driver side catch can no fluid

[mmakam2]

Hey guys so I had JLT catch cans both driver and passenger but I sent them back because the driver side hose inner diameter was smaller than stock. I then installed Ford Performance catch cans on both sides.

When I had the JLT cans, both sides were catching fluid, more on the pass side but still a good amount on the driver. With the FP cans only the pass side is catching fluid. The driver side was bone dry.

Anyone have experience with FP catch cans and see fluid on the driver side? I probably wouldn't care but it's weird because I had the JLT cans on for less miles and I saw a good amount of fluid on the driver side.

I had a boosted rb25 car with a catch can with too small diameter lines and it caused too high of oil pressure that my turbo was burning oil from the seals. Went away after increasing the line size so I didn't want to risk it on the voodoo even tho more than likely it would be fine.

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[datadatum]

I never see oil on the driver side, using the FoMoCo AOS. Only the passenger side. I believe this is fairly common.

 

[fpGT350]

I only have the passenger side separator installed and it only captured about 2 ounces in over 2,000 miles of driving.

 

[sox3]

Same for me, 0 on Drivers side do far with ford seperators

I never see oil on the driver side, using the FoMoCo AOS. Only the passenger side. I believe this is fairly common.

 

[Tomster]

And that's why most just get the passengers side can.

 

[G8rbcn]

I only have had oil on the driver's side FoMoCo catch cans. Maybe 3oz in 5,000 miles since I installed them.

 

[Tomster]

I only have had oil on the driver's side FoMoCo catch cans. Maybe 3oz in 5,000 miles since I installed them.

I think you meant passengers side?

 

[mmakam2]

Yea that's what doesn't make sense to me. The Ford one didn't catch anything but the JLT had a significant amount.

Update: Specifically talking about the driver side.

 

[FLATPLANE]

I Have JLT Catch Cans Drivers side always empty

 

[mmakam2]

Anyone know why there is less fluid in the drivers side anyways?
I had the JLT on during the first 1000 miles of break in so maybe that's why I caught some fluid and it stopped.

 

[JAJ]

Anyone know why there is less fluid in the drivers side anyways?
I had the JLT on during the first 1000 miles of break in so maybe that's why I caught some fluid and it stopped.

The crankcase ventilation system is set up to flow fresh air into the engine from behind the air filter on the driver's side and pull crankcase gas out of the engine and into the intake manifold on the passenger's side. The driver's side connection is just a piece of hose that connects from the air intake duct ahead of the throttle body to the crankcase. Crankcase air is drawn from there for two reasons - first, it's been filtered so it's clean, and second, it's been measured by the MAF sensor so the ECU knows the air is in the engine somewhere.

The passenger's side connection has a one-way valve with a flow restriction in the fitting on the valve cover connected to a hose that goes straight to the intake manifold, which, most of the time, is under vacuum. Virtually all of the oil-laden crankcase air flows through that hose, so that's why the pax side catch-can gets the most oil.

The only time that there might be airflow from the crankcase via the driver's side connection is at full throttle, when the intake manifold vacuum is greatly reduced - it's not zero, but it's close. In that situation, any blowby gas will leave the crankcase via the easiest route; the bulk of it will go to the intake manifold anyway, and any that doesn't go that way will go via the driver's side connection and join the intake airflow ahead of the throttle body. When this is happening, the driver's side catch can can collect oil. But, if you have a particularly tight engine that doesn't produce a lot of blowby, then there won't be enough airflow to reverse the flow on the driver's side and you'll still get nothing on that side. I ran one for three years and took it off this year because it was always dry.

 

[mmakam2]

Yea on MAF cars its very important to make sure all the air going into the motor is metered. I've seen a lot of coyote forced induction builds where they just put breathers on the valve covers instead of catch cans. I wonder if these people know they are screwing up lol..

Edit: actually now that i think about all the air is still metered, the gases leaving the motor don't matter. forget what i said, immm stupid.

 

[Mountain376]

Yea that's what doesn't make sense to me. The Ford one didn't catch anything but the JLT had a significant amount.

Update: Specifically talking about the driver side.

You have a glass full of Coke in front of you. To drink it, you have two straws: one small diameter and one large diameter. Catch is, you can’t dip the straw into the Coke, you can only let the straw get within a few MM of the surface of the Coke.

Which straw is going to allow you to “suction” the Coke up easier?

 

[mmakam2]

You have a glass full of Coke in front of you. To drink it, you have two straws: one small diameter and one large diameter. Catch is, you can’t dip the straw into the Coke, you can only let the straw get within a few MM of the surface of the Coke.

Which straw is going to allow you to “suction” the Coke up easier?

this makes literally zero sense to me.

 

[Mountain376]

this makes literally zero sense to me.

Lol.

I'm trying to illustrate what the small ID hose of the JLT catch can is doing vs the larger/to-OE-design one of the FP catch can. You can't just throw a hose on, regardless of size, and have it work properly.

The smaller ID hose is likely pulling a higher and quicker vacuum at the inside of the hose, and pulling more oil vapor/causing the ability to pull oil vapor into the system.

At WOT, intake pressure increases, manifold vacuum drops and turns into a pressure pressure environment - it's possible to setup enough of a vacuum in the clean-side of the PCV system to pull oil vapor in from the crankcase/valvetrain area (especially when you have high RPM and more blow-by occurring).

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