BOV Before the Intercooler?

[TT_NS]

I heard it would be a better idea to put the BOV on the hot pipe b4 the intercooler so the hot air is released instead of the cold air. what do you guys think

 

[25psilaser]

If you put the blow of valve on the hot side you can get compressor surge because it does not release enough air when ever i hard pipe a car i put it as close to the throttle body as possible so i dont have compressor surge.

 

[myblack98gst]

you completely failed at making a vaild post..


compressor surge is when the air is pushed back onto the compressor wheel slowing it down much faster than normal...

you can place the BOV pretty much where ever you want and get the same results..

typically it is more responsive closer to the turbo

look at the SRT-4 BOV is made onto the turbo, and it caaachoo's at light idle revs

 

[Defiant]

I heard it would be a better idea to put the BOV on the hot pipe b4 the intercooler so the hot air is released instead of the cold air. what do you guys think

I think you'd best reconsider who you hear your myths from. As the DSM blowoff is arranged, it's meant to relieve enough volume that it helps the turbine keep spooling. They were pleased enough with this setup to keep it, unchanged, for fifteen years of production.

 

[JZ 97 SS 1500]

Typically you do want it as close to the compressor cover discharge as possible.

JZ

 

[TT_NS]

I think you'd best reconsider who you hear your myths from. As the DSM blowoff is arranged, it's meant to relieve enough volume that it helps the turbine keep spooling. They were pleased enough with this setup to keep it, unchanged, for fifteen years of production.

the company wont change it to help performance they will do what ever is cheaper and more efficient to build and wuts best for emmisions. but i was thinking that it dont rly matter where u put the BOV because it still dose the same job by releasing the pressure i was thinking that it would be smarter to let out the hot air instdead of the cold air.

 

[99gst_racer]

wuts, rly, instdead

I see not everyone has located that secret button to the left of the 'Submit Reply' button.

i was thinking that it would be smarter to let out the hot air instdead of the cold air.

WTF Explain to me how that would be smarter.

 

[ldstang50]

99gst, your car looks great, i like it better than the purple

As far as the BOV, I would think you would want it before the after the intercooler. Isn't a BOV's job to release compressed air that doesnt' make it into the intake mani before it can come back and back pedal the turbo? I know thats a redundant question.
My question lies in the fact that I have seen people (mostly dsmers) running 2 1g BOVs. One after the intercooler and one before. Whats the benefit of this?

 

[99gst_racer]

99gst, your car looks great, i like it better than the purple

Thanks, but what do you mean by "purple"? , I think you might have me confused with someone else....

My question lies in the fact that I have seen people (mostly dsmers) running 2 1g BOVs. One after the intercooler and one before. Whats the benefit of this?

I'm assuming that the only reason they did this was because they were running high boost and the valve size on the 1G bov was large enough. Instead of going with something like a 50mm Tial, they used (2) 1G bov's as a bandaid....
I couldn't think of any other reasons someone would need to run 2 bov's.....

 

[ldstang50]

Thanks, but what do you mean by "purple"? , I think you might have me confused with someone else....

I guess I do, sorry, I thought you had your car repainted, by bad

I'm assuming that the only reason they did this was because they were running high boost and the valve size on the 1G bov was large enough. Instead of going with something like a 50mm Tial, they used (2) 1G bov's as a bandaid....
I couldn't think of any other reasons someone would need to run 2 bov's.....

Well I've seen two 1 BOV's mounted together with an connecting vacuum line connecting them on the nipples, which I guess 'doubles' the amount of boost they can hold.
I guess this would be a similar set up to the guy that mounts his right after the turbo.

 

[Stapl3]

which I guess 'doubles' the amount of boost they can hold.

They just let off more air. They're only going to hold a certain amount of PSI, no matter how many you have next to eachother.

 

[oldman]

99gst, your car looks great,

Yes Paul, you got a nice little rice rocket there.

 

[iwantawd]

to throw another wrench in this topic, if you're not just mounting the bov flat on the pipe do you want the inlet angled towards the compressor or the throttle body?

and im just curious, who has intake piping larger than 2inches in diameter? i have to look up what the stock size is.

 

[99gst_racer]

Yes Paul, you got a nice little rice rocket there.

Actually, my car has a stock appearance. I'm just going so fast in all the pics that it looks like it has a body kit and custom paint.

ldstang50 - Maybe you were thinking of miteclgst.

and im just curious, who has intake piping larger than 2inches in diameter? i have to look up what the stock size is.

Intake pipe? Yeah, my intake pipe is 3" and my IC piping is all 2.5". What was your question?

 

[tonygst]

Yes Paul, you got a nice little rice rocket there.

I think he was referring to the giant wing on your car. Maybe he thought you were the man responsible for the shuttle launches at NASA. That wing has to go man. Otherwise your car is awesome.

 

[ldstang50]

They just let off more air. They're only going to hold a certain amount of PSI, no matter how many you have next to eachother.

ok, i was under the impression that a reverse vacuum was made by connecting the two thus increasing the holding capacity. Thanks for clearing this up for me

 

[iwantawd]

Intake pipe? Yeah, my intake pipe is 3" and my IC piping is all 2.5". What was your question?

yeah the IC piping is what im talking about. I have yet to take the fluid dynamics class to explain this but a garrett engineer told me to keep the flow inside the piping laminar, not turbulent (mach number below .3). Typically, 2 - 2.75 inches will be good for reasonable street horsepower numbers. Really though, you want to use the largest piping you can easily package.

 

[gixrman]

Wow 17 posts and no one still got it right. The BOV purpose is to vent pressure when the throttle plate closes and the compressor is still producing boost, this cause's a shock wave to travel back towards the compressor wheel which could destroy it if it wasn't for the BOV venting.

The WRX has it mounted on the IC, so yes it can be mounted closer to the compressor outlet. But mounting it on the hot side would probably cause poor performance and 350 degree air would shorten the life of the diaphragm.

 

[HIGHPSI4]

I have mine mounted 12" from the compressor outlet. I like it. It is better to release air that is hot so that it does not add heat to the IC rather than venting cooled air (although it may be very small). Here is my short route set up...you can see the BOV right below the radaitor hose.....

 

[boostedinaz]

Wow this long and no one has the correct answer.

You want the BOV as close to the TB as you can get it. Have you even looked at a real racecar and looked at there placement, they all have it as close to the TB as possible. The reason for this is because the TB is what stops the air from moving or entering the engine. If you are close to the part that starts the pressure wave then you can get rid of it well before it does much at all. If you place it far away, like on the otherside of the intercooler, you have to wait for the air to pile up all the way through the pipping them open the BOV and escape. Not good IMO.

As far as venting hot or cold air, it doesn't matter because it isn't going into the motor anymore.

 

[Spyke169]

http://www.dsmtuners.com/forums/showthread.php?t=137655&highlight=bov+close+throttle+body

hopefully this answers all your questions

 

[HIGHPSI4]

I am not following on that. The differential pressure created in the intake and a signal is sent to the BOV and thus opens it. If you vent right off the compressor then a Shock wave' is not created, the pressure is reduced before it can travel the intake system. This allows pressure in the intake system to be released faster and thus does not load up in the pipes. Thats my cut on it. However, when running a hot wire set up it is good to keep the bov away from the MAF so that it does not create a disturbance in the air stream.

 

[TT_NS]

Wow this long and no one has the correct answer.

You want the BOV as close to the TB as you can get it. Have you even looked at a real racecar and looked at there placement, they all have it as close to the TB as possible. The reason for this is because the TB is what stops the air from moving or entering the engine. If you are close to the part that starts the pressure wave then you can get rid of it well before it does much at all. If you place it far away, like on the otherside of the intercooler, you have to wait for the air to pile up all the way through the pipping them open the BOV and escape. Not good IMO.

As far as venting hot or cold air, it doesn't matter because it isn't going into the motor anymore.

the built up pressure thats there when the butterfly valve closes could push back tords the turbine and make it slow down alot quiker and/or surge and causes the turbo to get alot of shaft play after a while

 

[boostedinaz]

Once the throttle blade is closed it cause a shockwave of air. Were do you want a BOV, right at the start of the wave so it can dispense of it immediately or right by the turbo so the shock wave has to travel toward the thing it is trying to break? I would want it to be away from the turbo so there is absolutely no way it would even get close. Not to mention you are making air travel almost 5 feet in one direction, just to go back another five feet when you go WOT in the next gear.

 

[Defiant]

I think the whole Shuttle program should be scrapped.

Man, you guys can find anything to argue about, and mold and bend physics to match your oddly-crafted concepts.

How long do you figure that BOV is going to be doing anything? Think about it, maybe a quarter-second? Yes, there may be some "perfect" location for it. For a given throttle opening. For a given air density. For a given spool speed. For a given engine load.
The design and function parameters are going to wander so far that it won't matter enough where the valve is mounted.