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  #1  
Old 09-15-2004, 02:37 AM
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Exclamation BOV's, DV's and the Audi closed loop turbo system.

The Audi turbo system is a closed loop system by which all unused boost that is spooled during off throttle and gear shifts must be re-routed within the system; it cannot be vented to the atmosphere due to the dependence on the MAF and ECU to properly read and interpret air flow dynamics within the intake tract. Therefore BOV's (Blow-Off Valves) are not used because they create a rich air/fuel condition (i.e. less air to fuel ratio) which will damage the catalytic converter, create soot on the exhaust pipes, and cause occasional misfiring (due to the purged air) which will result in ECU miscalculated timing adjustments and other errors.

For Audi closed loop turbo systems, a BPV (By-Pass Valve) or DV (Diverter Valve) is needed to recirculate the purged air and keep it within the intake tract.

As of July 2004, the following valves were available on the world market:
AmD Viper = Polished chrome version of Bailey DV with AmD logo, $$$ (see "Bailey" below)
Bailey = Probably the most popular, serviceable, $$$
Evolution Motorsports = Cosmetic, 4 color anodized choices, not serviceable, $$
Forge = Large (may have fitment problems), serviceable, $$
Forge 007 "A Line" = Same as standard Forge, flat top for better fitment, seviceable, $$
Forge Race = Larger than others (see above), adjustable, serviceable, $$$
GFB Stealth FX D-BOV* = Exclusive unorthodox design, externally adjustable, tight fitment, not serviceable, $$$$+
HKS SSQV BOV** = Dual stage pull-type relief valve, highly competitive for open loop systems, not for Audi turbo sysytems, $$$+
HKS Racing BOV Type II** = Single stage aluminum pull-type valve, same as SSQV but able to handle up to 43psi (3.0 bar), $$$$+
Hyperboost = Cosmetic package, not serviceable, $$
Hyperboost Adjustable = New, cosmetic package, may not fit S4, adjustable preload, not serviceable, $$$
Hyperboost HX = Newest, very cosmetic package, new internals, not serviceable, $$$
OE Bosch TT 710A = THE STOCK DV FOUND IN ALL (1997 AND UP) AUDI TURBO MODELS, Audi part # 034-145-710A OR 06B-145-710, $
OE Bosch TT 710N = Basic, popular & low-budget upgrade, maintains stock look, not serviceable, Audi part# 06A-145-710-N, $ (some dealers charge more)
OE Bosch Sport 110 = MTM upgrade, same as 710N with "better" internals, not serviceable, $$

$ = under $50 USD
$$ = $50 - $150 USD
$$$ = $150 - $250 USD
$$$$ = Over $250

* The GFB D-BOV is currently an unproven design; it is a hybrid diverter and blow-off valve; it is intended to act as a diverter valve while providing the cosmetic audible benefits of a blow-off valve; it has yet to be determined/proven whether this design is effective for use on the Audi closed loop system or whether it may be causing long term damage.
** The two HKS BOV's are mentioned here because they have shown up on some highly unorthodox applications on the S4; they were not used properly and eventually removed due to poor recirculating feeds and other ecu errors.
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  #2  
Old 08-16-2008, 06:46 PM
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Am I the only one using APR R1 DV's? (not on the list)

http://www.goapr.com/Audi/products/r1.html
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  #3  
Old 11-13-2008, 08:43 PM
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Why do people replace these? Do the stock DV leak under a certain amount of boost. do they stay open not allowing boost to build?
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  #4  
Old 01-20-2009, 07:58 PM
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hi, i am also in need of information on this. what does this do and since i am new to how the internal of a car component works. Could anyone give extra information on this. I got a 2009 A4 B8 1.8T, so i am interested to know all about the extra stuff i can do to my car . thanks
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  #5  
Old 01-28-2009, 03:40 PM
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So, would using the Forge "splitter", DV in combination with BOV, be a bad choice for my 2001 audi TT Quattro 225HP? Or should I just stay with the DV?
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  #6  
Old 02-09-2009, 07:41 PM
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does anyone have any news on the AWE Tuning DV1 DV?i just installed it last week and my car makes a weird kind of like fart noise whenever i let off of the gas or step on it again. any help would be nice
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  #7  
Old 02-10-2009, 10:46 AM
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I got the Forge Motorsport hybrid BOV/DV and since it's fully ajustable, it made a big change on holding up the boost on my car ( 2000 A4 1.8t Q ), before I change it, my car was holding 15 to 18 psi and now it's 20 to 22 psi without any more mods, but as far as long term damage, I got to say '' will see ''... but I don't think anything bad is gonna happen since the Forge hybrid is 75%DV and 25%BOF.

http://www.namotorsports.net/detail....t_cd/FMDVSPLTR
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Last edited by sadik666; 02-10-2009 at 04:51 PM.
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  #8  
Old 02-11-2009, 10:39 AM
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Putting in forge dv's how much does it deaden the psshhh noise? thanks
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  #9  
Old 02-11-2009, 03:38 PM
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if you got a oem air intake you don't hear much but with a short ram intake, you'll hear it don't worry ... I really start hearing the psshh noise when I installed my Carbonio intake ...I start hearing it as low as 5 psi ... and I got Tiptronic tranny and I soon as I lift my foot off the gaz pedal I can hear it ... and it make a great sound to...I will try to put a sound clip ...
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  #10  
Old 03-31-2009, 11:34 PM
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Default bov's on s4

so there is now way to get the PSHHHH sound with out sacrificing drivability? do any chips enable the ability to install blow of valves?

Last edited by nogaroblur; 03-31-2009 at 11:36 PM.
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  #11  
Old 04-16-2009, 04:14 PM
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I'm using the apr r1 , bigred the noise sounds like the dv at 0 psi the diaphram is vibrating open and closed but not sure yet if that is normal
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  #12  
Old 04-16-2009, 04:16 PM
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they get a stuck piston
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  #13  
Old 05-06-2009, 08:13 PM
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i have the gfb hybrid, i love it. Only problem i have is that the spring inside is a little weak and not changable. It basically blows off loud then kinda flutters, but oh well
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  #14  
Old 06-21-2009, 02:06 AM
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can we get a sound file thread going? lets hear your audi bov's
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  #15  
Old 07-09-2009, 03:18 AM
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Well I am about to place an order:
Atmospheric Blow Off spacer for VAG 2.0 FSiT

Feedback on this type of bov please. Thanks
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  #16  
Old 07-20-2009, 03:35 PM
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So what this thread states is no BOV's? but a DV instead. What would be the best one for a B5 A4 1.8T
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  #17  
Old 08-09-2009, 03:58 PM
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Default wait,

what if you are using an aftermarket turbo kit? is all this talk just about putting a bov on your stock audi turbo system?
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  #18  
Old 08-14-2009, 10:57 AM
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Quote:
Originally Posted by bigredB5 View Post
does anyone have any news on the AWE Tuning DV1 DV?i just installed it last week and my car makes a weird kind of like fart noise whenever i let off of the gas or step on it again. any help would be nice
Try reinstalling your DV1 in the "Reversed from OE" orientation. The reversed orientation is actually the proper connection direction for the DVs used on the 1.8T and other VAG cars using a similar setup. Reverse from OE orientation means with the flow of excess boost pressure air into the DV at the bottom center port, connected to the plumbing from the compressor discharge to the intercooler crossover pipe, and the side port connected to the turbo compressor intake pipe.(TIP) The reverse from OE orientation allows for the use of the lightest spring and pre-load, while also providing for the fastest response and leak proof performance of the DV.
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  #19  
Old 02-12-2010, 11:05 PM
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ive heard the forge DV/BOV is pretty good. and ive also heard that the stock audi TT DV is good also. true?
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  #20  
Old 02-17-2010, 01:06 AM
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I ordered the Forge BOV/ DV the other day and recieved it today.. We replaced the factory DV with this one today but didnt get the PSSSH noise I was expecting... We thought maybe we had it on the wrong way so we tried it the other way... Still the same thing nothing changed.... Any suggestions??
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18t, 2004, a4, adjustable, audi, b5, bov, budget, cars, diverter, dv, hks, hybrid, hyperboost, tt, turbo, valve, vs


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