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Old 02-15-2010, 04:50 PM   #176
Defiant Autospeed
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Honestly, I would rather see the valve being slightly resistant to opening, than opening too easily.


The TIAL is in most people's opinion the best valve on the market (and I wholeheartedly agree) but it is also a bit more picky when it comes to setting it up properly.


If the valve is fluttering, its opening. Just not a full vent. Thats fine.


If you are getting compressor surge in the turbo, its not opening, or at least not enough.

HOWEVER, a little compressor surge, contrary to what some believe, is FINE. And as I said, I would rather have a little surge at lower boost levels, than a valve that likes to push itself open at higher levels.


Luckily, the TIAL is designed so well, that its VERY tough to have it push open under boost. So you mostly worry about keeping the valve shut at idle instead of keeping it shut under boost. For the most part, TIAL valves JUST DO NOT LEAK under boost.



Do a couple things.


Make sure you KNOW exactly what you are dealing with. Is the noise from the valve or is it the deeper sounding "chuf chuf chuf" coming from the passenger side, of compressor surge?

If its compressor surge, what boost pressures are we talking about where it stops happening? When setting a car up with normal mod levels, I dont worry about anything but extreme compressor surge anywhere below @7psi.

If it IS compressor surge, and its still happening up in the 11-12+ PSI range, then maybe give the 9PSI spring a shot and see how you idle. They arent terribly expensive and are an easy swap.

In the meanwhile, pull your valve off, take it apart and clean it real well, and give it a VERY light lube. Personally I like to use a VERY (and I mean VERY) thin coating of copper anti-seize on the piston ONLY where it contacts the internal sides of the valve (make sure not to get any on the sealing surface of the lower portion of the piston)
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Old 02-15-2010, 05:09 PM   #177
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Compressor surge and valve flutter are two different things. If you have compressor surge, Your turbo is making air the motor cant accept. This backs up and causes the compressor to surge. Lots of people have heard this on STG2 STi setups where during spool you get a flutter.

This has nothing to do with the valve. If the valve is fluttering, Its not adjust correctly, is a POS or has the wrong spring in it.

If you have an adjustable valve, I have a way that I have used to adjust them for years with good success. Drive the car on road or dyno. hold the gas pedal just so the boost gets to 0. This is right where there is no vac and yet no boost. 3rd or 4th is good. Now Snap the throttle closed. If you hear the valve blowing off. Its to light and you need to tighten the preload or change the spring. I like to have the vavle open during some positive boost. 5 psi seems good. After all, We dont need the valve opening if you are not making boost.

Most people and valves are opening up to easy and causing Drivability problems. If the valve is a recirc type, this is not an issue.

Good info Defiant.

C
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Old 02-15-2010, 05:18 PM   #178
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Just to expand on what Clark said in the beginning of the above post...

The surge in this particular situation (or more specifically, the particular surge I am refering to) is caused by the turbo making boost pressure, and the throttle plate closing fully or partially, enough to cause that pressure to "back up" into the compressor housing/wheel, which causes sort of a cavitation for lack of a better way of putting it, which is where the surge noise comes from. I refer to this as compressor surge, because that is how it is commonly refered to in this situation.




I do slightly disagree with his ending statement, as IMO, recirc or not, you want a valve functioning properly. If you have a portion of your system not functioning properly, even a small thing, your system cant work to its full potential, and you are losing something, somewhere, performance wise. Even if small, any loss that can be prevented, should be. Sure, ok its opening and nothing is being released out of the tract, but that air that is passing through it, DOESNT BELONG THERE! And its coming back into the intake stream at the worst possible place, directly in front of the turbo inlet. If I were to design and fabricate an "ideal" recirculation setup, the recirculation hose would enter in front of the manifold, pointing directly back towards the turbo (basically coming in from the front of the engine bay area) It would be more complicated to plumb, and realistically the gains would likely be impossible to even measure, but if that air is going to re-enter the intake tract, I want it doing so as smoothly as possible.

But thats more of a philosophy thing, not a right/wrong thing

Honestly, my opinion is that you may as well just vent the thing to atmosphere if you are changing the valve and dont mind the sound. Buy a quality valve and set it up properly and its not going to have any noticeable (or measureable more importantly) impact on performance.
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Old 02-15-2010, 11:42 PM   #179
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you should write a guide on cleaning bovs with pictures and such so that even the "lightest shade of mechanic" can figure it out. since it seems like a lot of the people that have bovs are the less educated ones to begin with.... just saying.
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Old 02-16-2010, 12:54 AM   #180
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Quote:
Originally Posted by tallterror View Post
you should write a guide on cleaning bovs with pictures and such so that even the "lightest shade of mechanic" can figure it out. since it seems like a lot of the people that have bovs are the less educated ones to begin with.... just saying.

hmm... I HAVE been meaning to pull mine off to clean it lately...

Stay tuned for updates on that, thanks for the great idea!
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Old 03-03-2010, 09:03 AM   #181
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i'm getting a Greddy Type S...didn't see it listed on the "good bov's" list...Is it quality?
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Old 03-05-2010, 01:51 AM   #182
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Ok, I really hate to start the debate back up. I will be as nuetral as possible. I just don't see how in the world anyone would honestly think a VTA valve wouldn't throw fuel trims off. The comment about the rich spike only happening for a short period of time during shifts is indeed accurate. Furthermore, there is no A/F learning going on when the throttle is closed and the car is moving.

However, any time the valve opens and the throttle is not fully closed is a different story and this is usually not just a short period of time. It's almost constantly while cruising around town from stoplight to stoplight. Every time you hear the valve blow off it is dumping excess fuel, and every time it does it in closed loop it will try to make corrections and learn. LTFT will not be accurate with a VTA BOV. That means load calculations will also not be accurate.

It does not necessarily mean it is bad for your car though. You will probably not even get an IAM drop with a conservative tune, and it will not affect open loop fueling at all. But, you might have some drivibility issues and fouled plugs, and your gas mileage will absolutely be affected. But I agree that it sounds really really cool (or "mad tyte yo!" for those who need a translator). The only way I would use a VTA is with a blow through MAF or a speed density tune.

Also, you can hear my stock BPV just fine through my SPT intake, but since this thread is intended for noobs, I must add don't get an intake without a proper tune.
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Old 03-05-2010, 06:18 PM   #183
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The thing is it takes a lot longer than what you are thinking for the ecu to determine that the fuel trim needs adjusting, and even longer for it to begin to adjust, then it adjusts in very small steps.


I dont know what to tell you man, its been logged, and done by so many people. You dont get fouled plugs or any measureable change in MPG when running a properly adjusted vta valve. Im not just thinking out loud here, you cant get around hard facts proven time and time again on multiple cars.


As for your last statement, honestly you shouldnt say that, as its simply not always, in fact, nowadays, not usually, true.

A PROPELY designed intake, does NOT require a tune to operate safely. Most (I say most because there are still offenders) of the intakes on the market today work very well. Again, countless people have datalogged, dyno'd with wideband data and such. Real gains, no AFR problems. Of course this varies here and there, but you certainly cannot make the statement that you shouldnt get an intake without a tune as a blanket statement.

Of course you get MORE from it if you tune for it, but you dont have to by any means (again, on MOST)
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Old 03-05-2010, 11:32 PM   #184
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all you gotta do is tape a glove over the horn to see if your bov leaks, if it fills then its leaking
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Old 03-07-2010, 01:52 PM   #185
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Quote:
Originally Posted by ArmOinAwRx View Post
all you gotta do is tape a glove over the horn to see if your bov leaks, if it fills then its leaking

Gotta have a dyno for that though.
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Old 03-07-2010, 02:40 PM   #186
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I use TurboXS and have full exhaust and Full CAI and inlet piping, plus daily boost is 15lbs and my car runs better then it was stock. +1 on BOV (No just the BOV was not why my car runs better its because I take care of my car)

Last edited by Scout01; 03-07-2010 at 02:45 PM.
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Old 03-07-2010, 06:00 PM   #187
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i can imagine this would take the bov-is-bad-bandwagons a little time to sink into their head
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Old 03-07-2010, 09:10 PM   #188
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Quote:
Originally Posted by Scout01 View Post
I use TurboXS and have full exhaust and Full CAI and inlet piping, plus daily boost is 15lbs and my car runs better then it was stock. +1 on BOV (No just the BOV was not why my car runs better its because I take care of my car)
Great post.......very informative.
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Old 03-13-2010, 12:54 PM   #189
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Very Nice
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Old 03-13-2010, 03:13 PM   #190
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Just wandering around the interweb and stumbled onto this little guy



http://surgeline.cobbtuning.com/bov.php



Does anyone have any experience with this valve? COBB stuff is usually pretty good quality (if not overpriced lol.) Anyway, just wondering if anyone's tried it out.
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Old 03-18-2010, 07:56 PM   #191
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what the word on firge 100% rec. bpv i love mine not issuse at all.
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Old 03-22-2010, 12:25 PM   #192
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Quote:
Originally Posted by Davenow View Post

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.
I was wondering if anyone could tell me the name of this company cuz I tried to search it but couldn't figure it out.
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Old 03-30-2010, 02:28 PM   #193
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Awesome information. I've always been a fan of the sound and probably would have made a horrible decision on purchasing a poorly made valve or tuned it improperly. SO much good information in this here newbie section.
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Old 04-08-2010, 06:32 PM   #194
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There's not much that hasn't been covered in this thread already, so I'll just add one more common misconception that we've been coming across frequently.

NOISE does NOT equal FLOW.

ie. some people seem to think the louder the BOV, the more it flows. That is simply not true. Flow is probably the most important aspect of a BOV, and it's important to ensure your BOV/BPV flows enough, otherwise it won't do its intended job. The noise is simply a by-product of the venting process.
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Old 04-09-2010, 03:45 PM   #195
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I bought a turbosmart dual port second hand with low miles for a great price. Once I adjusted it a bit (like 15 minutes at idle and a few runs across town.) I am very happy with the results. Idle is rock solid, car doesn`t feel any different as far as throttle transitions. I`m running in hybrid mode. Under in town conditions it recirculates mostly internally, but under hard driving it has a nice kick to it venting to atmosphere. I would recommend it to anyone just make sure you adjust it and you should be fine.
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Old 04-10-2010, 12:10 PM   #196
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GREAT INFO. Especially for me. this is my first subaru, and my first car that has a turbo.
Is anyone out there have a 50/50 that they are trying to sell.
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Old 04-11-2010, 01:12 AM   #197
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Quote:
Originally Posted by Psychoreo View Post
Just wandering around the interweb and stumbled onto this little guy



http://surgeline.cobbtuning.com/bov.php



Does anyone have any experience with this valve? COBB stuff is usually pretty good quality (if not overpriced lol.) Anyway, just wondering if anyone's tried it out.
I have never even seen one of these in person, but Cobb is SUPER anal retentive with their testing before they release a product to market, so I would bet on it being a very good valve. But dont hold me to that. It could suck. I doubt it though.
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Old 04-11-2010, 01:15 AM   #198
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Quote:
Originally Posted by turbosmart View Post
There's not much that hasn't been covered in this thread already, so I'll just add one more common misconception that we've been coming across frequently.

NOISE does NOT equal FLOW.

ie. some people seem to think the louder the BOV, the more it flows. That is simply not true. Flow is probably the most important aspect of a BOV, and it's important to ensure your BOV/BPV flows enough, otherwise it won't do its intended job. The noise is simply a by-product of the venting process.
Not just that but noise is more related to the design of the valve, IE the shape of the hole, if there is a trumpet at the hole (like the TXS RFL) or not, that sort of thing.


Thinking about it, I would bet that the best flowing valves, probably sound weird, and arent very loud. Because to flow the most, it has to be a big free flowing passage, which isnt condusive (sp?) to making a lot of noise. I would think that the smaller and tighter the hole, the louder it would be, but that would also cause a big restriction. So its entirely possible that the loudest valves flow the least. (its not like an exh system where bigger=louder)
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Old 04-21-2010, 07:40 PM   #199
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wow to much info!! bov= problems!! keep it stock! they can handle the power if ya know how to drive!
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Old 04-21-2010, 07:59 PM   #200
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Quote:
Originally Posted by scoobyoutback73 View Post
wow to much info!! bov= problems!! keep it stock! they can handle the power if ya know how to drive!

No, no, and no. Did you even read the ****ing thing or just come in to post drivel?
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