bov or diverter valve? i know

[Paul]

I did some searching and was wondering if anyone had any other info.
i know the car has a diverter valve stock but why does everyone switch to a bov? is there more of an advantage to one vs the other?

I plan on doing a fmic either begi or hiboost in the next few weeks, so what should i go w/ ? bov or a dv?

i know this is like beating a dead horse, but i did some searching already.

 

[jeffmsp]

the stock bypass valve will leak boost over ~8-9psi. With my mbc set at 12psi, and the stock BPV in i spike 12, then quickly down to 8-9. with my forge Blow off valve the boost holds where its set at more or less. If you are not looking for any new sounds "pssssst every shift" then grab the forge bypass valve, it wont leak boost and doesnt make any new sounds.

 

[Paul]

i'm just looking for something a bit louder. I'm not looking to boost over 8-9psi. I dont' want to be spiking at all either. I want to keep the boost low until next year when i can do a piston rod combo. I just wanna play it safe for the first year.

EDIT: i know i'm a n00b so excuse me for this question.
but i thought that the wastgate was the thing that holds the boost and that the bov just recirculated the air?

 

[jeffmsp]

yes. the wastegate is what sets the boost level. With a manual boost controller you adjust the psi by changing the amount of vacume the wastegate sees. although the bpv is not directly related to the wastegate, by leaking air it does not allow higher boost levels to be run. to comn\press air you need a sealed system. when the bpv starts leaking air the psi decreases. (because it is only designed to seal stock boost levels) if you throw on a boost controller and boost up high the bpv cannot hold the pressure and begins to leak air.

 

[TX Speed Demon]

^^ hmm, I wonder if this is why I can't see over 5psi on my set up. After installing the FMIC and recirculating the Greddy the boost dropped from 6 to 5psi and adding a bigger downpipe and catless midpipe had no effect on boost levels. It still spikes at 7, but never holds more than just a hair over 5. I'm going to have to tighten the valve spring and see if I get my boost back.

EDIT: Wasn't the BOV, my car just has low boost. Got an MBC on there yesterday and am holding between 6-7 now with no adjustment to the BOV.

 

[mspeed101]

Why not get both? Im running the turboxs dv and greddy type s and love it.

 

[CasopoliS]

Recirculating is ideal for low boost applications (bypass valve)... some tuners don't even vent with BOV, recirculating reduces lag and increases response time. I have had both a dual valve setup (BOV and bypass valve), and just the bypass valve. I think it drives nicer with just the bypass valve, but I am still toying around with the setup. Get a new BPV for now, to replace the stocker. Later when you get an FMIC or hardpipes get a flange and a BOV.... now you will have a few options as to what you want to run. I would say do not vent only....recirculate some of it.

I am getting the Boost Sciences Reflex bypass valve in the mail within the next few days. As for the specs, it seems nice....I will let you know what I think of it. Forge would be the other recomendation.

 

[daedalus]

Why not get both? Im running the turboxs dv and greddy type s and love it.

Ditto on that setup. Except for the running part.

 

[Paul]

i had no idea you could run both. anyone have pics?
any kind of bypass valve that would work on the stock setup? and that i just have to get a flange for when i get a fmic?

 

[mspeed101]

i had no idea you could run both. anyone have pics?
any kind of bypass valve that would work on the stock setup? and that i just have to get a flange for when i get a fmic?

heres a pic of my set up. You can make the turboxs or boost sciences bypass valve work on the stock setup

 

[Paul]

what would be the advantage of using both? and would just the bypass valve sound like a turkey or would it sound kinda like the stock bpv and still sputter?

 

[CasopoliS]

what would be the advantage of using both? and would just the bypass valve sound like a turkey or would it sound kinda like the stock bpv and still sputter?

More than likely just the bypass valve will give turkey. People like to 'kill' the turkey noise under the hood, so the first option that comes to mind is a BOV venting to the atmosphere. This give a nice whoosh every shift, the sound Fast and Furious made so popular. The problem? Our cars have a MAF system, meaning a sensor at our intake is telling the engine the amount of air it is about to see. Well, when you have a BOV venting that air, the engine does not get the air the MAF said it would.... and you stall upon fast deceleration after shifts. (This is assuming the MAF sensor is before the BOV, and it is on a stock setup). The solution? Get a BOV and a BPV. Now when you shift you will still get that whoosh (and minimal to no turkey), but now without the worries of stalling because the Bypass valve is recirculating some of the built up pressure back into the system. The engine wont get as much air as the MAF told it, but enough to keep it from stalling.
Of course recirculating all the air will most likely cause the turkey (like stock setup), but increases response time and spool-up after shifts (in some cases). Your best bet is to play with both setups.....but always reciculate some of it. As long as both the valves are on the pressure side (duh), it should work regardless of their location. If you put the BPV on the turbo->IC pipe, then its ideal to put the BOV on the IC->throttle body pipe, and vice-versa. If you have the space, you can put the both on the IC-> TB pipe. I guess dual valves is what people on the forum love and have had good results with, so I would go for that.

 

[Paul]

thanks for the info.
the car has a sputter to it stock and i would like to keep it like that just a little bit louder on the stock setup for now.

 

[peepsalot]

I have a mitsubishi BPV that I got with my begi fmic. Not sure if they all come with it. I got mine second hand, and it is supposedly the prototype. Anyways, it works well enough, and eliminates turkey.

 

[CasopoliS]

I have a mitsubishi BPV that I got with my begi fmic. Not sure if they all come with it. I got mine second hand, and it is supposedly the prototype. Anyways, it works well enough, and eliminates turkey.

Is this BPV on the turbo->IC or on the IC->TB? What intake do you have? Thanks. I am interested in recirculating with no turkey....tried a few setups with no luck. Thanks.

 

[peepsalot]

Same location as stock, turbo to ic pipe, I have AEM CAI w/ apexi filter, converted to SRI style. The bpv is MUCH larger, and the nipple on the hardpipe is bigger than the stock one. Then there is a reducer to make the tubing fit from the bpv back into the intake.

 

[CasopoliS]

Same location as stock, turbo to ic pipe, I have AEM CAI w/ apexi filter, converted to SRI style. The bpv is MUCH larger, and the nipple on the hardpipe is bigger than the stock one. Then there is a reducer to make the tubing fit from the bpv back into the intake.

Thank you. When I get my Boost Sciences Reflex valve that is the first setup I am going to try. My nipple on the hardpipe is stock size though, so I will need two pipe restrictions. I wish I would have known about this upgrade when I welded the 19mm nipple on. I have an Injen CAI which I also want to make SRI. We will see.