BOV sizes

[Draven]

yah, $320 is the price my local is charging, which seems to be pretty good

[Endless]

Just don't run one, dose it bro..

[ReQuieM]

How much difference is having the BOV on the TB side really going to make?

I was about to weld on one on the turbo side (for the added stealth factor) but I mean if its going to make that much difference then I'm sure I can make something to hide it on the TB side.

30psi etc: How does the AVO one work? the HKS SSQV I used to have was set up so the pressure in the pipe held the bov shut, so I couldn't see any physical way for it to leak. It needed vaccum in the second chamber to pullit open, which also had a spring to hold it shut. Is it the same with AVO?

Just trying to get my head around how it could be forced open...

[BigWorm]

$320!!!
Damn, I just picked up one of those GReddy Type R jobbies (the big arse suckers, 40mm piston, I have one on the 4A, BvD has one on his p00 grenade) for $150. It's second hand, but retail's something silly like 380 or so.
I just can't fathom spending over $200 on a fuckenwoosh valve....

[Norbie]

All BOV's are a simple piston which rely on a pressure differential to open. Equal pressure = spring holds it shut = no leaking. This is why I contend there is no difference in performance between any reasonably well constructed BOV, unless you're talking some massive single turbo setup with eleventy billion hp, in which case you might need to think about the outlet diameter.

Of course the value of having any BOV at all is highly debateable, but that's a discussion for another thread.

[JustCallMeOrlando]

I'm thinking of getting a BOV but not for the noise, I want it for making it quieter. Was driving around some hills roads the other day and f**k me the car is loud when I get off the throttle.

[ganador]

How much difference is having the BOV on the TB side really going to make?

I was about to weld on one on the turbo side (for the added stealth factor) but I mean if its going to make that much difference then I'm sure I can make something to hide it on the TB side.

30psi etc: How does the AVO one work? the HKS SSQV I used to have was set up so the pressure in the pipe held the bov shut, so I couldn't see any physical way for it to leak. It needed vaccum in the second chamber to pullit open, which also had a spring to hold it shut. Is it the same with AVO?

Just trying to get my head around how it could be forced open...

i would think anywahere from the turbo to the throttle body would be fine cause theres always boost there, just not after the throttle body , wont be doing much there from the vacume haha

[ganador]

I'm thinking of getting a BOV but not for the noise, I want it for making it quieter. Was driving around some hills roads the other day and f**k me the car is loud when I get off the throttle.

loud in what way

[chris davey]

$320!!!
Damn, I just picked up one of those GReddy Type R jobbies (the big arse suckers, 40mm piston, I have one on the 4A, BvD has one on his p00 grenade) for $150. It's second hand, but retail's something silly like 380 or so.
I just can't fathom spending over $200 on a fuckenwoosh valve....

Took the words right out of my mouth.

I got a mega fu(ken whoosh valve new for $150 or so. GFB. Yep, its illegal just like everything these days.

[ddeane]

Draven

Most likely in line with what others have said - the BOV has to be big enough to vent the amout of air that the system has in it without spiking.

Plumb back should be fairly quitt so should not be an issue.

As to what you purchase I think that you will get all types of opinions. Maybe to give an idea of what I have done will help.

I have a 1ggte single turbo running about 12 psi (200+RWK). On advice from my tuner I am using a inexpensive Bosch 25mm (1 inch) BOV. Also on his advice I made sure that I could fit another of these to cater for increased boost in the future. I understand that on his Torana drag car, running a huge turbo and heaps of boost, that he runs 4 or so of these BOVs.

So if you are not too worried about apearance, and want to keep the cost down and still use a good unit you might like to consider the Bosch. By the way you have to listen carefully for the BOV venting back.

Craig

[EVOSTi]

from memory the bosh valves are only like $50 new? either way they are extremely common and easy to get from any euro wrecker.

[Mr Ed]

How much difference is having the BOV on the TB side really going to make?

Well my understanding is that the line going in the top from the plennum has to feed the same pressure as what the valve is getting from the pipe it welded too. (Ie, when you throttle snaps shut the plennum pressure drops and your IC pipe pressure spikes...pressure difference opens valve)

This means that if it is installed before the IC there will be a pressure difference even on WOT as the IC is a slight restriction and pressure builds up in the IC pipe before it. This means you are relying on the little spring to hold the valve shut which generally isnt designed to do so and if the pressure difference is more than a couple psi you get boost leak.

My 2cents anyway.

[Mr Ed]

i agree totally ... i use 2 also one on each side of the IC and theres hardly any noise

what i CANT understand is how can blow off valves blow open?? the pressure pushing it open is matched by the same pressure on top pushing it closed plus the spring also pushing it closed so they will always stay shut, unless the throttle is partly or fully closed in that case you want it open!

2 valves will still open on closed throttle as even if the IC pipe has atmospheric pressure in it(lowest possible pressure), the plennum has vacuum(less than atmospheric pressure) in it when the throttle is shut. Still a pressure difference on both valves, therefore they will both open.

(I hope that helps??)

[Draven]

the whole reason I'm installing a BOV is to reduce the noise... so anything that is cheap and works is my friend.
My only problem with bosch is that their australian customer service SUCKS. I e-mailed them asking what the part number was for their biggest BOV (as the australia site doesn't list BOVs, and the german site has crappy navigation), and they just pointed me to their website... which is where I got their farkin e-mail address from </rant>

but yes, a 40-50mm bosch plumb back would be perfect

[Mr Ed]

the whole reason I'm installing a BOV is to reduce the noise... so anything that is cheap and works is my friend.
My only problem with bosch is that their australian customer service SUCKS. I e-mailed them asking what the part number was for their biggest BOV (as the australia site doesn't list BOVs, and the german site has crappy navigation), and they just pointed me to their website... which is where I got their farkin e-mail address from </rant>

but yes, a 40-50mm bosch plumb back would be perfect

Multiple stock BOVs found for free??