bov question with the bosch 103

[BrandonW]

ok so i bought a bosch 103 bov (not brand new but in very good shape and only used for about 3 months from the previous owner)

when i took my car for a spin (i couldn't really open it up full throttle because it was raing/wet out and kept loosing grip even with my 9.5 wide tires haha)

it seems like i stopped the flutter by getting the other bov but now it seems like when im driving and make a little boost and let off the throttle (when it goes to the 0 from -4 on the stock boost gauge) i get the weird woooh noise like the bov doesn't completly open but if i make more boost i hear it blow off like psshhh and everything is fine

maybe its not such a bad thing because it only happens when im letting off the throttle to not accelerate to fast

but i wanted to ask whats going on, is the bov leaking?

should i worry about it?

 

[Poodles]

How is it installed?

The bosch BOV is know to sound like it's hooting, so it might be normal...

 

[aye mate]

http://www.supramania.com/forums/showthread.php?t=1805 check out this thread I made a while ago. The 103 does hoot alot.

 

[BrandonW]

http://www.supramania.com/forums/showthread.php?t=1805 check out this thread I made a while ago. The 103 does hoot alot.

haha it hoots (so it seems like its leaking? but only at lower psi? or can i just not hear it leaking when more boost is applied?)

i forgot to mention that im running stock to somewhat over stock boost, i haven't hit fuel cut yet and don't plan on it

mods: apexi intake and 3in exhaust turbo back

and some of those links wern't working i know i have it installed right and when it was delivered it was already set up the hoses were on and all

 

[Pantaloon007]

That brings a question to my mind- my BOV does the "flutter", but so does every other MK3 Ive ever rode in. Is the flutter a sign of compressor surge, or are you canging it for personal preferance?

 

[BrandonW]

That brings a question to my mind- my BOV does the "flutter", but so does every other MK3 Ive ever rode in. Is the flutter a sign of compressor surge, or are you canging it for personal preferance?

well i changed mine because it seemed like it was fluttering alot and as far as i know it was the stock bov that has been on my car since 89 and now with 212,000 miles on it so i just wanted to be safe

but fluttering is a sign of compressor surge

 

[aye mate]

If you take off the stock BOV or any BOV for that matter and you can blow through it. It is shot. That means its closed and when the vac. line is attached to it it will be open and allowing air to re-circ. Then when boost is made it will push the valve closed and not allow air to re-circ back to the accordian hose..

 

[Rennat]

well i changed mine because it seemed like it was fluttering alot and as far as i know it was the stock bov that has been on my car since 89 and now with 212,000 miles on it so i just wanted to be safe

but fluttering is a sign of compressor surge

how is fluttering a "sign" of compressor surge? i have a greddy bov that flutters at 1-3psi, but as soon as you get on it, and you shift, no flutter.

 

[CajunKenny]

^^ Yeah, every BOV that I've had on my cars (aside from stock) has fluttered at throttle let off under low boost. I ran the Bosch 103 for a while too and experienced 'flutter'.

Based on "my" experience, I would say that it is normal.

 

[BrandonW]

well i know the stock bov was fluttering even at higher boost like between 6 and 10 so i just replaced it

 

[black89t]

If you take off the stock BOV or any BOV for that matter and you can blow through it. It is shot. That means its closed and when the vac. line is attached to it it will be open and allowing air to re-circ. Then when boost is made it will push the valve closed and not allow air to re-circ back to the accordian hose..

are you sure about that one. i'm pretty sure you aren't suppose to be able to blow through it while there isn't any vacuum going to it. hints it's not leaking. i'm dam near positive that its only suppose to open under a good vacuum pull. like when you boost hard up the rpms then let off. if you have good vacuum w/o any leaks it should hit 28"hg. that is why if your in low rpm and boost up until maybe 3k then let off it tends to make more noise. reason is because the car doesn't pull as much vacuum compared to a full pull then a hard decel, so the valve doesn't open as much. i could be wrong, but that was my understanding of a blow off valve. i don't see how it would build boost quickly if that thing was partially open all the time until boost is made.

 

[aye mate]

are you sure about that one. i'm pretty sure you aren't suppose to be able to blow through it while there isn't any vacuum going to it. hints it's not leaking. i'm dam near positive that its only suppose to open under a good vacuum pull. like when you boost hard up the rpms then let off. if you have good vacuum w/o any leaks it should hit 28"hg. that is why if your in low rpm and boost up until maybe 3k then let off it tends to make more noise. reason is because the car doesn't pull as much vacuum compared to a full pull then a hard decel, so the valve doesn't open as much. i could be wrong, but that was my understanding of a blow off valve. i don't see how it would build boost quickly if that thing was partially open all the time until boost is made.

I think we are saying the same thing. With no vac pulling the valve(IE when the car is off or the valve is taken off it should be closed, but if it is open the BOV is broken. Thats what I was saying.