I just installed a recirc. Forbe BOV. I put the green spring in 1st, it fluttered when I lifted after building boost, I changed to yellow and blue and it still fluttered.
Is it suposed to make a fluttering noise?
I have it installed the same orientation as the stock BOV.
What the hell is going on?

It does seem to pull harder with all 3 springs. I'm thinking of just putting the green back in and dealing with the flutter noise.
Any help ?

 

hrmm mine stopped fluttering when i put the green spring.... it actually whistles some times

 

I have a Forge recirculating valve and it flutters when I let off the gas. I am using the blue spring.
It should not flutter when you are accelerating.

 

change the orientation so it looks like this. It might help, it helped me atleast. I hope the attached picture helps you with what I am talking about.

 

High rpm or light throttle? Mine does it at light throttle/ settling into a cruize sometimes... Which I'd expect slowly transitioning from boost to vaccum.

 

I have tried all the springs except the red. It is way to thick. I have the green in now. It is the weakest. The weakest should stop all the fluttering. It flutteres because the valve closes back then reopens. The weakest has the best chance of opening and staying open, and letting out the air. The stronger spring closes back the quickest, and takes more boost psi to open. I have stopped most of the fluttering with this approach. It still flutters some maybe two times under hard boost with a quick let off. The stuttering and shuddering has stopped all together because the air let out of the DV is greater in the first valve release, but still once or twice of the woosh. I have not tried the different posision of the valve, from what I understand it is just fine to put in that direction because of the way it is made. I hope this helps.

 

I have mine just like MANGOOK, no flutter.

 

Hey guys,

Besides the spring and the orientation, make sure your vac line isn't crimped.

I had light fluttering/stumbling in 5th gear sometimes at 5th, then I noticed that the vac line from the BOV was crimped where I had it Teed to my MBC. I cut it so it was a smoother transition and the stumbling went away.

Doesn't the spring hold it shut and the vac line open or close the valve? I thought that it opened when it hit a certain amt of vacuum.

Thoughts?

FB

 

just an fyi. with my boost controller set at 19-20 psi when i put in the green spring my boost was erratic at high rpms......in other words it would leak. put the blue back in and i get rock solid boost all day long. just something to consider.

 

hrmm
i have 21 lbs with green and i don't leak

 

Depending on the design of the valve, the Vacuum line could be assisting in keeping the DV closed (Boost pressure helps to hold the actuator closed) If you disconnect the stock DV's vacuum source, it "flutters" and it will also not maintain boost above 12psi or so..

 

First thing is to verify the vacuum line is not crimped in any way. Second thing is it seems the US spec cars work very well with the yellow spring in them. Our car would bleed boost pressure with the green spring at WOT. The diverter valve is a single piston which is acted on by positive and negative pressure on both sides of the piston. At part throttle, or heavy throttle, with low to medium boost pressures you will have some flutter as the transition of the pressures is different than at WOT and full boost. If there is flutter at WOT and full boost, the spring is too stiff and you need to step down to the next softest. We play around more with the VTA BOV on our car in which it is very noticeable both in sound and power when the spring is too soft and releases pressure early. Our VTA is a twin piston valve which means that the main piston is acting on both positive and negative pressure while the secondary piston only acts on positive pressure. Most of you run an open element air filter which allows the venting of the diverter valve to be heard much easier and you should be able to hear if the valve vents early while your foot is planted on the floorboard. Remember the valve is designed to help protect the turbo in high boost applications, not part throttle at 10psi for example. The lower boost pressure in this example is not able to "push" on the bottom of the valve like 20psi would. This pushing action along with the transition into vacuum, or "Pulling" on the top of the valve will move the piston. At lower pressures it is very difficult for the valve to fully open with the lack of pressure acting against the spring tension which usually equates to "flutter". The valve should not flutter in WOT and high boost applications. If it does, call us or email us and we will see what may be going on in your system.

 

Why would anyone install this crap anyway? To look cool? Has anyone done a before and after dyno? This does NOTHING for the evo, but I guess you do get the bling bling factor of have the pssst sound. lol

 

Hi,

I believe most/all of this thread is referencing the recirculating DV from Forge, which doesn't really make a lot of noise... The stock valve may leak boost, esp if you raise boost or even hold it into the higher rpm ranges.

As for dyno proof, there was a thread or two indicating slight gains in back to back runs IIRC (3-4 HP?). For me, it was more an issue to ensure that I am getting max efficiency. The stock piece is pretty lame, although not as lame as the stock DV in my Audi A4 1.8T. The forge is very nicely made, is adustable, and rebuildable.

Take care,

FB

 

My oe valve leaks under full stock boost... it really is ****ty. I bought the Forge Diverter valve in black because I loath Bling Bling. It is almost as quiet as stock...