Type RS BOV

[MrBentley]

Sup evderybody. Well i am having a newb day today so please don't trash me for asking this.

I just recently got a greddy Type RS bov and i noticed that there is a little nut on the top that, which i belive is the adjustment for how stiff the spring for the valve will be. Now if im correct then adjusting the spring will adjust how much psi I will be running.

If that is true then why would i need a BC (manual or electronic) when i could easily just use a wrench to tighten or loosen the nut? Or am i totally off the mark here?

 

[Flash]

The BOV doesn't control PSI levels. It just holds boost. The spring is there for you to adjust when the BOV opens. You would want it on a stiffer setting if your running high boost and you don't want it blowing open and releasing all the boost. Basically, the BOV holds boost. It doesn't adjust the boost levels.

 

[MrBentley]

Okay so the spring stiffness is for like saftey or somthing? and then when adjusting boost you have to not only use a boost controller but also adjust the spring?

I guess im still confused about the whole bov/psi issue.

 

[Flash]

The spring isnt there for safety.
And you don't adjust the BOV spring when reaising boost with a MBC.
I don't think the spring really does anything really (HKS removed it off the 2g of HKS BOV's) Ok, I'll try to explain in a less confusing way. If my spring was too tight my BOV would never open. If the spring is set too loose and it would probably just blow open and release the boost.
Someone correct me it I'm wrong.

 

[hystericfox]

Flash is right, but let me explain his post a bit more.

You might have to adjust the spring when you raise boost pressure. If your BOV started to blow open at 15 pounds, and you decided that you want to try 20 pounds, it will obviously open at the higher boost pressure. The spring adjustment controls at what point the BOV will open. If you set it soft, it will blow open at higher boost levels.
If you set it too hard, it won't open under lower boost levels, and surge the compressor. You want it set so that you have enough vacuum to open the valve. I have an RS on my car, and I turned it about 2 turns in, and the only problem I've had with it so far is that when I was having trouble with my MBC, it blew open at about 22 pounds (according to my gauge). The MBC was supposed to be set at 15, so it was never a problem up until that point.

It does need the spring because it closes the valve. I believe that HKS uses diaphragm instead of a spring. They also tell you that when it starts to leak, you have to crush it, like the 1G BOVs. You still can run into the problem of vacuum to open the valve if it's crushed too far.

 

[MrBentley]

Well then im just a idiot cuse i still dont get it.

So the spring is there so that you can adjust at what psi it can handle before blowing open meaning that if you have higher spring tension, the valve wont open until a higher pressure is reached but at the same time it could cause problems when using lower boost levels because then it wont realease pressure at all?

So if im running at say 15 psi(which i think im running at now), and i switch out my 1st gen bov for the type rs that is still in the box, then will i have to test the bov so that it works properly at that level?

Oh and also if the bov isnt where you adjust boost level, then where?

 

[tonygst]

Well then im just a idiot cuse i still dont get it.


Oh and also if the bov isnt where you adjust boost level, then where?

I've seen rookies that understand the general concept of a bov better. Let me find a link here quick that will give you a break down of a bov.

 

[No_Skillz]

If the BOV were to control your boost, the system would be horribly inefficient since your turbo would be maxing out the entire time, and boost control is basically dependent on a controlled boost leak.

The basics of a bov is that it holds pressure until you LET OFF THE GAS at which point your throttle body closes, and the bov releases pressure so your turbo isn't boosting into what has effectively turned into a sealed off pipe.

 

[MrBentley]

I've seen rookies that understand the general concept of a bov better. Let me find a link here quick that will give you a break down of a bov.

Okay well let me give you this as straight as possible so you don't get confused...... I AM A TOTAL NEWB WHEN IT COMES TO TURBOED VEHICLES SO DEROGATORY STATEMENTS ARE NOT NEEDED!!

I mean F#$* man... why is it that people need to flame everyone who doesn't know as much about this?

(BTW, i have asked how a BOV works so many times and also about boost pressure so many times and gotten no answers that it aint even funny. It's like you hate on folks who don't know but then won't even help someone out.)

If the BOV were to control your boost, the system would be horribly inefficient since your turbo would be maxing out the entire time, and boost control is basically dependent on a controlled boost leak.

The basics of a bov is that it holds pressure until you LET OFF THE GAS at which point your throttle body closes, and the bov releases pressure so your turbo isn't boosting into what has effectively turned into a sealed off pipe.

Before this explanation i thought that what happend was that the turbo would spool up and pressurize the whole intake system and the bov is there so that it would keep the boost at a certain pressure level (thats where i got the idea of adjustment when i saw the nut on the BOV) and when you shift, it would let go of all the pressure and then build it up again for the next gear.

And now, finally an explanation i can understand. See what happens when you take the time to put it into a logical form.

 

[blcknspo0ln]

here let me try:

BOV - a blow off valve is activated by VACUUM, not boost pressure. It is also commonly known as a bypass valve, diverter valve, whatever. It releases pressurized air from your intake system AFTER you close the throttle plate (let off the gas), so as to not send the compressed air back INTO your turbo (compressor surge).

If set too hard, it will not open under a small load, hence leading to surge.

if set too soft, it will leak under a larger load.

MBC (manual boost controller) - is essentially a tee.. it is placed in between your BOV > intake manifold line and connects on the opposite end to the wastegate actuator of your turbo. A wastegate actuator is in essence a long rod that opens and closes your wastegate. It has a spring inside that operates under boost. The spring/valve will stay closed until you build enough boost to open/extend the rod. This is how you can maintain ONLY 9-11 psi stock, because once you hit that boost level, the spring will be too weak to hold the wastegate flapper closed, and the excess exhaust gas will through the wastegate hole once the actuator opens

When you install an MBC between that pressure source, you are raising the limit of which the wastegate actuator will open. Really, you are just manipulating when the wastegate will open. "Raising" boost means that you are making your wastegate stay CLOSED longer, so that your motor can build more boost. then, via your MBC (ball and spring, or bleeder), the wastegate actuator will open at your desired boost level.

 

[diamondgst]

Exactly as said above. The BOV keeps pressure from being bleed off untill the point you let off the gas and the throttle plate closes. the boost then has got to go somewhere. So your blow off valves opens at let say 24psi so once 24psi is reached the valve creeps open and bleeds pressure untill its safe to close. If it werent for a BOV the boost would just add up and add up and a pipe or coupling would pop off.

A Manual Boost Controller regulates how much the WG accualtor sees and "tricks" it to thinking its running low boost levels so then when it thinks its only at 11psi it opens the accual wastegate and alows gases to go around the turbo fins instead of thew then therefore not making anymore boost. But really your tricket the amount of boost the WG Accualtor seen by using the MBC and lowering the amount of air pasage thew the MBC

Here is some reading up to do on it...this should REALLY help...

http://auto.howstuffworks.com/turbo.htm
page 6 talks about some usefull stuff for you...but i would read the whole thing if i were you...

 

[No_Skillz]

Okay well let me give you this as straight as possible so you don't get confused...... I AM A TOTAL NEWB WHEN IT COMES TO TURBOED VEHICLES!

We all gotta learn somehow. Have fun with the car and keep the rubber side down.

 

[MrBentley]

Cool, thanks for the help guys.