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Discussion Starter #1
Im on a mission to get the most reliability+clean engine bay. So for the PCV, is there anybody who is just venting the PCV valve to a catch can? Were talking NA Daily Drivers only. Emissions is not a huge deal here. I think the PCV valve is very restrictive, clogs easily and hurts performance/MPG.

I know at idle vac is high, and WOT vac is low. But say you ran from the black box, with very large rubber lines, to a vented catch can? Any reliability issues? And yes i have read EVERY PCV valve/catch can thread there is, but mostly its for Track/turbo cars. I want something for the NA Daily Drivers.
 

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It's not going to help your performance by anything significant enough to bother with a can. What it does do is keep your intake manifold cleaner. Shouldn't mess with reliability. Just follow the turbo catch can instructions for installation. It's the same deal.
 

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i recommend against it. I once had a car come in the shop making a constant chirp/chirp noise. Kicked my butt. i knew it was coming from the torque converter area but couldnt find it, swapped out the torque converter, the flex plate..nada. kicked my butt for 2 days.

finaly while the engine was running i happen to pop the dip stick out for no reason and it went pshhh real loud and hard, and the chirp went away.

stupid little filter on the breather port wasnt venting the crankcase pressure and it was escaping out the rear main seal.....

something to think about.
 

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I got a small air filter on mine at the moment like many others but I was told by Transzex "If you want your engine to last reconnect your PCV Valve" and I'm sure you know,he know's his shit.So I gotta reconnect mine.
Why not do both?
PCV tube -> catch can -> pcv valve -> intake
Cleaner intakes are nice
 

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R2.....Zap Balls
94 Ex coupe
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Mine is run to a single input vented catch can. It's been fine, but then again mine is boosted and the pcv doesn't work under boost anyways.
 

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I run my motor open-atmosphere. The pcv line from the block goes to atmosphere, the valve cover breather is open, and there's 2 extra nipples on the front of the valve cover that opens and goes to a catch-can that's vented to atmosphere. I think this is the best way to go if you have turbo, or a high compression motor. Keeps the oil cleaner and there's no blowby/oil vapors/fumes that go back into the motor. But you want to make sure that there's enough "outlets" on the motor so there's no abundance of pressure in the motor.
 

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Discussion Starter #10
any issue for reliability? i know it will keep the oil alot cleaner, im just worried about pressures and piston ring issues.

im also worried about suckin crap into the IM with the catch can, since my clear catch can looks like it has small bits of rubber in there, and its connected currently to the IM.

Also when i turn my car off, i can hear a HISSSSSSS for 2 seconds, which sounds like pressure is venting from somewhere.
 

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96 civic
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you got it backwards at idle vacuum is low and at wot vacuum is high.
 

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Discussion Starter #12
negative, vac is the highest at idle, at WOT there is very little vac. its been proven over and over again, hook up a vac gauge
 

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Resident Gunsmith & Duracoater
Ranger - work truck
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you got it backwards at idle vacuum is low and at wot vacuum is high.
no, YOU got it backwards.......

open throttle body = no vacuum, closed throttle body = vacuum

think of the throttle body as a form of resistance, will there be more force to draw air through a closed plate, e.g. vaccum, or negative pressure (given the atmoshpere around is positive, or 0 )

that is why you have a FITV, idle adjust screw, and an IACV to regulate the amount of air that bypasses the throttle body plate.

and still being able to run decently at idle.
 

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Discussion Starter #15
at idle, the throttle is closed, hence the engine is gonna suck through the vac ports on the IM, because the engine is always sucking, which is why its sometimes refered to as an air pump. When the butterfly is open, then it gets most of its air through the intake, and less suction from the ports on the IM
 

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97 Civic CX Hatch
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FWIW: I took a piece of tubing and went from the PCV to a T-fitting. Then I took the breather tube from the valve cover to another leg of the same fitting. Then, I took another piece and went from the T to an air compressor water filter. Then I took the output from that filter to the intake tube before the turbo. That way, pcv and valve cover always have a vacuum source, and the filter keeps out all the vapor, and whatever else from being recirculated. I used to get a lot of oil buildup in the charge pipes before I added this (and wrongly thought my turbo was failing), but now everything's clean as a whistle...no buildup in the charge pipes or intake mani. The best thing was probably that it only cost about $30 in parts...half of most other setups.
 

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Discussion Starter #17
i believe you have your setup flawed. THe breather filter sucks air in most of the time, its a 2 way system. If you were to hook up a tube and put your hand over the breather port on teh valve cover, it would be sucking in.

Ive done the whole homedepot compressor filter mod, but honestly the vapors and shit still get past the filter somehow, even with a steel filter inside the canister.


Ive seen alot of NA setups done with the endyn setup, and 2 nipples on the Valve cover which is connected to an open catch can, however i wonder reliability on a daily driver. I want to rid of the PCV valve since its so restrictive, and at WOT or high load, im sure its a huge bottleneck on evac'in gasses and pressure. But @idle its fine. Plus with all the vac ports sealed on the IM, i can feel better throttle responce. When the PCV valve cloggs, it kills performance, and it seems to clog alot, even when its installed after the catch can.
 

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D-series Janitor
Front Engine Dragste
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I am not sure really the deal with the PCV.

Mine (n/a, 10.25:1, d15b2, delta 260) doesn't suck in at all in the little tube going to the intake at idle. Does some at high RPM.

Left it unconnected for a pull on the dyno and made 0 more HP or torque.

Seems like a huge waste of time to me.
 

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97 Civic CX Hatch
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I have a small filter on mine since it pulls air IN as the manuals will show you. The one that puts it out is on the back of the motor near the oil filter. This one I had open for a while too, didn't make any difference other than the smell it gave off through the many holes in my firewall.
 
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