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Old 06-13-2012, 06:26 PM   #501
Muh
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Nice reply amalgrover. To sum it up, running with an aftermarket (unless you has to change ur bpv) aint a good idea. Apparently the hybrid ones are "less" harmful
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Old 06-14-2012, 03:43 PM   #502
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You said it. If you like something on your car don't be worried what anyone else thinks.
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Old 06-28-2012, 09:55 AM   #503
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Ok, so here's a question.

I'm going from MAF to speed density. Is there any benefit to going from 100% recirc to a 100% atmospheric?

I would think that since the intake tube that the air is recirculated into is in vacuum (less than atmospheric pressure) there would be a higher pressure differential across the valve if I recirculate it, thus making the actual 'blowoff' even happen faster. Therefore it may even be worse to go atmospheric. But I don't know any more than that about it or if that even matters.
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Old 07-20-2012, 03:42 PM   #504
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Default "almost all leaked..."

"I was shocked at what I found. Almost all leaked." Which ones didn't leak/worked the best?
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Old 07-20-2012, 04:00 PM   #505
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Quote:
Originally Posted by rburns95 View Post
"I was shocked at what I found. Almost all leaked." Which ones didn't leak/worked the best?
the stock one. depending on the year of your car, the new cheap plastic ones i hear can start to leak on stock turbo setups.
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Old 07-20-2012, 06:07 PM   #506
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Quote:
Originally Posted by rburns95 View Post
"I was shocked at what I found. Almost all leaked." Which ones didn't leak/worked the best?
not even really sure where you are quoting from (at least when i skimmed throught the OP i couldn't find this statement), but he goes over what valves he thinks work the best.

Quote:
Originally Posted by jayman4312 View Post
the stock one. depending on the year of your car, the new cheap plastic ones i hear can start to leak on stock turbo setups.
the stock metal and plastic ones leak on stock turbo setups alot of the time. this is the whole reason people swap to aftermarket or do the bpv mod on the metal ones.
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Old 07-24-2012, 09:58 AM   #507
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Quick question, it may have been covered already...I have a 2008 WRX with a Fast Motor Sports FMIC. It only supports a stock adapter. What kind of BOV should I use? I've heard people say it needs to be 100% recirulating. Is this true? I have a TurboXS RFL BOV, will this work fine if I find the correct adapter? Any help is appreciated, so let me know what you think! Thanks.

-Robert
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Old 07-24-2012, 09:59 AM   #508
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Quote:
Originally Posted by blk2.5gt View Post
Quick question, it may have been covered already...I have a 2008 WRX with a Fast Motor Sports FMIC. It only supports a stock adapter. What kind of BOV should I use? I've heard people say it needs to be 100% recirulating. Is this true? I have a TurboXS RFL BOV, will this work fine if I find the correct adapter? Any help is appreciated, so let me know what you think! Thanks.

-Robert
Stock, if you are making more power than stock, crush it.
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Old 07-24-2012, 10:37 AM   #509
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Quote:
Originally Posted by WRXSteye20008 View Post
Stock, if you are making more power than stock, crush it.
The 2008+ WRX BPV is made of plastic. You cannot crush it.
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Old 07-24-2012, 10:35 PM   #510
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Right now im making 300 awhp on a mustang dyno with a conservative tune...do i need a full recirc? or will a full atmo dump work?
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Old 07-25-2012, 10:57 AM   #511
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^ re-read the OP and it answers that question more than once and explains the answer in full detail
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Old 07-25-2012, 05:04 PM   #512
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Yea, still lost
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Old 07-25-2012, 05:32 PM   #513
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a full recirc valve (either stock or aftermarket), a full atmospheric valve, or a mix of somewhere in between will all work on almost any setup. bov's/bpv's are not selected based on whp, so the whp of your setup is irrelevant.
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Old 07-25-2012, 11:38 PM   #514
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Quote:
Originally Posted by xluben View Post
The 2008+ WRX BPV is made of plastic. You cannot crush it.
Interesting, that sucks.

Quote:
Originally Posted by blk2.5gt View Post
Yea, still lost
I have a feeling you are still going to be lost, I would recommend calling a local tuner and asking them to explain it to you and ask what they recommend. Most avoid aftermarket due to the fact the are more prone to leak than a stock bpv. The metal bpv on the 2005 STI's can be crushed to run up to 30psi and even stock can handle 25psi. How much boost are you running now that you feel you need to switch?
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Old 07-25-2012, 11:40 PM   #515
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If you have to ask, you should run fully recirculating.

VTA and 50/50 can work fine, but they generally need proper setup to work well. If you set them up wrong they will run like crap. Either a lot of flutter/surge, or backfiring and stalling. Sometimes all of the above. On the other hand, recirculating BPV's are pretty self explanatory. Usually you can just bolt them on and never touch them again.
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Old 07-26-2012, 12:06 PM   #516
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Quote:
Originally Posted by WRXSteye20008 View Post
Interesting, that sucks.



I have a feeling you are still going to be lost, I would recommend calling a local tuner and asking them to explain it to you and ask what they recommend. SOME avoid aftermarket due to the fact the are more prone to leak than a stock bpv. The metal bpv on the 2005 STI's can be MODDED to POSSIBLY run up to 30psi and even stock OR CRUSHED can POSSIBLY handle 25psi. WITH EITHER MODDED OR CRUSHED YOU ARE GOING TO PROBABLY SEE LIGHT THROTTLE SURGING. How much boost are you running now that you feel you need to switch?
fixed...let's not spread speculation or opinions as 100% facts...


just fyi, if you are trying to run more boost than the stock spring can hold, you are going to start overcoming the spring pressure, and the valve is going to start leaking in boost. this will mean that to continue to hold boost, you are going to have to increase the wastegate duty cycle. in short, you are going to be working the turbo much harder to try and compensate for the weak valve. now, if your turbo is smaller and not capable of flowing air fast enough to compensate for the leaking valve, you will see this problem occuring fairly easy because you are going to be running the turbo close to the top of its boost range even without the leak...BUT...if your turbo is bigger and capable of flowing much more boost than you are targeting, you may not see anything going on because you may not be targeting boost high enough to get the turbo to the top of its boost range.
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Old 07-26-2012, 01:41 PM   #517
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Gotcha, thanks guys
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Old 07-26-2012, 01:43 PM   #518
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I'm running a VF52 @20 LBS by the way...I think I'll stay with the stocker.
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Old 07-26-2012, 02:00 PM   #519
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Quote:
Originally Posted by Dirty25RS View Post
Ok, so here's a question.

I'm going from MAF to speed density. Is there any benefit to going from 100% recirc to a 100% atmospheric?

I would think that since the intake tube that the air is recirculated into is in vacuum (less than atmospheric pressure) there would be a higher pressure differential across the valve if I recirculate it, thus making the actual 'blowoff' even happen faster. Therefore it may even be worse to go atmospheric. But I don't know any more than that about it or if that even matters.
It won't matter either way. Your logic is sound, but there is only a marginal amount of vac between the filter and turbo.
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Old 07-26-2012, 07:04 PM   #520
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Great read!
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Old 07-27-2012, 11:25 PM   #521
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you saved my butt!!! my wrx was running rich and was putting out rich codes but maf and o2 were fine, car would almost die at idle. anywho, the bov was leaking quite a bit and because of you i fixed it and saved 500 smackarinos
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Old 07-31-2012, 05:01 AM   #522
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Quote:
Originally Posted by mbaker View Post
good stuff!!! this is what i have been told all along from a tuning shop back in maryland. now my question for you is what do you think about turbosmart BOV's? i had one on my old car for a good 20k and it never had any problems.

mike
Sir,

What shop in MD? I am stationed at Andrews. Thanks
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Old 07-31-2012, 02:24 PM   #523
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I feel like after 20 pages davnow has given up on trying. :-D
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Old 07-31-2012, 06:58 PM   #524
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Quote:
Originally Posted by Davenow View Post
OK!

Based on the recent influx of BOV related posts, and the ensuing garbage that many people have posted in reply to these, I have decided to make up a small FAQ to try to squash some of the rumors and just straight up bad information out there.

Yes, Unabomber has an FAQ on this. The fact is that it doesnt "get to the point" fast enough for most people to get the point. This is written more bluntly, addressing some issues head on.
We dont need 329872389472387 bits of data and links to valves. We need misconceptions fixed, and we need people to stop repeating the same bad info over and over. Or at least hopefully slow it down a little bit

First, some vocab, since some dont know what it all means

VTA=Vent to atmosphere
-this is the noisey style that is the most popular. 90% of BOVs out there are fully VTA (meaning they vent 100% into the air)
Recirc
A BOV that dumps the vent back into the intake stream. Before the turbo, after the MAF sensor.
50/50
Vents half into the intake, half to atmosphere. Makes some noise, doesnt swing as rich. Typically these are set up sequentially, so that on light vents, it dumps 100% back into the intake, this is so that at light boost/part throttle you get no rich condition, and no/less noise. At higher boost, the valve opens all the way, and dumps into the intake and atmosphere.

Now lets clear a couple things up. If it seems like I am pro-bov, just read everything. I get to the down sides further down.

1. BOVS make you run rich.
--No they do NOT! Here is why. When you are idling, driving around, and under boost, the BOV is CLOSED just like stock. The only way to be running rich is if the BOV was somehow letting air out post maf, WHILE RUNNING, constantly. The exception to this would be a valve that is leaking REALLY badly, and in a case like this, you will know there is a problem right away anyway, as the car will probably barely run. For it to leak this badly, it would have to be physically damaged or just REALLY f'd up


2. But what about when you shift? Arent you rich then?
--Yes. BUT, you need to understand a couple things.
First-The rich condition is not THAT rich. On most tunes the target A/F under boost is @11.1-1 or so. Say you are at 11.1-1, then you shift and it vents. It will swing rich, typically to around 9.5-1. That is NOT that rich.

Second- The rich condition does not last very long. On a typical datalogger, the rich condition takes up no more than 2 rows. You are rich for well under a second.

3. I heard its bad for my cats!
--Its not great for them, but its not really enough to shorten their lifespan in any meaningful way. Exactly how long are you planning to keep the stock cats or even keep the car anyway? Seriously, there are guys running around with 100k+ on their car, totally stock exh, with a bov. No cat problems. If you have a VTA blow off valve, and you lose a cat, you would have lost it anyway, because either the cat was bad to begin with, or your vehicle has some other issue

4. But people will think I am a ricer!
--Did they pay for your car? Are they making your loan payments? Will them thinking this stop you from getting laid? Exactly, then tell them to die in a fire and enjoy your BOV if that is what you want.
It should be noted however, that if you are the type of person that doesnt like people trying to race them, you may want to stay away from a BOV simply because so many ricers think that everyone with a BOV wants to race.

5. I heard that if I want one, I should do a 50/50 venting BOV.
--These are somewhat pointless. You still get the rich condition, just not quite as badly. However, it isnt that bad anyway to begin with. These are however good for people that want a little noise when they are on it, and little to no noise when they arent on it hard. Dont fool yourself into thinking that you wont run rich (because you wont "run rich" with a fully VTA valve either), you still dump post MAF air when it vents, so you still get a rich spot when it vents.

6. But I need one because I run more boost than stock.
--In most cases this is not true. GENERALLY the stock valve can be trusted till @20PSI. Some leak a little bit after about 18PSI, but 90% hold rock solid till about 22PSI, and 99.99999% hold solid at 20PSI. If you are planning to run more than 24PSI, you may want to consider going aftermarket. Over 26PSI, you need to either mod your BOV, or go aftermarket.

7. So BOVs are fine? I can run one with no real downsides?
--Not always. MOST aftermarket valves leak. A leaking BOV, DOES slow you down, and can over time, damage things. To make matters even worse, 99% of people who buy BOVs, dont know how to, or bother to, take the time to set it up properly. So even if they bought a quality valve, it may be leaking.

8. I have had XXXX brand valve for years, it has never leaked.
--How do you know? By looking at your boost gauge? Looking at the boost levels in your datalog? Niether of those prove that the valve isnt leaking.

9. Ok so how do I set my BOV up, so that it doesnt leak/stands less chance of leaking?
--Read the manual first off. Learn how to adjust it. If it doesnt have a manual, just look at the valve. You can almost aways figure out how to adjust it. Some have screws and such, some use washers under the spring. Others use replacement springs.
Now that you know how to adjust it, here is what you do.
First off, start the car, get out and open the hood. If you can see the piston of the valve (look in the hole it vents out of if its a VTA valve), check to see if it is moving at all at idle, or worse, partially open. You want that piston rock solid not moving at idle.
Now give it a little gas. It shouldnt move when you step on it, and when you lift, it should pull up a bit. Depending how hard you hit the gas, it will either JUST move, or fully open.
If its doing anything but what it should be, adjust it a little tighter.

Now go drive the car

When you shift at light throttle, is it venting? If so, is it a pure straight vent, or do you get a little bit of a "chufchchchc" noise right before it vents? That noise is compressor surge. Which isnt as bad as some people like to think and say. Ideally, you are looking to hear a little surge then a vent. Or no sound at all. Either is ok. Now drive it hard, does it surge a little or just straight vent?
Get out of the car and tighten the valve and drive it again. Repeat this until you get a LOT of surge when you lift under boost. Now start loosening it until you JUST start to hear no almost surge.
What the surge means is that it fought opening just a little bit. If you hear a LITTLE surge just as it begins to vent, that means that the valve is holding itself shut as tightly as it is capable of, without being so tight that it doesnt vent properly.

10. But OMG, compressor surge is horrible for your turbo!!
--Unless its really bad, it really isnt going to kill it. I had a conversation with Corky Bell (Author of MAXIMUM BOOST) during a BBQ at his shop about this exact subject and he assured me that compressor surge was nothing more than a bad sound, and that his early miata turbo kits didnt even use one, and never had problems with losing the turbo. This goes against everything I had previously heard, but as one of the godfathers of turbocharging I am going to take his word for it. This guy knows more about the subject than 90% of nasioc all added together.




Bottom line is this.
If you are wanting to be 100% sure you arent losing any power from it, and you are running under about 22PSI, you are best off sticking with stock. If you REALLY want the sound, then stock with a GOOD valve. You would be suprised at how many big name and very popular valves are junk.

Generally you can trust
TurboXS, APS, Perrin, TIAL (best one out there), the HKS RACE valve (not the SSQV) and a couple others. There is one very popular brand that makes a lot of 50/50 style valves, I am not going to name names, but searching my name and BOVs should bring it up. Its 3 letters and they are known for 50/50 valves.

How do I know this? Like what am I using to base my opinions?
I spent a good long time several years back testing valves. As many as I could get my hands on. Buying, borrowing, trading, you name it. All in all I had easily 30+ valves on my car. Multiple examples of the same valve whenever I could, to help eliminate the chances of getting just an extra bad (or extra good!) valve.
I was shocked at what I found. Almost all leaked.

I would like your opinion on which exact BOV you would put on a 2012 sti? I will only be taking the car to a stage 2 for now. I would like a noisy reliable BOV. I don't mind paying a little more either.

Great advice DAVENOW, I am learning a little bit every day from this bad A$$ forum.

Thanks,
Nathan
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Old 08-06-2012, 05:18 PM   #525
OnlyDan
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thank you for clearing this up, you just proved me right against some of my friends!
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