Following some other long and heated discussions in threads concerning the part throttle fluttering often experienced when installing our Standard Evo Recirc. Valve, part number FMEVO15, we have spent some time working on a solution to the problem.

The following is a possible solution that we have had some success with over the last few weeks.

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We have found that by installing the valve in reverse orientation, we have almost completely eliminated the part throttle fluttering concerns.

There are two basic ways to install a recirculating valve:

Normal/OEM Installation:


Reversed Installation:


I will try to take other pictures of each orientation installed on a vehicle later.

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By reversing the orientation of the valve (ie: allowing the pressure to enter the side port instead of the bottom port), there seems to be improved airflow through the body of the valve, which was a major cause of the fluttering concern.

We are still working on another possible solution to this occurrance, but will not have any more information about it for a couple of weeks.

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So, for all future installations of this valve onto an Evo, 2G Eclipse, or GTO/3000GT, please reverse the valve's orientation from stock to prevent the part throttle fluttering concern.

I will continue to post updates to this post and in this thread as we have new information and with answers to any specific questions concerning this solution.

 

I had my forge valve on backwards also but one thing i noticed is that the throttle became quite rough. ex. When lifting off the gas the car would buck harder. I did notice that the fluttering was nearly gone.

 

We've been playing with it for a couple weeks now and haven't noticed that concern.

We have found there to be almost stock driveability.

We are aware that the piston design is not ideal to promote the highest amount of airflow, but that is something else we are currently working on.

 

Same experience. And I don't like the idea of installing something the way engineers did not meant it to be installed, imho. I have the softest possible spring on the bov and it holds boost fine, BUT even with that spring... the flutter is still VERY noticeable. A used recir greddy type-s looks very enticing right now.

 

Wow....install it backwards... are you serious?

 

Mike,
Just to clarify, before installing the valve backwards should a soft spring be installed in the valve? I'd imagine that with a stiffer spring the valve would be unable to open as it is being opened by engine vacuum alone.

-Paul

 

I had the same style Forge valve on my GTI 1.8T and had it installed backwards and it worked better.

 

There is no reason for the valve not to be able to function properly when installed in reverse orientation.

The design of the piston allows for the positive pressure to open the piston in the same way as if it were installed normally. The grooves around the body of the piston allow for the pressure to force the piston up in the same manner as if the pressure were pushing on the bottom of the piston. It is less linear, but should operate perfectly fine.

The OEM valves CANNOT be installed in this way due to the three-chambered design, but ours can.

I'm not in a position to post this solution in front of thousands of people if it wouldn't work.

 

I've been doing this for 2 years. If you look back at some of the past posts regarding the fluttering, you'll notice that myself and many others have advocated reversing the orientation of the Forge BOV.

 

I'm not promoting this as a new discovery. Reversing the valves is a common occurrance in other markets (VW, Audi) and it is sometimes effective at prolonging the life of diaphragm valves and providing more linear operation in other valves.

We have never personally tried this ourselves on our own Evo's, but since doing so, we have found it to help eliminate this problem.

I am still working on another more permanent solution to the problem, but this should provide some relief to those who are experiencing some issues until I figure out some more things.

 

I have mine and have installed one on another Evo valve way it came and it works great. I have had no problems at all with my forge valve.

 

I switched the orientation of my forge bov last night, and what a difference it made. No more fluttering on low boost anymore. I had problems with that damn bucking when I would slightly roll on and off throttle at low boost (<.75bar), but now it is gone.

Thanks for the fix!!

 

Nice to hear. That's the problem I'm currently having with the turbo xs rfl recirculating. WOT it's okay but at low boost it will flutter and act like the bov is opening and closing. Just ordered the forge RS bov so hope this baby will hold boost and won't flutter

 

I'm using this exact diverter valve and I love it. It is WAY better than the Greddy Type s and the Go Fast Bits. I know because I have had all three. The Forge has the closest-to-stock drivability while still holding gobs of boost.

 

me being one of them who installed the valve in the reverse position. i actually noticed that the car would flutter more in this position and was actually louder. i switched it to the stock position and noticed that the car was smother and the valve was quiter. i was in a huge debate in a thread over this and i was told that the reverse was wrong in everyway by retards, me knowing how the valve works, know that it would work either position. so i did change it to the stock position just to see if anything would happen, and nothing really happen. so in conclusion, u can run this valve either way u want to, it will work and hold boost in both positions. its more of what u prefer.