scoobystue

iTrader: (3)

whats the difference between them and dump valves?? do they do anything apart from blow off what there function on the car or is it just for the noise??

WRX Blues

Dump valves literally 'dump' the 'pssssssshhhhhh' sound out of the bottom of the engine - whereas blow off valves literally 'blow' the 'psssssshhhhhh' sound up and out of the engine through the bonnet scoop.

I stand to be corrected but I believe d/v's only add about 20bhp versus a b/v which makes as much as an additional 30bhp.

Andy McCord

They are the same thing, there are two types of dump valve, a recirculating type and a vent to atmosphere model. They prevent the turbo from stalling by dumping unwanted boost pressure, they add no bhp at all.

Andy

scoobystue

iTrader: (3)

i knew they didnt add bhp i think mr blues was being funny are they worth fitting?? i see that hks blow off valves are £288!!!!!

jaytc2003

iTrader: (1)

They can cause slightly erratic running, and also a slight increase in fuelling as your dumping out air that the maf has sensed for fuelling.

nice noise though

flat4_ire

they are the exact same thing, only yanks/japs call them blow off valves, ive the hks ssqv, great sound

scoobystue

iTrader: (3)

ill have to wait till ive old my other car before i buy one though!