2G Question About BOV vs BPV

[Brandonn]

So this is my question. I have search for 3 hours or so on Google, on here, and on other forums as well like MazdaSpeed and im still unsure of what im looking for. So far i have read that BOV release the pressure into the air and that bypass valves send the pressure back into the intake system. My car came with a knock of Greddy BOV and im looking to put a for to prevent any issues. I cant find one for sale though and through out this forum i have just read up on people using BOVs. I also read up about people "venting the bov into the atmosphere" but doesnt a bov already do it by default?? Thanks anyways

 

[pauleyman]

Bov and bpv are just different names for the same thing. Whether or not you recirculate to the intake is a function of the design of the valve and how the car is setup. Dsm have a mass air sensor stock and require that you recirculate. Now there is such a thing as a popoff valve and I have heard people call a blow off valve a popoff but that technically isn't correct. A popoff is a valve on the intake manifold and designed to "popoff" at a specific presure as a failsafe. Back to the original topic, if you run a mass air sensor prior to the turbo you must recirculate.

 

[EC17PSE]

No as we have a maf it calculates the air, so venting it is bad because its expecting to see this air even when recirculated, depends what outlet you have but most greddys recirc, i had a type s bov and it has both options but recirc is how it comes,

Others like tial or some of them dont but some can be added after.

So just make sure you keep it recirc u till you have a gm maf or speed density,

Do you have an engine bay pic to show us

 

[Brandonn]

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[EC17PSE]

Yes many copys of your engine bay , delete some but keep 1.

It is recirc so i would not worry, its working just fine as it is

 

[Brandonn]

Thanks for the help. And sorry i dont really know how to use this yet

 

[EC17PSE]

Hey nk worries, took me a while to figure it out on the old system and it was not as easy

 

[PlanZero]

I would keep an eye on classified or your local Craigslist for a used real GReddy since you already have the flange for that. I got a used S type and hard upper pipe for $60 of CL a couple years ago.
Those eBay BOVs are know to leak and tear diaphragms , but there are videos out there of how to replace the diaphrahm with a bicycle tire or something similar.
Also I believe the NRG (someone correct me if I'm wrong) replacement diaphragms fit Greddys and their knock offs.

 

[Brandonn]

I dont really need a bov right since my car is pretty much stock

 

[EC17PSE]

I dont really need a bov right since my car is pretty much stock

Well you do otherwise your excess pressure when the TB closes has no where to go! So it will go back through the system and to your turbo!

 

[PlanZero]

A blow off valve is the same as a bypass valve. Whether it's OEM or a $20 eBay bling turd you need it, and it needs to be hooked up properly.
If your knockoff isn't leaking and seems to be functioning properly it's fine for now.
Take some time and learn how forced induction works on a DSM. Do all necessary maintenance (timing components, cooling, drivetrain, suspension, etc) before anything else. I see you're a college kid and if you are broke like I was you can still build a real nice ride for a few thousand utilizing your parts car, classifieds, rock auto and eBay. Don't skimp on engine or turbo but buy used whenever possible. Do a ton of research before buying anything.

 

[Brandonn]

Alright thanks for the advice guys. Will do a boost leak test after i get my car back, currently at the shop getting a full engine and transmission rebuild.