slivicslpr

the dsm valve is not a blow off valve, its a diriviter valve, at low idle when the turbo is not making enough pressure the engine is asking for more air then the turbo can supply. then the diriviter valve with a pop-et type valve allows air pressure to enter the intake tube. then when no more pressure is needed it closes. when you let your foot off the gas abruptly the popet valve goes up from the pressure and give you your WOOOOSH sound. releasing to the atmosphere or back to the tubo inlet, what ever you wanted it to... if you have a "bov' from a stock car, its acctually a DV valve and i suggest you add i filter to the end to you dont suk ---- into your motor.

Owned

highschool, you need that.

crxrx7

I don't remember learning that in high school. In fact all the ---- that I use most I learned on my own or out of high school. except for the numbers and english stuff that I use everyday. Wait a minute I confused

sohcrxsi

i dont even have a filter on my turbo inlet

Anti-NA

that is really stupid, unless you crawl down under your car and cover up the intake/compressor inlet, it is not going to "suck" in anything so there is no need for a filter on it.

quadnie

I feel like making this one a sticky for everyone to throw in their 2 cents. Good reading.

d16forlife

Your right quadnie.This is some good reading.

Sem you are right about the dual diaphram BOVs.

Deverter valve is the correct name for it though.Calling it a blow off valve is like calling a supercharger a blower.If you think about it a bov is just diverting the presurized air into the atmesphere.

True diverter valves like the bosch are used on turbo cars with mas/maf.This is becouse the air needs to re routed back into the charge pipe that goes between the maf/mas sensor and the compressor inlet.


The fact of the matter is that no matter what you want to call them they open at vacume.The diaphram inside works completely opposite of a wastegate wich opens at a set psi.

quadnie

I'm kinda having a hard time grasping this "open at idle" thing. Let us use a 2g dsm for reference, since the placement of the MAF and the routing of everything is pretty simple.

If the 2g bov (someone said it was a "bosch style"?) is open at idle then it can't be sucking in any air since all the air flow is being sucked from where the compressor is. Otherwise it would be just fighting for air suction?

And if all thse single diaphram BOVs suck air at idle, man the dsm guys are really ------- their cars up, the MAF is what meteres the air to the computer, the injectors compensate exactly for it. So that means the cars are leaning out at idle?

contribute guys

quadnie

Ok, I changed the thread title and made this a sticky (in hopes to get some more input on the issue). I'll leave it stickied for a few days so everyone has a chance to throw something in.

If anyone minds me changing the title, it can easily be changed back.

-ryan

92notec

All DSMs, whether 1g or 2g run their BOV the same. The valve IS open at idle, but the air drawn in by the BOV is compensated for by the MAF. If you look at the pipe coming off the BOV, it is routed back into the compressor intake pipe DOWNSTREAM of the MAF. Thus, whatever air is sucked through the BOV has already been calculated and doesn't cause a lean condition. Because of the way this BOV setup works, a DSM will do one of two things if you disconnect the pipe going from the BOV to the intake pipe. If you just take the pipe off and do nothing, the car will run like complete ---- because there's a big gaping hole after the MAF that allows air to bypass it. Second, if you plug that hole up and disconnect the pipe, it will run a little lean under vacuum, which may or may not matter depending on your setup.
Overall, I'm pretty happy with my 1g DSM BOV. It's got an interesting sound that's not too loud. I've just learned to deal with the constant whining and whistling every time I let off the gas.