3rd Gen Jeremy

I've got a Greddy Type RS BOV. I've recently noticed that it's open at idle. That means that when I'm cruising and I've got a vacuum, the BOV is open and sucking in unfiltered air. I'm assuming a new spring work but I'd like to hear what you guys think. Where could I find one if it would?

Has anyone else run into this problem? If so, what did you do to fix it.

I've searched and I'm not getting any good answers. Even the stock BOV does this if it's vented without a filter.

rx slim

I can't help you, but I always wondered why my stock BOV had a filter on it. . .now I know!

PDViper77

iTrader: (9)

The greddy type RS is junk. I had one and it leaked too. Get rid of that piece of garbage. Either get a Tail or an HKS, they are way better in quality than greddy.

Herblenny

iTrader: (13)

First of all, BOV will never such in air.. And second, its the vacuum that opens BOV.. Learn about how it works and it will make sense..

3rd Gen Jeremy

Actualy that's not true. I'm well aware how a BOV works. As you apply a vacuum to the line, the valve will open. In the case of the GReddy Type RS, it's -13 inHg.

Our cars idle at anywhere between -15 and -18 inHg. Therefore, at idle, the valve would be open. As we all know, an open valve doesn't block air from entering the system, it's not a check valve. Since the turbos are not providing boost at this point, the engine sucks air back through the valve.

With a stock setup, the valve opens at -4 inHg (approximately), but it is plumbed to the airbox to prevent this condition. When you remove the airbox and don't filter the BOV discharge, the condition I'm describing happens.

I believe that I have just proved that I know how it works. Thanks for trying to help.

JDawG707

have u tried to tightin the spring? and if it leaks, its because ur running over 19PSI with the spring all the way pushed in LMAO!

3rd Gen Jeremy

It's as tight as it can go. I'm only running 16 psi at peak. I bought it used and it had some rust on the inside. I disassembled the valve and cleaned it really good. Now there's no rust at all on it. However, I'm thinking that the spring might have been weakened in the process or by the rust.

I'm looking for ideas on replacement springs. I can't find anywhere to get just the spring.

The problem I'm really struggling with is that it's open during idle. With the spring tightened all the way down on yours, is the valve open at idle?

Thanks,
Jeremy

DamonB

I've noticed this about many aftermarket BOV.

I've seen a bunch of them that do.

Yep. That's exactly when they start sucking in unfiltered air

3rd Gen Jeremy

I knew somebody would back me up. Thanks.

Herblenny

iTrader: (13)

Sorry about that.. I guess I was wrong.. LOL!

In the theory, I was thinking turbo is still spinning and creating flow of air thru the piping.. Thought it would over pass vacuum created in the manifold since throttle is closed. I guess you guys are saying that at idle turbos are creating less pressure.. If I'm wrong, you thought me something new.. My appology to 3rd Gen Jeremy.

3rd Gen Jeremy

No need for apology. I try to learn something new everyday. Hell that's why I'm always on here. I'm just trying to learn as much as I can. I was hoping somebody had a fix for this BOV but I guess it's just the nature of this type. I guess our cars pull more vacuum at idle than others.

I'm probably going to go with the HKS instead of the GReddy.

DamonB

It comes down to spring pressure. If the spring could somehow be shimmed you could most likely adjust the BOV so it stays shut at idle.

The vacuum in the manifold behind the throttle plates is where the BOV gets it's signal from so it's the manifold vacuum that actuates the BOV regardless of where the BOV is mounted on the intake tract. Whatever the boost gauge is reading is the same signal that the BOV is seeing.

The BOV opens when manifold vac overpowers the spring inside the BOV. If the spring pressure is less than what the manifold vacuum is at idle the BOV will remain open at idle.

3rd Gen Jeremy

That's an idea! I knew somebody would have an idea. I'll try i t out and see if I can make it happen. If I can get the valve to stay shut at -17 inHg then I'll be in business.

Thanks,
Jeremy

Monsterbox

iTrader: (6)

ur valve is likely broken

these type rs are terrible quality when it comes to spring adjustment


my spring adjustment screw threaded itself out when i tightened it from the back pressure of the spring pushing agains the screw out of its own threads...i tapped the hole to 5/16-18 size thread-MUCH BIGGER screw works perfect now

bov DOES not leak at idle or at any rpm unlike the stock bov which constantly releases air between -13hg and 0psi

the greddy rs WILL NOT suck in air at all at any rpm and should not...no bov will let air back through it IS a check valve that it opened by vaccuum....u cannot suck air into the bov unless the vaccuum it causing it to open early (stock BOV)

DamonB

No it is not. The BOV has no idea what the air inside the piping is doing. The BOV only knows "open" and "closed". When it is open and when it is closed is a combination of spring pressure and manifold pressure.

3rd Gen Jeremy

Monsterbox,

Do me a favor. Grab a MightyVac, apply vacuum to the BOV until the valve opens. When it does open, note the reading on the MightyVac and examine the open valve. You'll notice that it's just a plunger and that you can stick you're finger through it. If you can do that, don't you think that air could also go backwards through the valve?

If you're reading on the MightyVac is greater than -18 in Hg, you should be good unless the car is cold. Otherwise, you'll be suffering from the same problem that we're talking about. If it never opens, congratulations, you've sealed it shut permanantly.

I'm sure if you try this, you'll see what we're all talking about.

By the way, you're screw wouldn't back out if you put teflon tape on it, it also seals the chamber for quicker response.

Monsterbox

iTrader: (6)

I do not own a MightyVac, but trust me the valve does NOT let air out at idle and this is with the screw less than halfway in. I have teflon wrapped the screw and the original screw did not back itself out...it pushed the threading out because of the cheap aluminum. Your spring must be cut short or something odd because the valve does not release air unless vaccum is deliberately applied by releasing throttle.



IIRC, when the the original faulty screw was in the valve, it could not tighten it whatsoever and the valve would release air all the time exactly like the stock bov until I hit -5hg I still cannot understand how it could suck in air unless the screw was removed on the top

CantGoStraight

I'm not sure why you would think a pressurized "BOV" would be sucking in air but it can't happen. If someone put in the BOV and hooked it to the CRV line then it would be open till 4500 RPM's You may be confusing manifold vacuum with intake.

CantGoStraight

Your turbo's will push enough air to prevent air from coming back in the BOV even at idle. You also are confusing manifold vacuum with the intake. Most everyone runs these to open atmosphere (for boost venting noise purposes) some (like me put filters on the end to reduce this noise) air will not go in this valve unless the turbo's are running backwards.

revhardallday

iTrader: (1)

hey wuts up just installed greddy bov type s on my fd and i think the valve is not opening wen i let of the gas!! plus i dont know if i hooked it up right.....i removed both stock valves that were on there......but i can here the pssssst sound wen i let of the gas.....but not coming from the bov???????

crazyrx7

I have 2 Greddy RS valves on my car. They are closed at idle. If you don't have the spring tension tight enough then at idle you will have a vacuum leak (because the valve is open). Keep tightening the screw until the valve stays closed. Then your vacuun leak will go away.

R.K.

Herblenny

iTrader: (13)

Well, I did a quick test this afternoon with my FD..

During Idle, I took off the BOV and put a rubber glove on it instead of the BOV... to check to see if it is sucking in air..

Just so you know, my car pulls about 15-16lbs of vacuum during idle.. Rebuilt engine with about 10k on it.

And guess what, it slowly filled the glove with air.. instead of sucking in..

This is the reason why I stated earlier that BOV shouldn't sucking in air during idle... Maybe if you had oversize BOV by the elbow side, maybe.. But not the stock location.

Monsterbox

iTrader: (6)

theres just no possible that the throttle body vaccuums air stronger than the force of the turbos blowing air at idle

TpCpLaYa

iTrader: (10)

i know that if i put my hand over my type-s that is mounted on my elbow i can feel air coming out during idle.

3rd Gen Jeremy

I'll have to try the rubber glove trick. I've got mine on the elbow as well. I'll let you guys know how it shakes out.