Vaccum & BOV Q

[smp3000]

Yo Yo Yo., Happy new year to all of you!

I have two questions that might be dumb, but I'm curious.

First: At what psi should the BOV purge the air? I understand the dynamics of it, but wonder sometimes if I have the screw on too tight or not tight enough. If I boost at all, even 1psi it will surge.

Second: I noticed that on my boost guage (greddy electronic in MmHG) That the Vaccum isn't ever at max Vac. I can't remember the exact reading but it's about half way. Is this correct? Or should the vaccum be stronger?

 

[LinuxRacr]

Scott,

Everytime you cross the boost thresshold (past the 0 mark on you Boost Gauge) you enter the realm of Positive Manifold Pressure. If your BOV is purging, it is doing it's job, because if you have positive manifold pressure, and you let off the gas, you want that backpressure directed away from the exit side of the turbo. It is doing what it is supposed to do.

Your boost gauge at idle is at 20 in vac. That is normal, I don't think I have ever seen my gauge go all the way to the max vaccum at all.

One last thing.....YOU ARE PARANOID!! But with boost, that's a good thing! (thumb)

 

[smp3000]

Bahahahaha

Yes, I'm totally paranoid. It's not so much that I was worried, it's that I'm wondering if I'm possibly being jipped out of some power by doing something dumb or not doing something smart.

 

[chdesign]

BOV are different. I'm not sure about the FM BOV but I am goign to be runnign a pull relief valve which will open ANYTIME that there is pressure on teh BOV side and vaccum on the manifold side. Some BOV's like alot of the TurboXS and ones like those are just spring valves that take quite a bit of pressure to get them to open. My old TurboXS would barely open at 5 PSI anythign under that you were lucky if it opened at all. It sounds like the FM BOV is a pull relief so you shoudl be fine just chill out and stop being paranoid lol if your that worried back it back down to 7 psi man.

 

[smp3000]

Honestly I'm not worried. I just was wondering about it, and thought I'd ask. Like many of the others that installed the turbos by themselves- I don't know anyone else out here that has any experience with forced induction. So if I have any questions I bring them to the board.

My car is running great at 8.5 psi.

 

[chdesign]

Cool deal man I'm just goign to run 5 psi for the time being since i'm non-intercooled then i will figure out how in the crap I want to do an intercooler lol.

 

[LinuxRacr]

BOV are different. I'm not sure about the FM BOV but I am goign to be runnign a pull relief valve which will open ANYTIME that there is pressure on teh BOV side and vaccum on the manifold side. Some BOV's like alot of the TurboXS and ones like those are just spring valves that take quite a bit of pressure to get them to open. My old TurboXS would barely open at 5 PSI anythign under that you were lucky if it opened at all. It sounds like the FM BOV is a pull relief so you shoudl be fine just chill out and stop being paranoid lol if your that worried back it back down to 7 psi man.

Yeah, the FM BOV does the recirulating, and it expunges. Best of both worlds! I love it!!