Bov location

[slidin40]

Hey guys. I'm pretty sure this has been talked about, but I can't seem to get a straight answer for what I'm looking for. I have a rb20det. I was wanting to know where the "best" location you guys think is for bov? I have a front mount ic, with piping on opposite sides. any advice would help thank you. If there is a forum on here already please point me in the right direction.

[PrimeDirective]

Best location is a couple diameters from the throttle body and recirculated. If figuring out how to recirculate from the other side of the engine bay to the intake is too difficult, you can put the bov on the hot side and it works nearly as good.

The idea is to have the air going through the piping always going the same direction.

[Kingtal0n]

oh here we go.

hot pipe please. as close to the compressor as possible.

[PrimeDirective]

oh here we go.

hot pipe please. as close to the compressor as possible.

Explain your self.

[budderigs]

He is being sarcastic. The point of the bov is to vent the pressure from the intercooler and piping before causing compressor surge.

You want the bov close to the throttle body after the intercooler. Putting it before the intercooler will do next to nothing to stop compressor surge.

Sent from my new phone while on toilet.

[Croustibat]

Any place is ok really, as long as it is recirced ...

[onehundredoctane]

oh here we go.

hot pipe please. as close to the compressor as possible.


This is what Full Race recommended to me when I began my build.

[derass]

Blow-Off Valves | Turbobygarrett (http://turbobygarrett.com/turbobygarrett/blow_off_valves)

"The BOV should be installed between the compressor discharge and the throttle body, preferably downstream of the charge air cooler."

you have a volume of air rushing towards the engine. when the bov is placed near the throttle, it allows that volume of air to be released, the charge air following it will contunue to flow smoothly, uninterupted. this prevents the compressor surge and allows the compressor wheel to remain at a higher speed, giving in turn, better boost response between shifts/opening/closing of throttle.

[slidin40]

Okay thank you. Sorry for being a newb to rb's. So you guys would recommend to keep it here or move it?

[PrimeDirective]

If you are on a stock ECU I would move it back to its stock location on the crossover pipe (which happens to be the best place to put it), and recirculate.

[Corbic]

Delete it. You'll run rich if your still using MAF.

[slidin40]

Yeah I'm still using stock ecu and maf. Thanks. I do plan on doing some ecu work and not sure on the maf. I wish someone would have told me this before I got the flange welded.

[slidin40]

Well kinda suck now I cant use my hks bov. Because I would like my car to run reliable. What would be your suggestions? Just wanting to see what options are out there.

[Jtuned_andy]

It will run fine if its on either side, its just going to run a bit rich with it venting to atmosphere. I have an RB20 and my BOV is on the compressor pipe and same with my SR20. Ever notice how most FMIC & pipe kits for SR have the BOV flange on the hot pipe?

Bov's only purpose is to save the turbo from surge. To do that you need the discharge valve as close to the compressor as possible since every time you let off the gas the throttle plate closes and causes a slight negative pressure that wants to back spin the impellers on the turbo. Having the valve close prevents that.

I could see why you might get a better response with it close to the TB, however then its not doing its job. Dont run a BOV at all, reall turbo surge isnt seen untill certain conditions under high HP are present. That sound when you feather the throttle and your turbo chuffles isnt really 'surge'

[slidin40]

It will run fine if its on either side, its just going to run a bit rich with it venting to atmosphere. I have an RB20 and my BOV is on the compressor pipe and same with my SR20. Ever notice how most FMIC & pipe kits for SR have the BOV flange on the hot pipe?

Bov's only purpose is to save the turbo from surge. To do that you need the discharge valve as close to the compressor as possible since every time you let off the gas the throttle plate closes and causes a slight negative pressure that wants to back spin the impellers on the turbo. Having the valve close prevents that.

I could see why you might get a better response with it close to the TB, however then its not doing its job. Dont run a BOV at all, reall turbo surge isnt seen untill certain conditions under high HP are present. That sound when you feather the throttle and your turbo chuffles isnt really 'surge'

Okay. Now I understand. Thank you for putting that into more detail. So I could put my bov anywhere, or keep factory. Either way it's doing it's job. The only reason why I have the hks on there is because my factory one was taking a crap on me. I was wondering if it was doing it's job just as well where it sits.

[Kingtal0n]

No it will not run fine anywhere you put it.

if you put it near the throttle body response will suffer. The compressor will surge some.

[slidin40]

Okay with that being said. If the bov is installed near the "hot side" where is the best vacuum spot for it? Since the factory spot is a short length. I'm just trying to get all questions answered for future questions by Others.

[Croustibat]

Any place is fine. There may be a slight diff between positions, but you really wont notice it. Kindtal0n is just posting the usual troll stuff based on internet legends; he has never actually experienced the positions himself.

That being said, you may be able to recirc your bov if you wish to keep it. You could also disable it, by adding a metal plate between the bov and the piping flange, or by blocking the pressure reference line that goes to the bov. Either way, the bov wont open; leaking problems solved.

[cotbu]

No it will not run fine anywhere you put it.

if you put it near the throttle body response will suffer. The compressor will surge some.

Why do you keep saying shit like this, just curious. I mean you say it like it's a fact. Young impressionable minds are listening. At least encourage them to find the solution that works best for them.

[SLiDe_WaYz]

You can put it anywhere. But it runs best like this.

If using a MAF, then you should put it on your hot side (turbo side).

If your using a MAP sensor, then you can pretty much put it anywhere you like. Ive heard some get better response with it by the TB, that isn't a proven fact tho.

But if you are using a MAF, and you put it on your cold side you will get mild compression surge nothing serious unless your driving under high boost.

[cotbu]

Turbo XS type H-34 on cold side NO flutter/ Compressor surge!

I got tired of the loud sound, so I recirculated it! Substituted BOV noise for Wastegate noise. Most stock configs have the bov on the cold side. I'm not totally sure about the s13sr's because the pipes kinda cross, when they connect to the side mount intercooler.
so when I look at the stock intercooler I cant really tell.

[Kingtal0n]

heres a car i demolished. Notice it has 2 blow-off valves. I was testing to see which side it worked better on, and which valve worked better on which side..

http://i9.photobucket.com/albums/a90/kingtal0n/teardown/bumper4.jpg

http://i9.photobucket.com/albums/a90/kingtal0n/teardown/bumper1.jpg

hot side wins.

[PrimeDirective]

So you used two different valves, neither of which are recirculated, and show us a crashed car and says hotside wins with no explanation.
Response of a BOV has a lot to do with the diaphragm, spring settings, and the vacuum line that is activating it. How could you possibly make a legitimate comparison with two different valves that differ in those three key ways?

Give us some facts to back up what you are saying.

Are you just trolling everyone in this thread?

[Kingtal0n]

So you used two different valves, neither of which are recirculated, and show us a crashed car and says hotside wins with no explanation.
Response of a BOV has a lot to do with the diaphragm, spring settings, and the vacuum line that is activating it. How could you possibly make a legitimate comparison with two different valves that differ in those three key ways?

Give us some facts to back up what you are saying.

Are you just trolling everyone in this thread?


Want facts? Do a search. Just by appearing in this thread I have spoon fed enough. This is, and I am not joking, the 100th time this question has been answered on this forum.
Hell, search my name if you want. My name alone will hit at least 5 threads in which scientific explanations are given for why the bypass valve needs to be close to the compressor.

[Mikester]

heres a car i demolished. Notice it has 2 blow-off valves. I was testing to see which side it worked better on, when a telephone pole suddenly jumped out in front of me...


http://www.zeroyon.com/public/style_emoticons/default/loser.gif


//////////////////////////////////////////////////////////////////

But seriously, BOV location is not incredibly important for lightly modded cars (which many on here have); so long as it functions as intended. Moving it to the cold side like the S15 has the advantage of the air blowing off/recirculating as close to the TB as possible; which in theory makes sense. But again, runnin it on the hot side in most cases is just as effective.

[Kingtal0n]

But seriously, BOV location is not incredibly important for lightly modded cars (which many on here have); so long as it functions as intended. Moving it to the cold side like the S15 has the advantage of the air blowing off/recirculating as close to the TB as possible; which in theory makes sense. But again, runnin it on the hot side in most cases is just as effective.

An S15? You mean this car
http://i23.photobucket.com/albums/b378/draglarry/S15-10-20-07/P1050424.jpg
http://i23.photobucket.com/albums/b378/draglarry/S15-10-20-07/P1050406.jpg
http://i23.photobucket.com/albums/b378/draglarry/S15-10-20-07/P1050405.jpg
http://i23.photobucket.com/albums/b378/draglarry/S15-10-20-07/P1050404.jpg

And I suggest you inspect the engine bay picture very carefully young one

[cotbu]

If you have access to this vehicle get better photos of this location. Looks like a recirculation valve to me but.....

Sent from my SGH-T999 using Xparent Red Tapatalk 2

http://www.jrautoparts.com/images/nissanclip/s14%20clip2.JPG

[Kingtal0n]

Let me ask this, how many liters of air does the OEM plumbing hold?

As you increase intercooler volume to infinity, the amount of time required to produce a pressure drop on the cold side increases. The compressor spends more time waiting.

[PrimeDirective]

If you're making the claim, the burden of proof is on you. Since you're being an ass, I read the thread where you typed a novel about air molecules in a tire. Someone then found a garret paper that had one bullet point that said for a MAF car a recirc valve is recommended and to put it as close to the compressor as possible.

Side note: This is the second time the OP posted this exact same question. WTF bro.

The following applies ONLY to a recirculated by pass valve.

With the recirc valve on the hot side you MAY see a faster response in spool time because there is a higher pressure in the hot pipe when compared to the cold pipe due to the pressure losses in the piping and the intercooler. This greater pressure difference would cause the air to move into the turbo inlet faster.

The less pressure drop you have through the piping and intercooler the more this becomes a mute point. You also have the disadvantage of the air changing directions at the throttle body.

Nissan puts their recirc valves on the cold side on S14 and S15 SR20 and RB20/25/26 engines (some which eventually came factory with Garrett turbos) which is more complicated to do (for recirc piping) compared to the hot pipe location. I bet they did this for shits and giggles. I would bet that through R&D Nissan determined the air changing directions at the throttle body was a bigger disadvantage than whatever advantages the hotpipe location has.

[PrimeDirective]

^ That plastic tube in front of the valve cover, is the recirc tube that is coming from the recirc valve on the COLD SIDE.

[cotbu]

Yeah, those damn nissan engineers never get it right, if they would've gotten it right the first time... I wouldn't have had to swap an sr20 into my 240sx. And I'm constantly fixing there screw ups. :iwebsarcasm:

[Mikester]

http://www.zeroyon.com/public/style_emoticons/default/fail-1.gif

http://www.zeroyon.com/public/style_emoticons/default/unsuccessful_troll.jpg



BTW, I'm 41 and maybe, just MAYBE I may know a thing or two- So please feel free to go play yourself a nice game of Hide and go fuck yourself... Young one http://www.zeroyon.com/public/style_emoticons/default/glare.gif

[Kingtal0n]

You dont actually count the side mount as an intercooler, do you?

There is no "cold side" on an S15 OEM setup. Yall are drunk if you think that plastic plumbing is cold.

[PrimeDirective]

You dont actually count the side mount as an intercooler, do you?

There is no "cold side" on an S15 OEM setup. Yall are drunk if you think that plastic plumbing is cold.

:facepalm: LOL what. It's okay, you can admit you're wrong. My previous post's point still stands.

The GTR has a "real" intercooler that is front mounted and it still has its recirc valves on the cold side. Page EN160 in the R33 All engine manual, check it out.

[Kingtal0n]

For you guys who want hard evidence, i have a friend who took some temps measures. That is on a CA18DET, which produces less heat than an SR20, and the intercooler is nearly the same. turbo is a brand new T25, set at 15psi with supporting mods.

on a 15°C day, temp after turbo is 157°C .

OEM SMIC, IAT is 55°C after a couple of pulls. It gets worse with every pull. He stopped when hitting 75°C. 208HP torque 29mkg.

random ebay FMIC, IAT is 19° after a couple of pulls, and stays there after some more pulls. 222HP torque 31mkg. more torque and power is still there up to redline, while it goes down at 5000rpm on OEM SMIC.

Now, try that on a 30°C day and watch your pistons melt.

OEM SMIC for S13 and S14, is rubbish. It WILL heat soak, even with a stock engine and no mods, as it is made for a standard driving style. Dont use one if you drive your car hard. ever.

that and it gets covered in dirt qui often due to its position and is hard to clean, much harder than any FMIC .


A better intercooler, wether it is SMIC or FMIC, gives more power AND more reliability. I think it is the ONLY part that does that. You really should use one.

crousti says the side mount is not a good intercooler also. hmm what gives?

now I have to find a way to say that the side mount is a great intercooler, while maintaining that the plumbing remains hot on all sides.

[PrimeDirective]

The fuck does that have to do with BOV location? My previous point(s) still stands. So the SMIC is no good, why would nissan still put the recirc valve on the cold side versus the hot?

[Kingtal0n]

they did not put it on the cold side, there is no cold side. Why do you think I mentioned to measure plumbing volume? The bypass valve functions best when there is minimal plumbing volume between the compressor and it self, it has nothing to do with which "side" it is placed.

If I went outside, and removed the side mount from the S15, replacing it with a straight piece of pipe, you would not be able to tell it was gone.

But suddenly, its got no more " hot side"?
Bypass function would be relatively unaffected, since plumbing volume would not change much. If I was to, say, install a much larger intercooler and left everything else the way it was, the bypass would suddenly not work very well.

yet I never moved it from the "side" it was on, and it doesnt just spontaneously stop working. No, what happened is, plumbing volume changed dramatically.

[PrimeDirective]

Yes, there is a cold side. Nissan put a intercooler there so its at least meant to be a cold side sometimes.

And I think everyone here knows how easy it is to plumb recirc tubing from the hotside of a SR20 and RB20/25/26 compared to the cold side. The S13 SR20 had the recirc valve on the hotside and then Nissan moved it to the coldside or closer to the throttle body on the S14 and S15!

When I say cold side I mean close to the throttle body.

Anyways, believe what you want.

[Croustibat]

Want facts? Do a search. Just by appearing in this thread I have spoon fed enough. This is, and I am not joking, the 100th time this question has been answered on this forum.
Hell, search my name if you want. My name alone will hit at least 5 threads in which scientific explanations are given for why the bypass valve needs to be close to the compressor.

Your nickname appears mostly associated with the stupidest answers, and that is true since your very first post. To the point i really am wondering if it really is stupidity.

Either way you get a master trolling award. Congrats, i could not do it that well even if i wanted, you are in a class of your own :Ownedd:

[slidin40]

I'm sorry I dont realize I asked the same question months ago. I guess I never got a straight answer, so i decided to ask again. But I do thank you for your inputs and advice.

[Croustibat]

The fuck does that have to do with BOV location? My previous point(s) still stands. So the SMIC is no good, why would nissan still put the recirc valve on the cold side versus the hot?

I think they mostly put it where they could. Considering the effect it has...


Mine is recirced on the hot side. Why ? Because i had a bov flange welded there, and it was the simplest and cheapest to do :D

http://imageshack.us/a/img72/4219/20121129194755.jpg


I do not believe the (maybe) 0.00000001ms i lose or win by putting it there makes a difference, really.

[PrimeDirective]

^ I agree, my car is the same way, because the plumbing was a nightmare. However, if a person asks where we can at least tell them what would be ideal and why.

[slidin40]

Didn't* autocorrect

[codyace]

Put it in the easiest spot to recirculate. There isn't anyway for anyone to definitly or repeatably measure the best spot on these cars. Not a a single street car here will know or act any differently.

Again, put it where re circulation is easiest to route.

[Croustibat]

^ I agree, my car is the same way, because the plumbing was a nightmare. However, if a person asks where we can at least tell them what would be ideal and why.

The thing is no one here knows that for sure.

Put it in the easiest spot to recirculate. There isn't anyway for anyone to definitly or repeatably measure the best spot on these cars. Not a a single street car here will know or act any differently.

Again, put it where re circulation is easiest to route.

That, exactly. Maybe a drag car or something with tons of boost ...

[AdamR]

Why do you keep saying shit like this, just curious. I mean you say it like it's a fact. Young impressionable minds are listening. At least encourage them to find the solution that works best for them.

Look at his posts. I think he really loves misinforming with all the pseudo-intellectual nonsense.

[AdamR]

they did not put it on the cold side, there is no cold side. Why do you think I mentioned to measure plumbing volume? The bypass valve functions best when there is minimal plumbing volume between the compressor and it self, it has nothing to do with which "side" it is placed.

If I went outside, and removed the side mount from the S15, replacing it with a straight piece of pipe, you would not be able to tell it was gone.

But suddenly, its got no more " hot side"?
Bypass function would be relatively unaffected, since plumbing volume would not change much. If I was to, say, install a much larger intercooler and left everything else the way it was, the bypass would suddenly not work very well.

yet I never moved it from the "side" it was on, and it doesnt just spontaneously stop working. No, what happened is, plumbing volume changed dramatically.
I am interested in why you think volume of piping on either side of the intercooler matters.