Agreed, I'm interested but it does look pretty huge. Thats not necessarily a bad thing, just means you have to find a place to shoehorn it in.

One piece of input I'd like to add... I experience the bucking as well and with my EBC off (AEM TruBoost) its the same as putting a line straight to the WGA. When it is on it will not send pressure to the WGA until it sees a set "Spring Crack Pressure" which I currently have set to 15.5psi. Off it seems I get the bucking alot less and that it is also alot less pronounced, but I'm definitely a fan of keeping all air out of the WGA line until its needed there. Another thing I've noticed is that I think that once the car starts bucking I have to back my foot all the way off the gas, otherwise my body is rocking against the car and starting a chain reaction that makes the bucking much worse.

I asked in a local forum that synapse joined and the one thing I still don't get is how you can be sure the valve is 100% closed by the time you are at neutral boost (or exactly the moment that you are at the threshold of boost). If the valve is open at vac, I would think you would want to have it closed by -1 to -.1 in/hg just to ensure that the second you are making boost none is being leaked back into the intake. I realize there are only minute fractions of a second in the difference between pressure of where the valve is and where your throttle body source is, but with and EBC that is pulsing in nature I could see the system getting slightly inefficient at boost ramp up and then every time the boost controller opens for a fraction of a second. It may not be much, but every little bit counts.

 

Block off your exiting port and weld on the flange They offer the weld flange in both SS and AL for both types of charge piping. Rerouting to the intake is easy enough after the welding is done..

 

You get it mounted and test it out yet?

 

The off season moves a lot slower up here in the snowbelt, Mr. Florida.

Aiming for this week. BoxerSix said he's going to weld up the pipe & flange Tuesday, and I'm going to drop off the car Wednesday for installation. We'll test it out and report back results as soon as we can.

 

This is somewhat adjustable with the pre-load setting in the back. But generally speaking the BOV is already closed at about 3" of vacuum

If you have an existing BOV in place that we have a flange for, or even the stock BOV, then there's no need for cut & weld.

 

Oh yeah I forgot that its winter everywhere else.

 

Attention, Bonestock! The Evo was dropped off tonight to have the Synchronic valve installed (and a few other things addressed).

 

You da man!!!!!! My FQ340 BPV is fluttering so bad lately I am considering removing it all together and doing without. Lemme know how you get on. I have cash ready to buy one if it solves our problem. Heck feel free to PM me your number and I'll give you a call to discuss your findings.

 

Well for the folks tuning into this issue I'm posting to say that it has not been solved yet, however I haven't resorted to all line connection scenarios as of yet. I'm going to keep Erics car overnight and tackle some more ways of plugging this valve in in an attempt to fix this problem. I've tried the following plumbing scenarios and the low rpm, throttle modulation bucking still occurs. It [B]IS[B] better than any other valve to date, but still a problem.

Boost only port C, vac signal at port A + B
Boost only port C, vac signal port A, port B open atmospheric
Boost only port C, vac signal port B, port A open atmospheric

I also TIG welded the intake tube to have the valve recir dump flange closer to the turbocharger side of the intake and away from the MAS to reduce any possibility of a backfeed flow into the signal wire. The valve itself functions flawlessly and I must say as far as pull type valves go it is damn fast reacting and is quite a nice piece of engineered hardware. I wouldn't at all mind putting one or two of these on my up coming Porsche kit car that's for damn sure so if you're just looking for a newer/better valve get this piece for sure.

I ran out of time today to try some more stuff. I want to pull the boost only source and try that, mess with just vac at only A or B without a boost only source, and try pulling the preload spring out of the smaller chamber and try it the other settings all over again.

Without a doubt this is the most son of a mother f'ing frustrating issue I've ever dealt with on a car. Point blank it's damn dangerous on a racetrack at high speed and MUST be eliminated. If this crap happened in a corner at speed you'd surely loose traction and spin out with possibly catastrophic endings

Please note this post is NOT negative towards the Synapse Engineering valve in anyway whatsoever. The valve does what it's supposed to do and is a very nice unit. Under normal and WOT driving conditions this valve is fantastic, doesn't flutter, vents quick, and reacts very quickly. This issue is what I'm pissed at......

Synapse....I may be calling you tomorrow(Friday 11th) just to go over a few things with you. All depends on what happens with the rest of the situations. Also if you can tell me which port(A or B) is the one that goes to the small center chamber that's be great. After the first tests with no luck, I took the valve spring cap off to see how this valve ticked and figured it out, but now can't remember which port went to that center chamber(with the tiny preload spring). Not a big deal, just if you tell me it saves me the hassle of pulling the valve out to take it apart again and look myself. I have something I want to try tomorrow based off that small chamber.......

 

Hmmmm so far it seems like a nice bit of kit... I hope you/synapse can figure out the magical hook up to solve the flutter. if not I dont know what I am going to do. maybe one of those electronically controlled BPV's I have heard of but never researched?????? Thanks for the update so far. I'll be checking often.

 

could have sworn I posted again here about this but here goes anyway.

There's a product already on the market called the DTT or Delta Throttle Timer. This was something I was planning on building myself, but looks to already be on the market(with a patent) You can buy them for about $60 at the link below from Austrailia and costs about $85 shipped to get it here in the states.

http://www.autospeed.com/cgi-bin/bro...dd=1001300009&

The device monitors the TPS voltage and when it detects a rapid decrease in it(lifting off throttle) is sends a signal to control/activate a relay or solenoic. You can even control a large solenoid to completely replace your bypass valve alltogether.

You can also allow it to control a signal solenoid to isolate a standard vac/boost BOv on a motor. Here's how

-Run a vacuum signal line from your intake manifold to a T vacuum fitting. From one end of the T run a vacuum line to a small check valve, flow direction towards the BOV. The other end leave free for the moment.
-After the check valve, install another T vacuum fitting. One end of that T runs to the nipple on the BOV for vacuum/boost signal. The other end goes to a NC(normally closed) vacuum/boost solenoid. BCS, standard solenoid, doesn't matter as long as it can hold a good seal.
-Now run another line from the open end of the solenoid to the open end of the first vacuum T fitting
-Adjust BOV preload as normal
-Hookup DTT to TPS as instructed and run the contol wires to operate the solenoid you installed.

So how does this all work? Simple. Under normal throttle/WOT input the valve acts as normal. The signal line sends a boost reference through the check valve and into the BOV chamber(s). Now the cool thing is the valve is now isolated from all that small throttle modulationg **** us race guys do on the track as the vaccum signal CANNOT reach the BOV chamber due to the one way check valve. Now when you completely lift off the throttle, say to shift or come to a stop, the DTT detects this and sends a signla to the BCS/solenoid to open up....which allows the BOV to get a vacuum reference, "note" the plenum differential, and thus operate and open as usual.

The DTT is fully adjustable in both sensitivity and delay(how long it keep the BCS open for.



I'm (was) working on a back yard version of this for quite some time now, but seems I'm beaten to the punch on it.

 

New post and not a good one.......................

None of the connection scenarios worked to solve this issue. Even Following Synapse's recommendation to pull the pre-load spring and connect as said did nothing. I went ahead and tried something even more bizzar as a last ditch effort and split the boost only signal into two lines, Port C and the central small chamber port(Port A i think) got a boost only signal off the compressor housing. The other open port(B I think) got a vac reference from post throttle off the manifold.

Scenario was to depict that under boost all chamber had boost pressure(as they normally would) but when the throttle was lifted ports A and C would have boost from the compressor housing and port B(the larger of the two upper chambers) would have a vacuum pull. The idea was to have the smaller chamber with boost pressure dampen the valve a bit. Port C with boost pressure would be trying to push the valve open, vacuum at port B would be trying to pull the valve open, and boost at port A would be trying to push the valve CLOSED. The end result was a valve that reacted less to the changes in the intake manifold, however nowhere near enough to eliminate the issue. IT also cause some bit of surge(as I suspected it might) as the valve didn't react nearly as fast as it normally does with vac(or at at both A+B ports.

Even just putting vac to the single small chamber with no boost at C and no vac at Port B didn't solve the issue, just made the valve sluggish.

I'm going ahead with my initial plan and building an isolator circuit for Erics car. Parts should be here within the week.

-Adam

 

*sigh* I had such high hopes. I really appreciate the time you took to post your results. I am gonna look into the DTT. Are you going to run that in conjunction with the Sychronic?

 

Here's a vid of the BOV on streetfire (on an evo). Not sure if it's been posted in this thread yet! Something I just ran across...

http://videos.streetfire.net/video/f...1d0080a5bf.htm

 

Well not really. I have my own design of something like the DTT that I've whipped up in the past, just never had a car that needed it so bad as this Evo. I just ordered the parts to make it, they should be here within a week at which point I'll build and install the system on Erics car in conjunction with the Syncronic to eliminate this god forsaken issue once and for all. If it works(which everything points to it doing just that) you'll definitely hear about it from me.

The DTT is a last ditch effort if all else fails. Eric(EJEvo) knows about it and it's dubbed as plan "C". The DTT looks good on paper, but there's no telling how it will react with the TPS on the Evo, nor how the Evo PCM might react with an electronic device tapped into the TPS signal wire itself. It's a product that's been around since 2004 so it seems and I've yet to find any solid information on it aside from the place where you can buy it I'd say it would probably work just fine, I just don't have ~$85 lying around right now to buy one on a whim and test out.