DSM BOV questions

[89CSX#179]

Why is it on my friend's GST when we unplug the line that goes from the BOV into the intake track and plug it, his car will begin to cut out and die?

[GLHNSLHT2]

cause the boost is probably pushing the diaphram open which pulls more air through the MAF and makes the puter think the car is using more fuel and floods it out.

[89CSX#179]

is there anyway we can fix this? we did it again yesterday and it didnt die once on us, but we would like to keep it from happening forever

[GLHNSLHT2]

convert the car to a Speed Density Fuel system like Turbo Dodges use, or just plumb it like the factory intended.

[Darkapollo]

you are wrong. it has nothing to do with pressure, it has everything to do with the MAF sensor. think about it, if the boost was pushing open the valve, wouldnt the air just escape? YES. i have a 1g RV/BOV on my sundance and under light load it whistles because that is what is happening. the valve is seeing vacc and allowing the slight pressure to push it open and the air is escaping.

Now, to give an answer.
it uses a Mass Air Flow sensor(MAF). its that box that is right by the filter before the turbo.
basicly it reads how much air is being sucked into the turbo and engine and calculates the fuel need based on that.
when you remove the RECIRCULATION tube from the RECIRCULATION VALVE suddenly all of that already measured air is not getting into the engine. however, the fuel still is. causing an extremely rich condition which is killing the engine.
THE ONLY 'good' way around that is to place the MAF AFTER the RV/BOV. however, as DSMs are set up to read vacc at the MAF, or in laymans terms, it is a 'suck through' design, you will need to change that to a 'blow through' type of MAF. That is really more work then its worth. just get a different RV/BOV and stick that tube back on to the intake pipe! that cool 'pish' sound is not worth the hassel of changing those expensive (the MAF on my eclipse costs $175) sensors and the supporting hardware (because you will need a GM MAF converter so the ECU will understand what is going on). a Greddy Type S hooked into the recirc system will still provide that 'pish' sound, it will be a bit muffeled but you will be able to hear it.

there are a few ways to go about it if you are still stuck on the 'need' to screw with it (DSMs have enough problems, they dont need more, and YES i own one so i CAN talk)
the expensive Greddy E-Manage will allow for an 'anti-stall' fuel cut that will keep the engine alive during boost vent.
the already discussed GM MAF 'blow through' w/ interpritor conversion.
using a 2 or 3 BAR MAP sensor and interpritor.
that is about all you can do that i know of.
It really is not worth it. not just for that 'cool' sound.

[NJ87ShelbyZ]

Darkapollo is right on every count.... The best solution which was also said, is to change the car over to speed density system (impliment a HKS VPC) and then you can run an open BOV w/o a problem.

Just out of curiosity, what type are you using and why would you want to run an open BOV, becuase it sounds cool? Just keep it setup the way it's supposed to be and you'll be fine.

[Ondonti]

Best solution is to keep it simple as was said, not change to a speed density.