Thread: cool product

at idle I get that, but what I'm thinking of is at cruising speeds when it's at vac. If the throttle is open and there's vac in the intake mani, there is also vac in the intake piping, no?

If there is the same vac on the vacum hose side and in the intake piping, you have an equal about offseting themselves so the spring takes president. So the BOV stay shut.

I still don't understand why people don't just recirculate the blow off valve?

Mostly just out of pain in the butt for me. I always struggled with it leaking, being a hassle to run, etc. My bov is under the driver's side fender, which makes it a pain too... one of the reasons I went to blow thru was to eliminate that hassle, among other reasons obviously. We'll see if there's any improvement with this piece, otherwise, I guess I have squandered $50, huh? I've never had any stalling with the blow thru setup obviously.

There's always been a big debate between those that think the BOV will allow air to be sucked in, and those that don't. It seems those that don't fall into two categories. 1)They think it can't be possible, as the BOV is "not supposed to" do it. 2)They think it can't be possible, because they believe there is no time when there is enough pressure difference between the BOV signal line and the charge pipe when the throttle is closed to overcome the spring pressure unless there's air to be expelled (Andreas's theory above).

Those that believe it will take in air (and usually put filters on their BOVs) have heard secondhand from independent experimenters (I know of one in the turbo Dodge community), or have done an experiment themselves. One way or another (sometime by attaching noisemakers that make different noises based on "sucking" or "blowing") they have determined that under normal operating conditions the BOV can suck in air for split seconds or longer immediately after quick throttle opening or during some idle conditions.

I'm with Andreas where I don't believe it is possible due to knowing how the BOV works. I tend to not believe the experiments because well, I am a hard man to convince. I've gone back and forth on this topic though, and can only recommend you do a controlled experiment yourself and shed some more light on the subject.

Well I did some experimenting by measuring the vac at cruising speed and then using a hand vac pump to simulate that same level of vac with the valve off the car. I know that doesn't take into account the pressure of the charge pipe, but in my little off-the-car experiment the valve opened with less vac than I was running at cruising (I don't remember the numbers anymore). It had always been in the back of my mind, so when I saw this product from ATP I liked it enough to grab one. On one hand, it may be disputable, on the other, it can't hurt to close any openings, right? Won't hurt me, and I know people on here other than myself have wasted $50 before, right?

You hit the nail on the head right there as to why that experiment in null and void. The BOV works on a pressure differential across the valve. Under normal cruising there is vacuum on one side of the valve, and basically the same amount of vacuum on the other side (signal line) which ends up being a zero differential. Of course it opened when you applied vacuum to the signal line and not to the pipe side of the valve.
Highly effective BOVs have very weak springs which are easy to overcome in this manner which is no doubt what happened here.

very true. I realized when I tested it that the test was not accurate, but I was really testing it to make sure that I had a good adjustment. I'll just stick with $50 worth of peace of mind for my new disco potato and avenir, how's that for reasoning?