ToxicWS6

got most my kit together and should be done tomm, but i got a BOV and it looks VERY similar to this, which nipple should i use and if both which to were? thanks!


http://cgi.ebay.com/ebaymotors/Turbo...Q5fAccessories

ToxicWS6

wow nvm, didnt look at pic that close, pretend the bolt in the top is a nipple also

98Z28CobraKiller

iTrader: (17)

Then what you are looking at is likely a wastegate and not a BOV.

20TA02

iTrader: (5)

im thinking the same... google is your friend...

ToxicWS6

It came in my intercooler kit so I'm pretty sure its a BOV I heard some of the apexi bovs came with 2 or 3 even

ledesordre

iTrader: (9)

sell back on fleabay and get a tial, imo

kmracer

iTrader: (1)

use the one on the top side of the diaphragm, the bottom is for SC'd apps and will remain open at part throttle.

ToxicWS6

ahh cool, ight thanks!

rocket5979

iTrader: (1)

Though you are correct that the OP should use the nipple on the top of the diaphragm I have no idea why you think the BOV vacuum/boost lines need to be hooked up differently when running a centrifugal blower versus a turbo. Even if you are talking about hooking a BOV up into some sort of vacuum bypass valve like what is needed on a twin screw positive displacement blower you would still attach the manifold boost/vac line to the top of the diaphragm but just adjust the BOV setscrew so that engine vacuum can pull the BOV open while in idle vacuum. Not meaning to come off as a jerk, just trying to understand your logic.

ToxicWS6

should i cap off the other nipple then or just let it vent to atmosphere? and may i ask what the bottom does then, or would be used for? just curious

killernoodle

Does the top nipple go into the same chamber as the side nipple?

ToxicWS6

ight (yall are gunna hate me lol) on the top its actually an adjuster nut and bolt for hard and soft, then on the side of the same top piece (its purple so the purple piece, other parts silver) theres a nipple, then on the bottom side of the bottom half silver piece, theres a nipple there too, so would assume separate chamber


this is mine basically

http://www.google.com/imgres?q=2+nip...iw=911&bih=566

kmracer

iTrader: (1)

thats per JGS's instructions. http://www.jgstools.com/turbo/wgpg.html

what they mean by "control boost" i have no idea. i could have sworn it was worded differently a few months back...

rocket5979

iTrader: (1)

You will want to connect your boost/vacuum line coming from your intake manifold to the nipple that is on the top cap that the setscrew is located on. The other nipple on the lower part of the BOV body and thus on the opposite side of the diaphragm will be vented to atmosphere.

The reason the other nipple is there is to allow electronic activation of the BOV via another boost/vac line routed through a computer controlled solenoid that opens and closes and allows the bottom nipple to see boost or vac. Think of the way this operates somewhat parallel to how a boost controller basically is hooked up and operates a wastegate in a turbo system.

Of course the wastegate and boost controller controls your boost in a turbo system. Whereas the BOV prevents a large pressure differential across the throttlebody, possibly damaging the turbo or supercharger compressor wheel, by venting excess boost to the atmosphere after you close the throttle. So even though they operate very similarly in principle they perform very different jobs and interact with different parts of a supercharger or turbo system.

The reason to have an electronically activated BOV varies. The overall reason is if you want to delay the BOV from opening for a split second when the engine goes into vacuum; and thus BOV response time too. And the reverse too when controlling when the BOV shuts. You adjust your tension spring softer than it needs to be and then all fine-tuned adjustment comes through the BOV controller. 90% of people I have ever ran into have never bothered with electronically activating their BOV, but choose to keep things simple and run em mechanically.


I would not base my understanding of how BOV's operate or how they need to be configured based upon one set of instructions that may require a little more concisely written directions.

ToxicWS6

ight cool, and thanks for the explanation, was wondering what it did even if i didnt need it lol, whats teh hard and soft settings? how it goes off whether its one loud PSH and shuts fast (hard) or a slow pshshshshs (soft setting) ? should i even mess with this?

rocket5979

iTrader: (1)

A properly adjusted BOV will open while the need to vent off excess boost pressure exists, but not open under other conditions. It would be a good idea to adjust the BOV for this. The purpose of the adjustment screw on the BOV is not used to modify the sound, contrary to popular belief. If you hear different "cool" sounds then it is probably compressor surge which kills compressors quick! Because I am feeling a bit on the lazy side and don't feel like doing my own write-up I will instead post a portion of an article that I found 5 years ago that decently explained the "how's" and "why's" of BOV's.

"All this screw does is adjust the preload on your BOV spring. BOV's have a small metal plate on top of the spring. The screw screws directly into this plate, compressing the spring. Tightening it (turning it right/in) will compress the spring, increasing the spring energy. Loosening it (turning it left/out) will decompress the spring, lowering the spring energy. (Side note: you can achieve the exact same effect by placing washers/shims on top of the BOV spring.) As you will read below, the BOV spring should be adjusted to the lightest level possible while still holding your BOV shut during high vacuum conditions.

First thing is first: The purpose of the spring in a BOV IS NOT to hold your BOV closed under boost pressure! Selecting a spring based on PSI is incredibly confusing/meaningless and it makes us wonder if the people who pioneered aftermarket BOV design in the first place even understood how they work.

All BOVs have a reference line coming into the top of the BOV from your post-throttle body intake manifold. Under high boost, the force holding the BOV closed is BOOST! The pressure coming through the reference line is equal to the pressure under the BOV piston. Therefore a VERY mild spring will hold it shut just fine under these conditions.

Rather, the purpose of the spring in a BOV is to hold the BOV closed when your throttle plate is closed, IE during idle and deceleration conditions. Under these conditions, the vacuum in your intake manifold is much higher than the vacuum in your intake piping (therefore under the BOV piston) so the BOV has a natural tendency to spring open. Being open isn't even a problem if you are recirculating your BOV into your intake, however if you are NOT recirculating, it can allow unfiltered air into your intake which IS a problem.

Therefore, your goal when selecting a BOV spring and adjusting the BOV should NOT be to select a spring based on your boost level; that makes no sense. Your goal is to get the BOV to stay CLOSED during high intake manifold vacuum/closed throttle plate conditions, using the very smallest amount of spring energy possible. Using less spring energy will allow the BOV to snap open as rapidly as possible when pressure release is necessary.

Remember, the only factor that you can really change is SPRING ENERGY. There are several ways to do this. Less spring energy means your BOV piston will open easily. More spring energy means it will be harder to open and more resistant to opening during high-vacuum conditions. Your goal is to have the lowest amount of spring energy that keeps your BOV closed during high-vacuum conditions.

READ THE STEPS BELOW IN HOW TO ADJUST YOUR BOV:

1. Figure out how much vacuum your car is capable of pulling (peak vac). You can watch a boost/vac gauge while doing a high-RPM deceleration.
2. Using the lightest spring, adjustment screw all the way out, and no shims/washers, install the BOV.
3. Re-create your peak vac in your intake manifold. You may be able to use a vacuum pump or just let the car idle.
4. If your BOV opens during peak vac, increase the spring energy. You can turn the adjustment screw to the right, install a heavier spring, install a second spring, or add shims/washers. Use caution when removing BOV top as the spring will try to throw the top in your face.
5. Increasing the spring energy little by little in this way, you will soon find the point where the BOV is shut during peak vac. Make sure you hear no compressor surge during pressure relief.
6. ALTERNATE METHOD: Let your car idle with the BOV installed with the lightest spring, adjustment screw all the way out, and no shims/washers. Using methods above, find the lowest amount of spring energy that will keep the BOV closed at idle. Since most cars pull more vac during deceleration, increase the spring energy by "some". We don't know how much "some" is because it varies from car to car, which is why we recommend the method above if possible. Make sure you hear no compressor surge during pressure relief."

ToxicWS6

hmm, cool, thanks for the wright up!, ill have to go out and mess with it one day make sure its not doing anything weird then lol, thanks!