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Re: Blow Off Valve
Blow Off Valve, Dump Valve, BOV
-------------------------------------------------------------------------------- Name: BOV Also known as: Blow Off Valve Dump Valve What is it? When you take your foot off the accelerator to change gear or whatever there is suddenly a lot of pressurised air from the turbos that has nowhere to go as the throttle plate is shut. A BOV is a valve that is triggered by the pressure difference in the manifold and gets rid of this excess air. If this didn't happen it would cause the turbos to suddenly stop spinning, which would not only knacker them in short order but mean they had to spin up from a standstill when you got back on the throttle again. There are two types of BOV, one vents the air to the atmosphere (atmospheric) and the other vents it back into the air intake (recirculating). The standard BOV is a recirculating job and is generally regarded to work fine up to around 18psi of boost. After this or when they get a bit old, they have been known to leak. The main reason for changing to an aftermarket one is to make a nice loud whoosh when you back off the throttle as nearly all of them are the atmospheric type. Sometimes it’s out of necessity, such as with a single turbo conversion which removes all the stock BOV plumbing. You can mount them in the same place as the stock one (kits are available to do this for most BOVs), or have a flange welded to a hard pipe somewhere (typically the one that goes into the throttle body, but anywhere between turbo and throttle body is OK). You can also keep the stock one and add an aftermarket one as well. Pros: Makes a cool whoosh noise when you back off the throttle . A well made one can hold more boost than the standard one without leaking. In theory recirculating the hot pre-intercooled air back into the intake like the standard BOV could heat up the intake air whereas venting it does not but this is very unlikely to make any difference in practice. Looks 'bling' under the bonnet. A necessity with a single turbo conversion due to removing all the stock plumbing. Cons: If you have a UK car, an atmospheric BOV can confuse the ECU because they use a MAF airflow sensor which is ahead of the BOV. This sensor registers that a certain amount of air is flowing in, so the ECU reacts accordingly by supplying the correct amount of fuel. That air then gets vented by the BOV, so the engine runs very rich. This creates two problems – one, the car may stall if the throttle doesn’t come back on, two, if the throttle does come back on the ECU is trying to compensate for an over-richness and may lean the mix off to undesirable levels, potentially causing detonation. The j spec cars have a manifold pressure sensor and don't suffer from this problem. -Simon B Attached Thumbnails iata si varianta oficiala este postata de catre IanC "un tatic al tuning-ului"daca pot spune asa,este f cunoscut in`afara`,si daca m-ar prinde cai copii post-urile si le repostez aici probabil `i`ll get banned`pe forumul supra sper ca va ajuta la ceva...:) |
Re: Blow Off Valve
o intrebare si o mica precizare.....nu am stat sa urmaresc topicul....dar va intreb ceva si daca a mai fost pusa aceasta intrebare imi cer scuze......Unde ma pot duce sa montez si eu un BOV p un Seat Leon 1.9tdi????
Multumesc si scuze daca am repetat intrebarea!!! Respect!!!! |
Re: Blow Off Valve
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Re: Blow Off Valve
proprietarul vrea doar sa se auda....si oricum...leonul este masina de plimbarica.......
P.S viorele mai intra si pe mess tata! |
Re: Blow Off Valve
nu mi-as keltui banii pe bov la un diesel, iar pe masina mea l-am pus kiar eu:)
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Ai turbat sau inca ma mai ameninti din taste? Blow off pui ? |
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pai pe tine nici sa te bag in seama nu mai ma chinui :)
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eu o sa ma retrag....:)
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am si eu o intrebare care m-a tot framantat in ultima vreme.
Am un polo gti 1.8T, i-am pus spliter de la forge si nu inteleg de ce nu se aude asa tare. Azi am recurs la o metoda mai neortodoxa si am scos tot ce insemna izolarea fonica de pe capota si am inceput sa il aud ceva mai tare decat inainte, insa de afara nu se aude mai nimic. ca si duritate a arcului e setat undeva la mijloc. cum e mai bine in asa fel incat sa nici nu afecteze dand drumul la prea mult aer afara. sa il setez pe o duritate mai mare, sau sa il las mai moale ? am un vecin cu un a4 1.8T cabrio care are bov pe el si se aude foarte foarte tare si nu inteleg de ce pt ca omu nu are nimic modificat la motor. singura explicatie pe care mi-am dat-o a fost ca nu as avea destula presiune in turbo. are cineva ceva idei cum pot sa il fac sa se auda mai tare ? |
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Schimbarea arcului nu face decat sa schimbe presiunea la care lucreaza BOV-ul si poate durata sunetului ( iti inchide mai repede). E posibil ca vecinul tau sa aibe alt cod motor si sa lucreze cu alta presiune in turbina din fabrica. :) Motorul tau e mai nou ca design si s-ar putea sa fie mai eficient ( fara sa vorbim despre posibilitatea ca vecinul sa aiba 1.8T de 180cp). |
Re: Blow Off Valve
se poate ca dupa resoftare, prin marirea presiunii la turbo sa se auda mai tare ? cat despre pierderea aerului, am incercat sa o setez 100% pe atmosferic si nu aveam nici o eroare in bord, insa din ce stiu nu e chiar sanatos pt motor si poate mari lagul la motor.
chestia cu softu cu presiune mai mare la turbo e singura rezolvare pe care o vad. |
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scuza-ma nu am urmarit topic-ul ,dar ce fel BOV folosesti?conectarile sunt DIY sau sunt specifice modelului tau?
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splitter valve de la forge facut special pt 1.8 T. conectarile sunt facute asa cum trebuie.
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Re: Blow Off Valve
sigur mergi cu o presiune mai mare de 0.5 bar chiar si stock fiind masina ta.
la mine la 0.5 bar se aude destul de puternic ... deci nu e vorba de lipsa de presiune la tine. |
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