Engine pvc valve--> air breather?

sorry for the noobness but what is the pcv? is it the tube from teh top of the engine to the throttle body? cause if it is i might already be your guniea pig....

pvc valve--> air breather?

can you replace the pvc valve witha air breather? ('96)

why would you do that? breathers = lose hp

actually, you can be our ginny pig! j/k! let us know how it goes!

yeah thats what it is.
i just wanted to know if you can do it or not, since i saw it on a civic i was curious.

and no david, i wont be your ginny pig! LOL

actually people with turbochargers do it all the time. don't really see why you would if you didn't have forced induction though.

ehh just looks on the engine bay thats all.

So, I never really stopped to consider the PCV system in depth until now.

There are 2 tubes that run from the top of the valve cover to the intake. The breather hose is the one on the front and runs directly from the head to the throttle body (connects BEFORE the throttle plate). The PCV hose comes out at the right side of the valve cover (US driver's side) and goes through the PCV valve (which is actually threaded into the valve cover) and connects directly to the intake manifold (after the throttle body).

On the '03 1ZZ (and most likely previous 1ZZ's and other Toyotas), the PCV valve is apparently a pretty big component in air/fuel ratios and driveability. It's factored into the ECU programming for the a/f feedback control system. Considering that 70% of blow-by is fuel vapor, the PCV is another source of fuel for combustion when it comes right down to it - like the EVAP system. So, putting a PCV filter on and removing the PCV tube from the manifold would just hurt performance and driveability. The breather hose filter would be ok, but not the PCV hose.

Late,
Trav

^^actually the breather line and the pcv are set up differently on 93-97, than on later models..

PCV vapors polute clean intake air.. not make it better
the only reason pcv exists is for emission control

huh? don't follow you here....

Trav

i always wanted to post asking what exactly the pcv valve does and if it helps or hurts but i didnt wanna be the noob to bring it up. any body have some real statistics on this subject?

http://www.autoshop101.com/forms/h63.pdf

if you want all the details go read.

Let me try to summarize the main issues.

Purpose of the PCV system
A small amount of gases in the combustion chamber escapes past the piston. About 70% of this gas is unburned fuel that can contaminate the engine oil, cause corrosion to critical parts, and contribute to sludge build up. When the engine is under load (accelerating, no vacuum) blowby gases increase crankcase pressure and can cause oil leakage from the engine. The PCV system removes these gases from the crankcase.

On MAF sensored vehicles (like 00+ Corollas) the ECU fuel calibration takes the PCV system into account. This is important because the PCV flows different amounts of air under different loads. Unlike what you might expect, the PCV flows the least under vacuum and the most under WOT acceleration. Why? Because during WOT the engine produces the most blowby.

Ok so now let's discuss replacing the PCV valve with a breather filter. This is problematic because of a few reasons:
-The fuel-rich blowby gases aren't being sucked into the manifold and start contaminating the oil and all that bad stuff I said before.
-The engine air/fuel calibration is messed up because the gases from the PCV system aren't going into the engine any more.

But why do turbocharged people do it?
-Because the PCV system won't work with a boosted car anyway (the boost pressure is just going to constantly close the valve)
-A lot of other people do it and most people don't care about leaving it open to the atmosphere.
-We change our oil so often contamination isn't an issue.
-We use our own fuel calibration so the ECU thing isn't an issue.

On a side note, I think the best way to address this for turbo'ed people is to leave the BREATHER HOSE open to the atmosphere (or use a breather filter), and leave the PCV hose connected to the manifold. At least under vacuum the PCV can suck the blowby gases, and under load/boost the blowby can go into the atmosphere out the breather filter.

Ok, I hope this answers everyone's questions. Does having a cool looking breather filter there instead of the PCV outweigh the cons? It's up to you. Will performance suffer that badly? Probably not. Is blowby that bad for the oil? Hard to say.

Anyway, why would you want to put the filter on the PCV hose and not the regular breather hose? I think some of you may have these 2 confused.

well im definatly all worried now can you take a look at some pics and point out which is the pcv and which is the breather? I have a 05 corolla so i had to make a few compromises when i oinstalled my cai
thanks

http://groups.msn.com/iliksprite/ca...to&PhotoID=1381

you're going to have to take off oyur engine cover and take a better picture so we can see where that breather is connected to

actually come to think of it...I have a breather on the engine side of mine...which is right I know ....I have the manifold side capped off...is that right?

system, as long as the crankcase has some way to vent you should be fine.

cap the manifold, put a breather filter on the valve cover breather port, leave the stock pcv hose in place. the pcv valve (basically a check valve) will close under boost, and open under vacuum, so at least under idle you got some fresh air circulating through the crankcase.

it's easy.
the breather hose connects the valve cover to the FILTER SIDE OF THE THROTTLE BODY. It's fine to put a breather filter at the valve cover here.

the pcv hose connects the valve cover to the MANIFOLD. also, connected to one side of that hose is going to be a plastic pcv valve. it may be attached to the valve cover. leave this one alone.

on a side note. most cars have a hose connecting to the AIR HOSE. this is the EVAP FRESH AIR SOURCE. most cold air intakes have a port for this purpose. TURBO PEOPLE TAKE NOTE: do not connect this hose otherwise you are PRESSURIZING THE CHARCOAL CANISTER.

yeah I just wanted to make sure I was supposed to cap the mainifold side....mine perfect then...thanks.

I just left mine open with no hose connected to it or nothing....seems work pretty good...I was thinking of running a line from the EVAP to my air inlet tube so it can be filtered. I don't know if it matters.

"-We change our oil so often contamination isn't an issue."

i had a breather on for a short time but decided against it.

the way you set it up is fine. if you're worried about something getting in there just use a piece of pantyhose or something.

hey superpilun..where'd you put your MAF sensor? Well I forget what your your car is so I don't even know if you have one. I keep debating wheter or not to put mine in the air inlet tube or not. Right now it's in the charge pipe.

yeah, I couldn't remember what year he had

98-99 pride!