Effects of rerouting the PCV valve to a catch can?

[eclipse98GST]

Today I capped off the the intake manifold plug that went to the PCV valve and ran the PCV hose to my catch can. What are the effects that this will have? With my understanding i would think that by doing this the motor would not be sucking in bad gas vapors in turn allowing it to burn a more pure mixture of oxygen, please correct me if im wrong.

PS this car is an everyday driver 2G with a full 1G 6bolt swap.

 

[92awddsm]

If it is a dd, I would suggest returning the pcv valve to stock form. The fuel and oil vapor that is sucked up by the pcv is corrosive. It does more damage to the engine if not functioning than it does if it is functioning properly.

 

[illeffekt vr-4]

if its a street car run the pcv in stock form but you can put a fuel filter in between the pcv and manifold. that will keep your car running good but it will also prevent any oil from getting into the manifold. over time the filter will get dirty but they're only $3 so its not bad. the one on my car its still clear and i've had it for more than a month. hope this helps.

 

[eclipse98GST]

Use the SEARCH

I did search, Im no noob. I could not find the specific information that i needed, all i could find were posts saying how to do it but none that stated the effects of doing it. But thanx to this thread I ran the PCV valve stock again.

if its a street car run the pcv in stock form but you can put a fuel filter in between the pcv and manifold. that will keep your car running good but it will also prevent any oil from getting into the manifold. over time the filter will get dirty but they're only $3 so its not bad. the one on my car its still clear and i've had it for more than a month. hope this helps.

I would have done the fuel filter but there is absolutely no room, the hose that i am using is no more than 5" long, so if i wanted to run a fuel filter i would have to run another foot of hosing just to make it route correctly without kinking the hose.

 

[TSIfreek]

I have found it best to keep the pcv run in the stock form running a daily driven car. I tryed no pcv and found the oil getting black in 800 miles so its not a good idea on a DD.
At the track I wont use it but on the street yes.

 

[daren_p]

There have been many discussions on this subject but the short answer would be to keep it setup like stock for the DD. You can run a catch can inline with the crankcase vent to intake tube hose, just make sure its a sealed can & not one with a filter on it thats vented to atmosphere.

 

[gsxtacy]

Ill Effects?

Putting a AIR FLOW restriction in the PCV valve line will cause your dipstick to pop up when you go into boost, oil to sometime seep from your cap, and could cause other gaskets to leak....suck as your valve cover gasket, spark plug tube seal gaskets...ect...

 

[MyBeatGSX]

I've been running no PCV for 10,000 miles with no issues. The oil is just as clean as before and doesn't smell one bit like fuel or anything but oil. I don't have to worry about boost leaks, dirty intake air, popping dipsticks, burning oil, etc. Give it plenty of ventilation and you'll be just fine. I run 2 vent hoses to the ground just like cars ran for 100 years before emissions were invented. Works beautifully for me, I highly recommend it.

 

[daren_p]

I've been running no PCV for 10,000 miles with no issues. The oil is just as clean as before and doesn't smell one bit like fuel or anything but oil. I don't have to worry about boost leaks, dirty intake air, popping dipsticks, burning oil, etc. Give it plenty of ventilation and you'll be just fine. I run 2 vent hoses to the ground just like cars ran for 100 years before emissions were invented. Works beautifully for me, I highly recommend it.

So are you running your valve cover vented to atmosphere? If so, you don't have Dsmlink so you won't know but your g/rev will be effected by doing this. How greatly this will effect your tuning, its hard to say but when people are posting issues on the DSMlink boards the first thing they always make sure is that your valve cover isn't vented.

 

[MyBeatGSX]

How does a vented valved cover have even the remotest effect on grams/rev? Its in no way connected to the intake, MAF, engine in any way. It is its own system now, that's the beauty of it.

 

[zippyshoe]

I've had good success so far with the following oil catch can solution (on the breather hose), which may be found on the VFAQ's: http://www.tgilmore.com/talon/catchcan.html. However, instead of using the fuel filter specified in this link, I am using a Fram G2 fuel filter, sold at my local Wal-Mart for about $3. What I like about this solution is that its low-cost and that it has no effect on air-metering since it is air-tight.

 

[zippyshoe]

How does a vented valved cover have even the remotest effect on grams/rev? Its in no way connected to the intake, MAF, engine in any way. It is its own system now, that's the beauty of it.

When a breather filter is placed on the breather inlet of the valve cover, this creates a path for unmetered air to enter the intake manifold when the PCV valve is open. The air flows into the breather inlet, through the valve cover, through the PCV valve, and then enters the intake manifold without being accounted for my the MAS.

 

[MyBeatGSX]

I've been running no PCV for 10,000 miles with no issues ..... I run 2 vent hoses to the ground just like cars ran for 100 years before emissions were invented.

Maybe that will clarify.

 

[gsxtacy]

I use this nifty thing as a catch can,...I routed it back into the inlet pipe, and have had ZERO ill effects over the last 2000 miles or so...

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Good luck man

 

[zippyshoe]

Maybe that will clarify.

Whoops... In my haste, I missed the "no PCV" aspect of your setup. No air metering issues with that setup.

 

[SRiz]

ok well I have everything hooked up PCV wise except the hose that goes back into the intake is just a open air filter..... I know im venting metered air... when I get my ECU+ can i compensate for this or will it always be a problem

 

[2gtalonman]

Mine came with a small filter on it that leaks oil, I think im gonna have to do this fuel filter mod. My questing is where does the other hose go? the intake tube?? if so I dont have a insert on mine its hard pipe with O/A with a 3'' gm maf >!>! what can I do?

 

[zippyshoe]

Mine came with a small filter on it that leaks oil, I think im gonna have to do this fuel filter mod. My questing is where does the other hose go? the intake tube?? if so I dont have a insert on mine its hard pipe with O/A with a 3'' gm maf >!>! what can I do?

The other hose normally connects to the intake pipe. The key is that you want this hose to connect to a source of metered air. In the factory configuration, the intake pipe is an acceptable location since it is after the MAS.

 

[zippyshoe]

ok well I have everything hooked up PCV wise except the hose that goes back into the intake is just a open air filter..... I know im venting metered air... when I get my ECU+ can i compensate for this or will it always be a problem

I believe you would be hard-pressed to "tune-out" this source of unmetered air. This path for unmetered air is not always present - it only exists while the PCV valve is open. When the valve is closed (such as while under boost), this pathway is blocked and air metering is now accurate.

 

[RoasT BeeF]

I've been running no PCV for 10,000 miles with no issues. The oil is just as clean as before and doesn't smell one bit like fuel or anything but oil. I don't have to worry about boost leaks, dirty intake air, popping dipsticks, burning oil, etc. Give it plenty of ventilation and you'll be just fine. I run 2 vent hoses to the ground just like cars ran for 100 years before emissions were invented. Works beautifully for me, I highly recommend it.

Same here. I removed my pcv valve long ago. No problems.

I hope everyone realizes that the pcv valve is a source for boost leaks. Those things dont hold much pressure before you are just blowing air past it straight into your valve cover. Not a good idea.

 

[92awddsm]

If you are using a non-factory airflow sensor, then you would need to plumb this hose somewhere after your particular airflow sensor to preserve proper air metering.

This isnt possible for those of us running a gm maf in blow through configuration. If I hooked my vc vent tube after my mas, the crankcase would see more pressure than it would with a faulty pvc valve.

 

[2gtalonman]

The other hose normally connects to the intake pipe. The key is that you want this hose to connect to a source of metered air. In the factory configuration, the intake pipe is an acceptable location since it is after the MAS. If you are using a non-factory airflow sensor, then you would need to plumb this hose somewhere after your particular airflow sensor to preserve proper air metering.

I only got about 4 inches a pipeing befor the 2g elbow I'm suppose to plump it in after the gm maf?? can I do it to the top of the TB wear the emissions used to be?

 

[Black95TSIawd]

There is so much misinformation in this thread its not even funny.

If you vent your nipple off the VC with a small filter or even to the ground with the pvc still connected to the intake mani, then you'll have problems with unmetered air being sucked back in and then into the intake mani. The proper way to disconnect the pvc system, the way i've been running for over 10,000 miles with no ill effects, is 1) firmly have the nipple on the intake mani covered and leak free then 2) screw a free flowing fitting into where the stock pvc valve is(i modifed a stock pvc valve to be free flowing) followed by 3) unplugging the other vacuum line off the VC from the intake snorkel and finally 4) running both lines to the ground if your cheap, to an uncapped gatorade bottle if your ghetto, or a true ventilated oil catch can.

This allows no unwated air to enter into the engine all at the same time providing better ventilation of crank-case pressure. IE your dipstick will probably stop popping out now if it did before. Now enjoy having a healthier breathing motor.

I only got about 4 inches a pipeing befor the 2g elbow I'm suppose to plump it in after the gm maf?? can I do it to the top of the TB wear the emissions used to be?

You have to run it pre-turbo. Otherwise you'll be pushing boost into the VC instead of sucking it out.

Mine came with a small filter on it that leaks oil, I think im gonna have to do this fuel filter mod. My questing is where does the other hose go? the intake tube?? if so I dont have a insert on mine its hard pipe with O/A with a 3'' gm maf >!>! what can I do?

Be careful with the fuel filter mod. Always check it to make sure it isn't clogged up.


Just an FYI to those keeping tabs on this thread, i went through three pvc valves before switching to my current setup posted above. Why? They all leaked when doing boost leak tests. I havent tested an OEM valve, but a generic one is a no no in my eyes.

 

[MyBeatGSX]

This is amazing.... I'm actually getting support and agreement this time around...

 

[SRiz]

how did you modify your stock PCV to be a stright through fitting... im sick of blowby and im gonna run both lines to the ground after I figure this out