. That opens the system. It either needs to be completely closed or completely opened with nothing going to the intake, otherwise the crankcase is pressurized.

Lot of good info in here. Thanks again for your time!

 

sticky material!

 

You have to order the Saikou Michi direct from him. If you want something custom, send him an email. For your application flow is critical, so I would look at the stage 2 cans with the required hose barb sizes.

What I have found is that most don't really understand how and why the system is there. Add the multitudes of possible configurations and conditions and total confusion reigns.

 

thanks for the info man, i deleted my other post so there wouldnt be any confusion with all the diagrams... lol

 

Aaron... thank you very much for those drawings. I see that I may not have mine set up for optimum performance.

I hope its not too much to ask, youve done a lot so far, but I have a boosted application and before I added the SC to the mix I installed a LS6 valley to my LS1. With that said could you make one more schematic for a LS1 thats boosted, single can, with LS6 valley.

Im going to draw out the set up I have in mine right now. Be back in a bit with my layout.

 

I sent them an email, haven't heard anything back. I'll be getting the split Dc3. Hopefully this fixes my issues and my motor isn't hurt.

 

On a FI application the intake manifold is ONLY pressurized when the turbo/SC is in boost. Just look at the boost gauge when driving....this is only when under heavy acceleration, most of the time when driving you are not under boost so the system IS getting vacume (unless your one of the few that only runs wide open 90% of the time).

The only thing I disagree on with your setup is that you leave an access route for oil mist to enter the turbo. Use a breathered oil fill cap and in the event you have excess crankcase pressure it will vent through the breather. The rest of your design is fine. Understand, this is what I do day in & day out.....at any given time I have 2-3 or more FI builds in the shop, and I don't care to have any ingress poit for oil into the intake air charge.

 

Post updated with additional diagrams.