Anyone know where to get an air check valve? Need for my BOV project

[JoeyGST]

I need to find an air check valve that will only let air
go through one way, and vent it into the atmosphere.

I couldn't find one like that, only a swing check valve for
water hoses at the local Home Depot.

Anyway, I need it so I can try venting my blow-off valve
to the air without getting idle problems.

Post up any suggestions on good hardware places in the
Bay area to try ?

-JoeyGST

[TheCamel]

Ok one problem when venting the BOV to the atmosphere. Your car will have a tednadancy to stall. The reason is that the BOV releases air measured already to the atmosphere, but the fuel is already measured by the computer for that air that never shows up, which immediately leads to an overrich condition. There is a setting on a Super AFC in order to handle this problem. Most manufactuers have internal BOV's in order to put that air back into the intake right before the turbo for this reason.

This quote was not only for DSM's but for all turbocharged cars unless you are running a Manifold Absolute Pressure sensor (MAP) The the stalling problems are due to a rich mixture in the combustion chamber because the injectors have a different duty cycle to bring the engine revs down when the throttle plates close. This is factory progrrammed into the ECU to compensate for a momentary lapse of boost and allows it to return to idle smothly. By redirecting the air out of the intake stream is like puring raw gasoline down a carborator on an engine that is running at idle, it was unmeasured fuel and not enough air to compensate. Your check valve is the same thing as your blow off valve in the first place.

TC

[JoeyGST]

TheCamel: I understand all that already. I have a different
design, placing the check valve AFTER the blow-off valve,
so that at idle, the air is not leaking quite as bad. It'd
be tapped in the dump tube that goes back into the intake,
so the whole system is still connected, but the valve will
open and vent air dumped by BOV under boost.

It's really hard to explain, but someone else already did
it to their car and claims it is running much better, and
so I intend to try the same ;)

I just need to find the same kind of design check valve
as he used, which is very hard in my area for some reason.

-JoeyGST

[Mystik]

what type of BOV do you use joey?

[JoeyGST]

Greddy Type-S
I'm getting annoyed of the high pitched squeak it makes
I want my 1G BOV's deep aggressive air-dump sound back :(

-JoeyGST

[Mystik]

well, if you want to use your 1g again just read my post about crushing the BOV.. i did it and my car runs great, even with no fuel managment.. had it like this for a few months now

[JoeyGST]

Yah, cept I sold my 1G BOV :(
How does it sound when crushed? Is it still as loud, or
did it muffle? Does it make the turkey-gobble sound now?
Or is it still the good old "phsst" air-dump sound?

-JoeyGST

[Mystik]

well.. when the bov is facing the stock direction its kinda quiet, but a nice pshhht sound.. same as non crushed. Now, when you flip it around so its facing the fender (which takes a longer hose or some creative routing), under light boost its a little "psst" but when you do a nice full boost blast its a full fledged "PSSSSHHHHHHTTTTTTT", just a massive dump, it sounds great. I just did it to a friends car last night, he also ran into no ideling/stalling problems... and hey, sell that GReedy BOV and buy a 1g, its only $75 :)

[JoeyGST]

Well, because of my upper IC pipe design, I can only make
the BOV face forwards to backwards towards the firewall.
I can't make it face the fender :(

You say you used some longer tubing, what kinda tubing did
you get to replace the stock dump tube? I couldn't find
any tubing that would stay straight and not bend (thus
sealing itself off) to replace the stock dump tube with.

P.S., I sold my 1G BOV for only $40!! And it was in perfect
cond, it just leaked when I ran 20+ psi. Oh well :(

-JoeyGST

[Mystik]

ah, the tubing i was talking about was the vaccum tubing.. but i didnt get new stuff, i took a creative routing method.. lol.. maybe i will take some pics soon and get them on the web

[court]

fish store

[joeelutz]

I have a MR2 turbo with the mass air sensor and a Greddy BOV vented to the outside. The way to get it to function properly at idle, is to adjust the spring tension using the screw on top until there is just enough tension to hold the valve completely closed at idle. It will still function fine to vent the boost between shifts and when you lift up off the gass. It will then go back to closed position due to the spring pressure when the engine idles down.