Blowoff valve

[b]Definitions
[/b]
A compressor bypass valve (CBV), also known as a compressor relief valve or diverter valve, is a vacuum-actuated valve designed to release pressure in the intake system of a turbocharged car when the throttle is lifted or closed. This air pressure is re-circulated back into the non-pressurized end of the intake (before the turbo) but after the mass airflow sensor.
A blowoff valve, (BOV, sometimes hooter valve, not to be confused with a dump valve) performs the same task but releases the air into the atmosphere instead of recirculating it. The blowoff action produces a range of distinctive hissing sounds, depending on the exit design. Some blowoff valves are sold with a trumpet shaped exit that intentionally amplifies the sound. The TurboXS model RFL blow off valve is well known among tuners for this kind of design and some turbocharged vehicle owners may purchase a blowoff valve solely for the auditory effect even when the function is not required by normal engine operation. Motor sports governed by the FIA have made it illegal to vent unmuffled blowoff valves to the atmosphere. In the United States, Australia and parts of Europe cars featuring unmuffled blowoff valves are illegal for street use.[citation needed]
Blowoff valves are used to prevent compressor surge, a phenomenon that readily occurs when lifting off the throttle of an unvented, turbocharged engine. When the throttle plate on a turbocharged engine closes, the high pressure air in the intake system is trapped by the throttle and a pressure wave is forced back into the compressor. The compressor wheel slows rapidly and may even stall, and the driver will notice a fluttering air sound. The rapid slowing or stalling stresses the turbo and imparts severe turbo lag if the driver accelerates immediately after the surge event.

[b]Disadvantages
[/b]
In the case where a mass airflow sensor is used and must be located prior to the blowoff valve, the engine control unit (ECU) will meter out excess fuel because the atmospherically vented air is not subtracted from the intake charge measurements. The engine then briefly operates with a fuel-rich mixture after each valve actuation.
The rich mixing can lead to hesitation or even stalling of the engine when the throttle is closed, a situation that worsens with higher boost pressures. Occasional events of this type may be only a nuisance, but frequent events can eventually foul the spark plugs and destroy the catalytic converter, as the inefficiently combusted fuel produces soot (excess carbon) and unburned fuel in the exhaust flow can produce soot in the converter and drive the converter beyond its normal operating temperature range.
One way to mitigate the problem is to reduce the boost pressure, which reduces the required venting volume and yields less charge overcalculation by the ECU. The air can also be recirculated back into the intake, a typical stock setup for cars with an upstream MAF sensor. The situation can also be corrected by switching the fuel metering system over to a manifold absolute pressure sensor, a conversion that usually requires a compatible aftermarket ECU or piggy-back fuel controller. The MAP sensor monitors the absolute pressure in the manifold at all times and will correctly detect the change that occurs when the valve vents, allowing the ECU to reduce fuel metering accordingly.

[b]Operation[/b]

A blow-off-valve is connected by a vacuum hose to the intake manifold after the throttle plate. When the throttle is closed, manifold vacuum without pressure develops in the intake manifold after the throttle plate and "sucks" the blow off valve open. The excess pressure from the turbocharger is vented into the atmosphere or recirculated into the intake upstream of the compressor inlet.


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to the wastegate and bov.

brg ni memamng penting utk performance sebab nak kluar kan udara panas yg ada ...
nice info bro ...

ada turbo bagus ada brg ni...selamat...heheheh

yg penting mesti ada ...

brulah bole bakar line...huhu

baka jgn x baka ...

kalo nda ni brg tubo cpt rusak...selian bunyinya yg menyengat...buli meminang keta lain...kekekeke

macam mana yang diesel turbo?memang tiada pakai blow off tu....hmmm

dah mimang stendet nda blowoff...sukatan turbo ngan kapasiti injin mimang cun2...kalo ada lebihan angin pun masuk balik kedlm blok...

kalo ndak mo pakai ni tapi tukar pakai bekakuk ble ka???? tune sikit je untuk udara sejuk???

berkakuk mcm mana? masuk pigi blok jua ka balik tu angin?

sub injektor ba...

semenanjung ku tinguk durang kasi direct paip tobo ke throttlebody pastu durang tanam sub injektor dalam 2 biji untuk timbak petrol.. lagi sejuk kan kalu macam tu?? tapi mungkin mesti pakai system la tu kalu ndak mesti banjir minyak tu,,

[quote:4457="Customized"]kalo ndak mo pakai ni tapi tukar pakai bekakuk ble ka???? tune sikit je untuk udara sejuk???[/quote]
[b][i]
bekakuk 2 bukan senapang buatan ka?[/i][/b]

kami panggil sub injektor tu bekakuk.. paam2 la,kami ni setting kampung2 jak...

bukan macam ko,setting pun mahal..

ko len la,setting tempat ah tet..

[b][i]adissssssss.... [/i][/b]

urang kaya..

[b][i]miskin ni....kalo orng kaya suda ako beli gen2...kalo maw taw orng kaya 2 c mami bear...setahun 2 kali tukar kereta....[/i][/b]

bro2 sekalian..
klo turbo diesel bleh pkai ka ini blowoff?
ada kesan sampingan ka?

aq pun xpasti sebenarnya..tp,ada injin turbo diesel yg ble msuk blowoff..ada yg xble..nta injin ko ne ble ka x..ermm..tggu otai jwp la ne..