Thanks for the video link. It does seem less obnoxious. The main difference between the Q and the original seems to be the shape of the exit ports surrounding the piston. The new design has the ports reshaped to flow more in the axial direction.
No one else using one?
OK as far as I know, no one here is using one of these so I am going to be the guinea pig. I perused the net and found a couple of posts in other forums by those using this exact same one and they reported success... Tial Style BOV Flange
I also bought one of their adapter pipes to make the installation easy... T-pipe
On a related note I have a new DIY FMIC going in that should be an improvement in cooling and packaging. It will still be over-the-top. Stay tuned...
OK well the BOV I bought might be a failed item. I was trying to test the opening vacuum pressure using a Mighty-Vac on the banjo fitting. I could not get it to hold a vacuum; no matter how fast I pumped it would not drop below -10inHg or so, not enough to open the valve. I checked the banjo fitting for leaks and that was not where it was coming from what I could tell.
It seems to me with the diaphragm design that it should be able to hold vacuum well enough to open the valve, even with relatively static flow. They even mention using a vacuum pump in their procedure to test for the opening point. Chad, do you think your real Tial BOV seals well enough for this test to work? It works with my knock-off Forge BOV. The Mighty-Vac will pull a vacuum and it will hold the valve open just fine, and it is not even a diaphragm design.
E-mail exchanges with the vendor have not resulted in a solution so I might be sending it back and spending the money for the real thing. Either that or I send it back for an exchange and hope I just got a bad one. Or, maybe this is normal.
I think mine would hold open under vacuum with a mightyvac. It seems to seal well from what i can tell though i've never conducted that test.
I would exchange it and see if the new one works better, if not go old school.
Update: The Tial Q arrived at my house this week. Very nice piece, well made, better than the knockoff. If it works as good as it looks it is worth the extra money. BTW when tested in the same manner as the knockoff valve, the Tial holds a vacuum very well and pulls the piston open; therefore the Tial piston seals better than the knockoff.
I got mine with the 11psi spring. At the rate my turbo return is progressing it will be some time before I test it but I'll post up when I do. I expect that once I get it dialed in it will be a sweet BOV.
Oh yeah I bought it from Travis at Boundary Engineering (forum sponsor); he had the best price I could find.
I wish I could provide an update already. I am still waiting for my turbo and DP/mani to get back. I am getting tired of driving my relatively slow-*** mushy-handling truck and want my freaking car back on-line.
OK I finally have an update. In short, the Tial Q is Megahellastylin. I love it.
As advised by Chad many moons ago I connected the vacuum line to a large port on the manifold; I put a tee in the vacuum line for the brake booster. That apparently helps it open faster, less restriction to pull the vacuum, better flow, makes sense to me. I am using the spring that comes with the Tial, 11 lbs IIRC.
The valve assembly itself is BIG, a lot larger than the Forge type BOV I had in the car before. It took some trial-and-error to find a good spot to work it into the charge piping but I finally made it work. I am using a tee-connector I bought from silicone intakes. It is a 2.5" tee with a welded-on flange for the Tial. A nice piece, and cheap. The wall was thick enough such that I drilled and tapped it for the AIT sensor.
It opens fast and hard, and closes fast. It sounds like something is rupturing open, like a sharp crack rather than a pssssshhhhhhhh. It is more like PSSSHP. It takes a good bit of differential pressure to get it open. At light throttle releases I can still hear the compressor gobble a tiny bit. But this is at really low loads, like less than 3-5 psi boost.
So, though the Tial Q is not cheap, it works great, sounds great, and looks great.
is it open at idle? Also, what is the logic on spring-rates in BOV's?
Nope, not open at idle. Not sure about the spring rates as there does not seem to be much logic to it, and would be highly dependent on the piston/diaphragm anyway. Not sure what 11 psi really means for the Tial.
^^ Yeah I knew about the vacuum-spring chart. What I do not get is what the psi rating means. Only thing I can figure is it corresponds to the differential pressure across the BOV, or in other words the relative pressure between the charge piping and the intake manifold.