Dude, try a lighter spring.... move down 1 in tension. If you are using yellow, then switch to green. However, be sure to keep an eye on boost to ensure that the valve is holding as it should to redline.

 

There is another post I started about the problem with the valve, I think it stems from the large piston assembly in the new valves. I have since gone back to the old piston design. Not everyone else has that option though.
Of course the old valve when install with the piston face to boost pressure makes the screeching noise that can be very annoying so I have it installed backwards, so to speak. The two valves have different piston displacement on the vacuum side so there is a difference in the spring affect between one piston and the other.
While I love the design of the valve in principle, it does have it's issues. My other post is a couple of months old now and Forge told me they would get back to me about the problem.

I am suprised that even after porting it out you had to replace it I thought it was the fix. If I had the extra original piston design I would let you try that one just to see how it worked with your setup. Of course if I had extra pistons lying around I could probably come up with a good solution. The ribbing so to speak on the new valve could probably de removed down to the lands and the valve would still seat properly and the flow would increas substantially. Problem is at this point, I don't have a real efficient way of removing them. I do have a friend that runs a auto machine shop, I will have to ask him if he has a means to remove the ribs cleanly.

If you do go to Forge with that valve, please let us all know how you make out. There are quite a few cars out there with this flutter surge that are running the stock airbox and the just don't know it because they 1) can't hear it 2) don't know any better.

But ultimately like it says in my signature, it's primarly purpose is surge prevention. If it doesn't do that efficiently then you are doing damage in some part to the turbo. This goes bck to a thread I posted that got no response about running two DV valves to increase the cfm flow. It is a trade off between safety and turbine speed to less safe but retention of some presure in IC tubing on shifts. This can go either way and no one answered because I don't think anyone could give a validd response as to what is better. If I had the IC piping to experiment I would try it but an inlet with dump tubes and an upper pipe with two fittings is not exactly easy to come by. I can have it made but still need the raw materials and another DV to try it. Maybe someday.

 

Surging is easily noticed because you feel the car 'shake' or 'flutter' when it's occurring. Now I'm wondering if we're talking bout' the same thing........ when I had the yellow spring installed, my car would flutter (surge) for 1-2 secs when the BOV was bleeding off excess boost. Now (with the green spring).... it is nice and smooth when bleeding off excess boost. However.... I do have an AEM intake now but I could easily feel the surging when I had my previous stock airbox in tact also.

 

I Have the H34 (this is all a lie Mitsubishi to impress the others on this board) and I found that it worked best with three shims. With four when I was taking a high speed sweeping corner say in fourth gear a let off of the throttle would result in a good lurch as the valve sat for a split second before releasing pressure. When you are right at the limits of adhesion this jerk sometime would lead to some oversteer. I do realise the effect of weight transfer with the release of throttle, but this was a good jerk that would cause a large transfer of the weight to the front. With three shims it opens sooner and smoother so as to reduce the jerk and make lifting in mid corner more progressive and easy so as to tighten the driving line in a more controled manner. Just some experience that I wanted to pass on. It still seems to hold boost well with no apparent leaking.

 

Did you buy the EVO 8 flange with it

 

You don't feel it when the clutch is in for shifting, that is more what I am talking about. I am runnign nlue with old piston design and it's pretty good, though I think Iwant to lighten it a little.

 

With forge out of the way, its either gonna be GFB stealth or TXS H34..... anyone have any experiences with the stealth??

 

Graysilvia, did you have to use an adaptor kit with the TXS H34? Thanks.

 

The 3000GT adapter kit will work if they don't have one for the Evo yet.

 

I have to say I'm happy with my forge valve. I did have part throttle surge with the blue spring running stock boost and stock airbox/filter. Blue was fine at wide open throttle and did not flutter when dumping full boost. It would surge when going from throttle on to throttle off at partial boost. I dropped in the yellow spring and it has been fine since. For that matter, my stock valve would cause surge If I stepped out of the gas to quickly at part throttle.

 

No sir, the one I bought came with the little flange that goes onto the inlet side of the BOV, I don't know if they all come with that piece or if you have to buy seperately. But, other than that it goes right in to the stock recirc tubing.

 

Brandon, did it look something like this? Thanks a bunch.

 

I have actually tested this turbo xs valve, unfortunately I really would not recommend it. There is no rubber seal for the valve or the actuator and they both leak. It also does not have a very good actuator to valve size ratio. You can adjust it for good drivability, but it leaks and will not hold up as well at higher boost compared to the Forge or Greddy.
I don't see how you guy's are having problems with the Forge valve. IMO the only possible minor issue was maybe the valve opening could be a little bigger (although it is about the same size as the stock DV).
I recently bench and road tested a fellow EVO owners Forge DV with a blue spring. Based on my bench testing it should work really well, during my test drive it seemed fine.
Even with the blue spring it should surge less than the stock valve, you could easily go with a softer spring but I don't know if you need too.
Are you guy's just worried about sound? Hell as long as the drivability is good do not worry about the noises (unless they annoy you). Just because you hear the valve openning and closing under part throttle does not mean it's surging, it's probably actually preventing it. If you were really getting surge you will know it because the car drivability goes to hell on part throttle.

 

What's up Silver Surfer!

Always good to hear from u man......

Hey man, check this out. Like I stated earlier, I had to back off to the green (least amount of tension) spring because my car would "buck" or shake when the valve was bleeing off excess boost at part throttle.... or just when I would let off the throttle completely. The yellow spring was doing well (as far as holding boost), but part and no throttle surging became aggrivating as hell. Upon advice from my boy Robert over at RRE... I moved down a spring to green... and the part throttle surging discontinued immeditaly. Still, for the power that I'm making, and the fact that I'm running 20 psi to 18 at redline, wouldn't you think that I should be able to run a stiffer spring like the yellow or maybe blue. I did just install my AEM intake...... so maybe I should try a stiffer spring now.

Yo take a look at my sig below to see what I'm running.... and c if u can offer some advice as to what may have been happening. Once again... I believe it could be identified as surging -- at light/part throttle.... or when I'd let off the throttle completely in 3rd, 4th, or 5th gear.... my car would flutter (shake) 2-4 times or so... and it ALWAYS occured when the valve was bleeing off excess boost. Now.... with the green spring.... that "flutter" has been replaced by the valve bleeding off boost nice and smoothly as it should. However, I'm a little worried that the valve isn't holding boost as well since I'm running such a "loose" spring (green).

 

That's it exactly.