m2cupcar

iTrader: (5)

show me- I was using what I thought was a first gen supra turbo pcv valve (non OE). Had a metal valve core, but after 1k miles was already leaking.

PAT!

iTrader: (1)

I'm refering to a turbo bypass valve. We make a replacement, the OEM piece should look like this but in plastic:
http://www.forgemotorsport.com/conte...duct=FMDVMSP02

Manifold pressure will open or close the valve when its needed. Under boost it will be shut, open under vacuum. You can get them online or at junkyards for a song. That and a few reducers should do the trick...

I plan on trying one of our fancy alloy jobbers once I get the turbo in my car...

rb26dett

LOL

Agreed, for extreme use (of whichever type) it is far too small in there. Hence open it out, add another on the other bank, and do what you wish with them, BUT, leave the pcv system in place and in good condition.

Fred.

rb26dett

You don't think the idle might be a wee bit high with a 19mm hole to breath through and bypass the throttle do you? How else would you use it?

Braineack

iTrader: (62)

wouldn't the simplest solution be a one way check valve inline with the pcv. that way the pcv can still work as intended, and the check valve would be extra insurance that the crankcase will never get boost.

rb26dett

But but but, that's exactly what a pcv IS :-) I good nice softly sprung good sealing check valve would be excellent, you could always bring the flow down if you wanted to by using some sort of restrictor inline with it.

AbeFM

iTrader: (3)

I couldn't find a good check valve, but I did put two in there, hoping the pressure drop across the first would be enough to leave one left. Probably crap, but it's what I did.

That makes total sense. People who take short trips like me get water in their oil, when you drive for a long time, the water should boil out. Ok, it would be awesome to seperate it, but you can probably change your oil less often if you don't dump it back in.

I think you can dump it back in by hand if it's clean. After the water comes out.


Isn't boost-dust something you can pour in the tank? I'm kinda wondering about the lack of suction....

What does something like that cost? If the megasquirt had more channels, you could make it electronic. :-)

Anyway, having a suction would help - with a decent catch can, you could plumb it back into the intake, ahead of the turbo, and that can't hurt. But perhaps a bigger bung would help.

There's not as much use to sucking off when not on boost..... And on boost, all these check-valves are closed. If it switched to atmospheric would work....

rb26dett

Probably not a bad idea at all!

You have to lift to get suction :-) nurburgring = extended periods at WOT and 120+ mph

Not true :-p (least, that's not what that red head of yours told me the other night ;-) )

Fred.

PAT!

iTrader: (1)

I used to get them free from Supra owners after they installed an upgraded valve. Maybe 5-10 from a junkyard.

The valve should pretty much exactly mimic the operation of a check-valve but without the leaking and blowing open.

I'm proposing installing it off of the valve cover, flow should be restricted by the size of that orifice.

Sorry I didn't quote, I'm feeling lazy...

rb26dett

If it were a steady state flow it would mimic it exactly, but being a pulsed flow it will not. It will puff out and then back in again. With the check valve it works like a small pump removing gas with each pulse.

Think about a piece of elastic with a ratchet on it.

AbeFM

iTrader: (3)

So... Why not hook it in backwards.

You have a check valve to the intake manifold, so when in vacuum, you get suction into the motor. When on boost, there's no flow (unless your crankcase pressure is higher than boost pressure). No catch can here

Also, have a boost actuated valve, when the engine boosts, it would open, the rest of the time it's closed. This would have a catch can, and vent to atmosphere (or maybe between air filter and turbo). The giant opening wouldn't matter since it would only be open on boost, and doesn't go to the manifold so it won't effect idle.

So there's no vacuum leak to worry about, you're covered under boost and vacuum, you're not leaking all over the place, and your crankcase is well vented.

rb26dett

The big thing with the FE3 at least is just totally insufficient area to exit when the pcv is shut at WOT or on boost. The hole is just too small. Enlarging it and adding a second is a good way to go IMO.

Fra66L

I have a similar setup, but I used an electronics jiffy box w/rubber seal, stuffed it full of stainless steel wool, and put a screen in so no strands would get sucked into the motor. It seems to be trapping a very small amount of oil post PCV...

AbeFM

iTrader: (3)

I just got a box, a nice one, and I'm stoked!

I want to get a much bigger outlet. Then I guess I'll go from that, to the can, to a T which goes to a vent or the intake manifold, with appropriate check valves.

And I should stuff the box with steel wool and screens.

^tyrant^

m2cupcar, where abouts GA are you?

curly

iTrader: (25)

alright, so I have the stock pcv valve in, and a little filter on the driver side of the valve cover. am I using barrowed time with this setup, much like my 6" diff? I know the filter is supposed to give a sketchy idle once in a while, but I only idle when there's a spec miata infront of me on the track

mostly I road race my car, although it still sees a couple thousand (2 or 3k) street miles a year. whats the best option for this pcv issue? 323 valve? catch can? from how much everyone seems to know about the situation, I think I missed a previous thread...

m2cupcar

iTrader: (5)

Near Emory U.
Went out and made a couple of ~15psi runs (sans pcv valve) from low rpm to rev limit using the OE vent and the pcv vent to the catch can. Still got oil seepage from the cam cover gasket. The passage at both ports in the Mazda cam cover is not quite 3/16" (~9mm). So I swapped in my modded Kia valve cover (post documenting cam cover mods here - and here - original thread).

Went back out and made the same runs and had zero visible oil seepage and there was no noticeable increase in the can oil level. Yes, the cam cover gaskets weren't the same- but the Kia gasket is about 3 years old and the other a year. Both feel similar. At ~9psi (waste gate actuator base) there's no problems - but the higher boost changes all that.

rb26dett

Great test rob, and exactly as I thought it would be. Now, leave the kia top on, put the ordinary pcv back in and call it a day :-p

Fred.

m2cupcar

iTrader: (5)

I need to buy a proper mazda turbo pcv. I had a third party supra unit on and it couldn't take over the base WG boost. Same with all the other OE units I have laying around... Though I haven't tried them with the new cam cover... maybe that was your point.

rb26dett

No, I was just giving you **** :-)

Fresh OEM FTW :-)

I look forward to you having it all working properly.

HMMMMMMMMMMMM, I wonder if my leaking rear main seal is because of this?? Perhaps I didn't stuff up the install, perhaps my 17psi pushed it out!??

Fred.