fonseca

That price doesn't suprise me Redz, seems like the better ones are costly, and the ebay knockoffs haven't quite caught up yet. But it's only a matter of time. . . wink1.gif

Airborne, isn't that metered air you're venting, or is it different with MAP? I'm guessing you're MAP, don't see the sensor on your intake. With a MAFS I know it can affect your A/F ratio.

I just can't understand the benefits of not recirculating in any case. Think of the poor cute animals choking on your fumes! laugh.gif

Airborne

I converted to MAP almost a year ago wink1.gif

Recirculating is just a way to get around MAF sensors. You don't lose or gain anything from it. Your car can make cooler sounds with an atmospheric BOV fing02.gif

LarryMcFly

PCV only makes sure that fumes don't go in the IM while it's not under vacuum.

Lines going to the catch can don't have to go back.

The simple/effective setup is to:

Remove the pcv valve (since it's not connected to the IM, there will never be vacuum to open it.)
Run both lines to the catch can
Put a filter on top of your can.

This way, all fumes will go directly to the can, there won't be any fume pressure in your head and no oil residu in your intake/IM.

If you insist on running lines back to the intake for some xyz reason, don't bother using a catch can, just get an oil seperator.


Fonseca, the fumes decrease the octane in your fuel mixture which can cause problems.

1997tibby

I've been wondering this recently as well, seeing as i'm going turbo now, and wasnt quite sure cause i dont have anything connected to the intake system (like stock) and i dont have a catch can....so i was thinking on how it works, and at the time it made sense...doesnt quite make sense to me right this moment though....hrmmmm.....anyways what i did was just run the hose off the PCV valve and loop it to the breather next to it...similar to the coolant bypass on that throttle body!!!! Ok now i remember...the pcv valve needs air sucked out (was connected right to stock manifold in front) and the breather pipe next to it that was connected to the intake elbow (sucks air out) so I looped them together the PCV valve air gets sucked into the breather pipe! atleast thats my logic...and running my car N/A for 2 weeks before the turbo didnt notice any damage or problems.... lmao.gif was lucky if its not a good idea still have it hooked up that way................ does anyone agree or dissagree? maybe clear up my logic and learn me somthing?

LarryMcFly

Looping them together = no exit for the fumes = pressur buildup in the head = NOOOOO

Both hoses serve the same purpose. One is for high load (the one with the pcv), the other for low load.

Both serve an environmental purpose ONLY. If it was not for that, they would simply go to a can or on the ground.

Having those fumes in your intake system will be the equivalent of a decreased octane figures (oil fume increase the risk of predetonnation) and it gums up your system.

When you install a catch can, you route both hoses to your can. The filter on top of the can (breather) is there to let the pressure out while keeping the oil from getting everything around dirty. You also need to remove the pcv valve because if you leave it there, it won't open on vacuum, only on pressure from the head. Might as well remove it and keep 0 head pressure.

There is NO need to route the hose back from the can to the intake has the engine doesn't need it.

Hope this helps.

fonseca

I did some searching and found this catch can FAQ. It seems to conflict with some of the statements in this thread, and in fact it affirms what I have always been told in the past, and you usually see these points brought up in CC threads on other car forums.



So are #1 and #4 incorrect?

This pdf linked on that page explains PCV systems in a concise manner.

REDZMAN

So, this weekend I'll give THIS a try.

1. I'll route both lines to my catch can.

2. I'll put a breather filter on the return fitting.

3. I'll cap off the 2 ports going into the intake (Elbow and IM).

Then I'll run it for a bit and see if there's any problems. If not, I agree, it should be done this way.

LarryMcFly

Don't forget to remove the pcv valve. You have to unscrew it and screw a fitting in the hole to hook up your hose.

#1 There is no pressure buildup has it is an open system. Remove pvc to allow both holes to evacuate fumes.
#2 Not at all, all the oil is in the can instead of being burned
#3 Not at all, unless the can has a leak or it is so full as to drip from the breather
#4 Oil vapors are not "metered air". What goes through th eintake system is.

I have been running like this for over 90 000km, so far so good wink1.gif

REDZMAN

Remove the PCV Valve, Check.

LOL

Any idea what size fitting I need for that folks?

fonseca

I know there's no pressure buildup, we have a negative pressure system that draws gases out. And I believe it is metered air because the blowby contains unburnt fuel as well, which will get burned once it is recirculated, thus improving fuel economy.

I've wasted most of the evening reading, and everything I can find suggests that vacuum on the lines draws out the vapors, and without this vacuum you can get sludge buildup in the valve cover. Maybe you can take some pics of yours the next time you have it off, without running any cleaners beforehand.

I'd like to be convinced that you're correct, that would let me run one catch can instead of two.