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.

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PrimeDirective

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

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

derass

Blow-Off Valves | Turbobygarrett

"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?

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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'

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slidin40

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.

__________________
5.3/4l80e/turbo 240sx playthrough:
https://tinyurl.com/turbo240

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

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.

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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.

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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.

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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..





hot side wins.

__________________
5.3/4l80e/turbo 240sx playthrough:
https://tinyurl.com/turbo240

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

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.

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Mikester

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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.

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Kingtal0n

An S15? You mean this car





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

__________________
5.3/4l80e/turbo 240sx playthrough:
https://tinyurl.com/turbo240

cotbu

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

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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.

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__________________
5.3/4l80e/turbo 240sx playthrough:
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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.