Installed my synapse bpv today, went to go drive the car around and datalog and Ive noticed I lost about 2 psi when I spike...when I let the boost ramp up (driving in a higher gear and loading it up down low in the rpms) itll build up boost upwards of 20psi no issue. The REAL issue is when I row the gears wot, in 2nd gear I hit 26psi and then when I shifted to 3rd it only came back to 15 psi and the car fell on its face. Any ideas what could've happened?

All I replaced was the bpv, I have the Evo verson of the synapse so the c port is closed off, I tee'd off where the factory bpv was for the a and b ports. One thing I noticed is the vacuum hose (4mm) is slightly loose on the nipples...I installed two zip ties around the nipples of the bpv to tighten it up but I can kinda spin the hose on the nipple with my fingers...no matter how tight I make the zip ties. Theyre not loose enough to be able to be backed off...just can kinda spin them on the nipple a little.

 

Not for nothing that's worst bov in my book sell it and buy a tial...

 

Oh, here comes this guy again???? He seems to add useless comments to everyone's posts. I would check for boost leaks and go from there.

 

I just don't get why it'll hold boost in the first gear that I floor it, then when I let off to shift the next gear looses 10psi give or take. I did it in 2nd and shifted to 3rd, did it in 3rd then shifted to 4th and the next gear always falls on its face. I logged a little and its not knocking.

 

Mine holds boost better then my stocker crushed did. If your dropping boost you better check for leaks including all the hardware and fittings on your BOV. I also was retuned after installing mine and that made a difference in drivability as well. I run "B" port by itself and "A" I left VTA.

 

It seems to be a recovery issue, when I shift the boost drop is 10 psi and then it has to rebuilt again...this is on a stock turbo, it never happened on the stock ix dv so Im wondering if its a vacuum issue or maybe somehow I got a faulty unit? I boost leak tested with the stock and held up to 28 psi no problem, all I swapped out was the synapse valve...I dont think a leak would cause the huge loss between gears, if I let it ramp up in one gear it holds boost fine.

 

When I received my synapse, all of the barbed fittings were loose. Did you go and tighten everything before installing? Tighten every single fitting on that whole BOV and it will hold like a champ.

 

I have C port hooked up to a boost source off my licp i believe...

 

I got the evo version so I only have the two nipples, and yes they were both loose and I tightened them up...the center nut next to the barbs doesn't have to be touched does it? My main concern is the recovery between gears...why am I losing 10psi when I get back on after the shift?

 

I left the preload adjustment screw (small allen) ...backed out.... as it should have come to you new. You can make small adjustments to it but I don't think it is going to help you keep boost between gears. The boost loss between shifts is normal as that is the purpose of the quicker responding valve. The only way I know of to maintain boost between shifts is to NLTS (No Lift To Shift) ... faster shifts in other words. Engines cannot develope boost during deccel.

 

Well if you are having boost loss wouldn't you want to increase your spring pressure then to maintain constant boost pressure

 

The shuttle cylinder design used with this BOV doesn't work like the other diaphram designs. Typically with those designs you would do that. This adjustment dampnens the cylinder response to a varying degree. I found if adjusted too much you start effecting part throttle response too much. Also not all cars are set up the same so its more up to you to tailor the response the way you like it.