very true....they never flow anywhere near the same as the stock ford PCV's. In an aftermarket application such as this, that may not matter, but on stock motors, it creates real headaches because it throws the fuel trim all out of wack.

 

I haven't heard of any super coupe guys having PCV problems
(my uncle runs one, and hangs with those guys)

Maybe the PCV will allow some air backwards under VERY high boost?? (not 2 psi though)

I have one and put 20 psi from the rubber tipped blow gun from my air compressor to it on the hose barb side , and it works great as a check valve. There is a little air leakage (not 100% perfect) but nothing that would make me believe it will cause any problems at all.

I think if you get boost blowing from the intake past the PCV valve you need a better quality PCV valve.

 

I run a Supercoupe PCV with an Incon one way valve before it. On the valve cover side I have a 5/8" line going to a catch can then going to the turbo inlet after the air meter so it will scavenge under boost. It seems to work great, with the stock 3/8" line there it would kick the oil out of the dipstick, and now it doesnt.

 

:withstu:

 

so what do you guys do that have blow through MAF's???

 

I fought this problem on my S-Trimmed 95 for quite a while. I'd blow the dipstick out after a full throttle pass, time after time. After much trial and error I finally found something that worked for me...I'll try to essplain eet best as possible.. (dashes denote vacuum hose). 1 way ck valve is a brake booster valve off a Toyota.

Turbo Coupe PCV--------*1 way ck valve*-----------Vacuum source on intake manifold.


Driver side V/C nipple------------------clear plastic fuel filter from Pep Boys---------------------Nipple drilled into S/C Power Pipe between MAF and SC inlet.

My theory was that under boost the vacuum on the inlet side of the SC would help draw vapor out of the engine. The filter would stop any raw oil from entering the SC (which it did remarkably well). The ck valve in the pcv hose would be a safeguard to help stop 14#'s of boost from blowing the pcv back open (which it did very well also). Now was I getting a unmetered leak from the evac side???? Maybe...Was it any worse than having an open breather??? Doubt it......did it fix my dipstick launching routine??? Yes....Were there any side effects as a result of this fix?? None that I discovered. Someone may have touched on this way earlier in the post, but I probably skimmed over it. If I'm waaay off base on this, please fill me in cuz it seemed to work for me and a few others I showed it too. Maybe there was a problem we were overlooking. Thanks.


*edit* rl- actually said the same thing, just in alot less words

 

:withstu: that's how i ran mine and i put a one way check valve before the vacuum tree

 

I used to run a breather off my vc but it would drip oil onto my wires and cause fires...not good. So instead I ran the regular oil cap with a line to a catch can with a breather. I also run another line from my PCV valve on the back of my intake to the other line on my catch can. So far so good. I do notice that when I turn the engine off I hear whistle sound, like pressure being released, not sure what it is. When I first set it up I only ran a line from my vc and plugged the PCV opening. I haven't noticed any difference from running it plugged to running the PCV valve with a line to my catch can. The one thing I can confirm though is, that running a line from the PCV valve to the catch can, I get a lot more oil filling the catch can than I did without it. Performance wise, I can't tell any difference.

Here is a pic of my setup. You can see the line running from my passenger side vc to the catch can below my battery. The other line runs to the back of my intake, you can't see it in this picture.



The catch can I use.

 

i wasnt going to add to this post as i am still struggling to completely understand the pcv system myself, but i just went through a lot of this this past weekend with my lil 2.3L turbo turd and i finally choose an all metal PCV valve from a 94 twin turbo 300zx as it seals up a lot better than the turbocoupe or supercoupe (around me, the orginal spec pcvs for the turbo fords are almost impossible to get for some reason) pcvs under boost conditions.. plus the intake side of it is threaded, it it can be tapped right into a metal inlet line of the upper intake easily or simply clamped into a 5/8" line..

 

Thanks for passing that along......did you do tests to see which is better, or is it obviously better by looking at it??

 

what about using a filter on the VC and running the stock pvc line to the turbo inlet (between air filter and turbo)? will this be enough suction power? At least this way no unmetered air gets in.

 

yea i brought it back from the dead.... anyway, can you just run check valves in the vc-tb line and pcv-intake line, leave them in stock locations and everything, just so air can flow from the crankcase to the intake but not into the crankcase? this ensures less (or equal)pressure in crankcase at all times, does not affect metering, and eliminates the need for catch cans. am i retarded

 

I don't think it is a good idea to have vauum on the crankcase with the PCV and not being able to let air into the crankcase.

Why is everybody so afraid of unmetered air?? I run a small breather filter on my filler neck, and the computer obviously doesn't care.

 

subscribing

 

i thought the crankcase was supposed to be under vacum

 

In a race application, definitely.... but the lips on the crank seals you have in now are facing the wrong way for a crankcase under full vacuum. The seal lips now face inward. They need to be turned around for crankcase vacuum.

Although rare, when under vacuum you could suck dirt and rainwater past your seals as they are now. I also know that folks mention hearing a whistling sound after shutdown as negative pressure in the crankcase stabilizes.

Also, let say you have just the PCV valve and the breather line, both with check valves. While under 15 lbs boost you suddenly blow a hole in the piston.(or just have a worn out engine, probably more common) Pressure can't go into the intake cause theres boost there. Can't go out the PCV cause theres boost there, too. It will probably blow the dipstick out and make a big mess.


I added the little breather to my filler tube nipple years ago to see if it would fix a weird idle problem after swapping in a "B" cam. It did, so I left it.

So, I am letting unmetered air into the crankcase, and it gets sucked into the intake through the PCV. BIG fu*King deal, the engine and computer obviuosly don't care. It has been this way for three years and 40,000 miles now. I know it is supposed to be some unspeakable sin to let unmetered air into the system..........everybody who says it is such a terrible and bad thing can go get bent.

 

there is vacum in the crankcase on the stock mustang. thats what the pcv does.
plus blowby would just in effect keep the crankcase pressure just under or equal to manifold pressure, instead or at high vacum

 

No, not really any at all.

The air hose from the oil filler tube to the throttle body (BEFORE the throttle plate) lets air into the crankcase so vacuum never builds up.

 

Not at all. You must have never had a vehicle that blew the dipstick out
(there are two types of people. Those who have and those who will)

 

:getit: patiently waiting :getit: