1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Hybrid blow-off valves

Discussion in 'A3/S3 Forum (8L Chassis)' started by chief, Dec 17, 2003.

  1. chief
    Offline

    chief New Member

    Joined:
    Dec 17, 2003
    Messages:
    8
    Likes Received:
    0
    Hi, a new A3 t owner here;
    Would someone please advise where in the uk I can get a hybid valve as described below please, I found this info on http://www.amtuning.com.au/
    GO FAST BITS Hybrid blow-off valves overcome the problem by venting most of the non-required intake pressure into the atmosphere, while a small portion is vented back to the turbo and airflow meter-enough to stop problems such as excessive fuel use, backfiring and engine shudder at half acceleration (experienced with purely venting-to-atmosphere valves).

    Cheers guys
    #1
  2. AlexStanley
    Offline

    AlexStanley Member

    Joined:
    Jan 3, 2003
    Messages:
    621
    Likes Received:
    0
    I'm not an expert when it comes to these things, but I think that's what we have on the 1.8t already...
    #2
  3. marksyms
    Offline

    marksyms Member

    Joined:
    Jul 2, 2003
    Messages:
    33
    Likes Received:
    0
    Actually I think the OEM one is entirely closed loop isn't it? i.e. non of the pressure is vented to atmosphere and it all runs back into the intake which is why it's called a diverter valve not a dump valve which is what Scoobys have.
    #3
  4. RichA3Turbo
    Offline

    RichA3Turbo ...Watching you! Staff Member Moderator

    Joined:
    Jan 6, 2003
    Messages:
    5,089
    Likes Received:
    0
    [ QUOTE ]
    Alex Stanley said:
    I'm not an expert when it comes to these things, but I think that's what we have on the 1.8t already...

    [/ QUOTE ]

    Well not quite. 1.8T have a Diverter valve so that all the air gets re-circulated back through the intake into the turbo. Problem with BOV's is that they vent all air to atmosphere an the ECU then chucks a wobbly cos the air that is supposed to be there, isnt! Now with a hybri valve, a little air is vented and a little diverted so you get the BOV sound but not the faults. Personally i couldnt stand a loud Whooosh! sound every time i ease off the gas, but with the CAI, it makes a slight noise anyway and vents no air out so its all good! If its just for the sound, change the airbox for a carbon box and hi-flow oil-free filter.

    Rich
    #4
  5. AlexStanley
    Offline

    AlexStanley Member

    Joined:
    Jan 3, 2003
    Messages:
    621
    Likes Received:
    0
    You live and learn /ubbthreads/images/graemlins/grin.gif
    #5
  6. chief
    Offline

    chief New Member

    Joined:
    Dec 17, 2003
    Messages:
    8
    Likes Received:
    0
    Thanks for the info guys, however I would really like a hybrid, any UK suppiers ???
    :)
    #6
  7. Stuart_A3_Turbo
    Offline

    Stuart_A3_Turbo Member

    Joined:
    Jun 28, 2003
    Messages:
    305
    Likes Received:
    0
    Right.........

    Here we go. Without a doubt, closed loop dv's are the best for performance but im guessing you want the sound of an atmospheric one. Well, hybrid dump valves do this but ive heard many bad things about them. You will also find they are a lot more expensive, or poor quality. I, myself, have a bailey dump valve, venting all the air to atmosphere and experience no problems at all. I do get the odd bit of popping from the exhaust but thats only a small bit of unburnt fuel igniting on the hot exhaust. For me the only option is a full recirc or a proper vent to atmosphere, i wouldnt touch a hybrid valve. If you insist on it then try Impossible performance. They are based in rochester and do a lot of VAG stuff.
    #7
  8. chief
    Offline

    chief New Member

    Joined:
    Dec 17, 2003
    Messages:
    8
    Likes Received:
    0
    Cheers Stuart,
    You are right I do like sound, so it sounds like an Atmospheric one will be better.
    Is the Bailey dump valve a good choice? Or have you come across better?

    Thanks for the help so far ;-)
    #8
  9. Stuart_A3_Turbo
    Offline

    Stuart_A3_Turbo Member

    Joined:
    Jun 28, 2003
    Messages:
    305
    Likes Received:
    0
    Right, bailey one is good and i have tried 2 atmospheric dv's. I tried the turbo XS one from impossible performance and got nothing but problems with it backfiring and not dumping below 4000 rpm. I phoned bailey motorsport and they assured me that they had no problems with their one. What they have done is moved the DV to the cold side, put it on the pipe running from the throttle body to the intercooler. This requires a fitting kit however if you dont want to cut this pipe, i believe a company called SFS will make a one off pipe to fit there with the necessary pipe off it to fit the DV.
    #9
  10. Stuart_A3_Turbo
    Offline

    Stuart_A3_Turbo Member

    Joined:
    Jun 28, 2003
    Messages:
    305
    Likes Received:
    0
    THe best thing to do is to call bailey motorsport on 01763 246660 and speak to them. When i called them they were extremely helpful and spent ages on the phone answering every enquiry i had. Cant fault their service one bit and i had the kit within 2 days. It comes with everything you need including all the blanking plugs to block the original holes off in order to move it to the intercooler pipe.
    #10
  11. Grant
    Offline

    Grant Active Member

    Joined:
    Dec 4, 2003
    Messages:
    1,134
    Likes Received:
    8
    AmD informed me that everytime an atmospheric dv vents by going "whoosh... pssst" you lose about 7 bhp, because you are losing a lot of the boost pressure. You therefore have to build up the boost all over again. By using a diverter valve you maintain the boost pressure after the gear change and you won't have turbo lag - it'll be pure turbo!

    So it all depends it you want performance or if you want to scare pedestrians from 50 yards.

    Personally I think having an atmospheric dv would get a bit tedious after a while!
    #11
  12. benk
    Offline

    benk Member

    Joined:
    Aug 14, 2003
    Messages:
    469
    Likes Received:
    0
    I noticed yesterday that between gear-changes, I could hear the turbo "twitter" - sounded like a fan slowing from fast to slow. I wasn't revving all that hard, and changes could have been faster, so is would this be the turbo pressure being lost between changes?
    Basically - give it gas up to decent speed, upon pressing clutch, I hear the air-release/fan noise, like pitter-pittter-pittttter.
    #12
  13. chief
    Offline

    chief New Member

    Joined:
    Dec 17, 2003
    Messages:
    8
    Likes Received:
    0
    Cheers guys, still debating options.... I want my cake and be able to eat it :)
    #13
  14. Stuart_A3_Turbo
    Offline

    Stuart_A3_Turbo Member

    Joined:
    Jun 28, 2003
    Messages:
    305
    Likes Received:
    0
    [ QUOTE ]
    Imola S3 said:
    AmD informed me that everytime an atmospheric dv vents by going "whoosh... pssst" you lose about 7 bhp, because you are losing a lot of the boost pressure. You therefore have to build up the boost all over again. By using a diverter valve you maintain the boost pressure after the gear change and you won't have turbo lag - it'll be pure turbo!

    So it all depends it you want performance or if you want to scare pedestrians from 50 yards.

    Personally I think having an atmospheric dv would get a bit tedious after a while!

    [/ QUOTE ]

    SO what AmD are saying is that if i put a recirc DV on my car ill be running 210bhp? I would like to see the data that shows them im losing 7bhp each time i dump because i just cant believe that. All it does is increase the lag a bit more but that wont affect bhp, as you have to build the boost up. If im wrong ill happily admit. If the turbo has no lag then its going to be a smooth kick when it spools up. If it has lag then you get a nice kick when the turbo comes in and the turbo kicks in more fierce and you will feel the power suddenly come in. Thats the way i see it anyway, i may be wrong but the fact i have more power and torque than half of the A3 owners on here, with only an exhaust more than most people, doesnt exactly prove that theory right.

    Chief, good idea, dont rush into things ive had car 8 months and gone through 3 dump valves and 3 induction kits cause i jumped in and didnt look around /ubbthreads/images/graemlins/smile.gif
    #14
  15. Ess_Three
    Offline

    Ess_Three Active Member

    Joined:
    Feb 19, 2001
    Messages:
    5,383
    Likes Received:
    1
    [ QUOTE ]
    Stuart_A3_Turbo said:

    SO what AmD are saying is that if i put a recirc DV on my car ill be running 210bhp? I would like to see the data that shows them im losing 7bhp each time i dump because i just cant believe that. All it does is increase the lag a bit more but that wont affect bhp, as you have to build the boost up. If im wrong ill happily admit.


    [/ QUOTE ]

    I see what AmD say as making perfect sense...
    I'm sorry to break it to you...but increased lag IS BHP loss.

    I'll try to explain:
    If you reach peak revs then dip the clutch, change gear, then clutch out and back on the gas...at this point the engine revs have dropped from point x to point y as you have changed up...at this point your engine is making less power than it was at point x in the lower gear.

    I believe that with an atmospheric dump valve the power at point y is lower (AmD say 7BHP) than it would be in a car with a re-circulating DV as all the pressurised air invertory has been lost from within the system as a result of the ADV letting it go to atmosphere instead of trying to keep it withing the intake system.

    It makes perfect sense to me...you are having to do more work to get the inlet system filled up to the required boost level before you can start using the boost to make power...this delay equates to about 7BHP according to AmD.

    The trouble is, that with an atmospheric DV the car may 'feel' faster as you are getting a little lag and then a mighty rush of boost...instead of a more progressive application of power.

    The bottom line is, companies like Audi/VW and Ford (Cosworth) hadn't seen an advantage in power / power delivery / throttle response when developing t6he re-circulating DV, they wouldn't have bothered.

    As the VW advert says...some things are better left alone. The standard DV circuit is one of them in my view....unless you want the signature Subaru type 'pshhht' noise...which I can well do without (I'd rather have the extra few usable BHP thanks)
    #15
  16. Stuart_A3_Turbo
    Offline

    Stuart_A3_Turbo Member

    Joined:
    Jun 28, 2003
    Messages:
    305
    Likes Received:
    0
    Ok then maybe im wrong, makes more sense now you have put it like that but it isnt going to change my mind, im sticking with the atmospheric. If i ever need the power i have a recirc dv sitting here that is easily swapped over anyway.
    #16
  17. TunedS2
    Offline

    TunedS2 New Member

    Joined:
    Dec 18, 2003
    Messages:
    9
    Likes Received:
    0
    /ubbthreads/images/graemlins/laugh.gif We are making BOV-s designed for all 2.2 20VT Audis (S2, S4, S6, RS2). Send a mail if you are interested.
    #17
  18. chief
    Offline

    chief New Member

    Joined:
    Dec 17, 2003
    Messages:
    8
    Likes Received:
    0
    I fully understand your view, but how about throwing this into the fire, AMtuning of Australia have advised that only 40% of the pressure is release using their hybrid, so if AMD are correct, then would that equate to a 2.8bhp lose? If so surely thatÂ’s the best of both worlds????

    Also does anyone use a digital boost gauge? If so any recommendations?

    Thanks again guys
    #18
  19. StephenBogan
    Offline

    StephenBogan Member

    Joined:
    Nov 3, 2003
    Messages:
    253
    Likes Received:
    0
    If the guy wants the noise, he wants the noise. Personnaly, my mates have got Impreza turbos with the said loud dumpvalve, and I think it sounds quality.
    #19
  20. Gambba
    Offline

    Gambba Active Member

    Joined:
    Jan 14, 2003
    Messages:
    1,361
    Likes Received:
    0
    [ QUOTE ]
    ScotSTHREE said:
    Personnaly, my mates have got Impreza turbos with the said loud dumpvalve, and I think it sounds quality.

    [/ QUOTE ]

    Can't disagree there! The phhhsssstttt I get when lifting off just with a CAI induction kit keeps me happy...ish.
    #20

Share This Page