Clutch

[Dennisk]

why some cars when they gear change there is a "sisss" sound? especially WRX . Is it becos of the clutch? my friend told me was compressor clutch....???

[Route]

i believe thats a BOV.

[Dennisk]

BOV?

[Defelio]

Blow Off Valve.

 

Tubro cars have air force into rather then NA which sucks.. So excess need to go somewhere when it's not need (when accelarator off, clutch in,change gear...) So to prevent building up too much pressure within the hose. A BOV is installed to release the excess.. michiam like pots with a hole on the lid.

 

Maybe someone else can explain better. otherwise go www.howstuffswork.com Read.

[Turbonetics]

wat u hear from rex r probably BOV....

though some cars hav those clutch dat can make the sisss sound...

i also duno why....

[Dennisk]

normal car can install?

[Maded]

i tink maybe it's the induction sound... when NA cars with CAI fitted floor throttle, the engine has to suck in a lot of air.. so get the sss sound.

 

But this is when throttle press... BOV activate when throttle released...