Quick question on catch can

[number1olddog]

Two days ago I had my mechanic buddy install a mishimoto catch can on my PP ecoboost. I read somewhere that certain models have a pressure relief valve and I want to make sure I don't need anything else that should be installed with this unit for it to work properly. Thanks

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[Yellowboost]

Two days ago I had my mechanic buddy install a mishimoto catch can on my PP ecoboost. I read somewhere that certain models have a pressure relief valve and I want to make sure I don't need anything else that should be installed with this unit for it to work properly. Thanks

If you got the kit you should be fine, there is an optional breather but not required. Just don't let the can get all the way full.

 

[jbailer]

I think you're talking about the check valve some people with the UPR CC were getting or if they gutted their PCV. Nothing to worry about with the Mishi.

 

[LuckyJerk]

Yea I agree with Yellwoboost and Jbailer you don't need to gut the PCV.
Even if you get the UPR like I have you don't need to. The reason for gutting the PCV is to fix a smoking issue.

 

[Multiplexity]

My only thing about the catch can is if you bought it specifically for the smoke issue then it wont help. I naively bought it for that purpose and it didnt clear the problem. Im looking into getting upr dual valve separator now. I have a 2015 so maybe its better on the 2017.

 

[Yellowboost]

I have a 2016 with the upr dvcc and I have the blue smoke issue after a short idle time.

 

[Marvinmadman]

2016 with gutted PCV and UPR DVCC and Breather. Fixed my smoke at idle after the downpipe was installed.

 

[MiDiablo]

[ame]

^ use this video to learn how to gut your PCV.

I ran the UPR DVCC on my car w/o the PCV gutted and the car would smoke from time-to-time (minimally) w/the Catless Downpipe on it.

I've installed quite a few of the UPR DVCC on cars that either smoked a little, or in some cases they cleared out the entire street, and it has helped considerably (especially after replacing an incorrectly installed Mishi unit).

 

[jbailer]

I'm not questioning it, just don't understand. Can anyone explain the need to gut the PCV and why it helps with the smoking issue? All the PCV is, is a check valve like the one that UPR includes in their line correct? So you have the factory oil separator in place either way gutting the PCV is just moving the check valve to after a second oil separator (the dirty side CC) right? How does that reduce or eliminate smoking? The dirty side can is still in place even if you don't gut the PCV.

All the PCV is doing is controlling air flow. Seems like there would be no difference having the second check valve (PCV) in operation. Again, please don't think I'm questioning it or challenging it, I'm just trying to understand why even do this?

 

[Marvinmadman]

One less restriction.

 

[jbailer]

One less restriction.

I don't understand how that could eliminate or reduce smoking. The PCV (check valve) just keeps the air in the crankcase until the vacuum from the intake draws it out if there's a pressure difference, the PCV allows that and does the same thing the check valve in the line does. The only difference is having 1 check valve instead of 2 that are doing the same thing. Is the problem the intake can't operate both check valves and the oil/vapors left in the crankcase is what's causing the smoke?

 

[bam88]

The stock PCV is very small and restrictive not allowing for much airflow. Vacuum airflow is required at idle to be able to suck out the positive crank case pressure that causes the smokey turbo.

 

[jbailer]

The stock PCV is very small and restrictive not allowing for much airflow. Vacuum airflow is required at idle to be able to suck out the positive crank case pressure that causes the smokey turbo.

So it's a volume issue? I guess even with the valve open, the air having to work around the open valve is too restrictive and I guess the CV in the UPR line is larger and more free flowing? The smoke symptom only comes from leaking seals after too much crankcase pressure though right? Just trying to figure out where the smoke comes from. Then I guess when people install the UPR DVCC, the reduced CC pressure relieves the stress on those seals and they don't get the smoke?

I'm still at stock boost and have never had a problem. I'm wondering if it's only an issue at higher boost levels getting more blow by? Maybe as my rings wear, I'll get more blow by and eventually have the same issue.

Still curious if anyone at stock boost levels ever gets any oil in their clean side CC. It seems like you could do the same thing with a CV on the other side of your dirty side CC and gut the PCV the same way right?

 

[Marvinmadman]

Mine smoked at idle after the DP with the stock tune. No high boost here.

 

[bam88]

Oil is getting into the exhaust is where the smoke is coming from, it appears there is no real conclusion as to where it comes from but my bet is turbo oil seal. There have been reports of completely stock cars having a smoking issue. Typically once airflow through the turbo is increased (mostly on the exhaust side) is when you really throw the dice. The unique design of the UPR DVCC allows for the most amount of vacuum to help reduce pressure in the crank case. Personally I would not bother with a clean side catch can as the UPR DVCC will do the great majority of the work. I highly suggest a dirty side catch can for all DI motors, not just for smokey people.

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