Fiesta st180 dump valve
Posted: Thu Sep 12, 2013 9:01 am
Hi guys, anybody looked at fitting a dump valve to their st180? If so any links? Cheers
I dont think that any company has specifically produced one yet...
Most of the people that fit them do so because of the noise - they want their road-going boy racer Subaroo etc to sound like a rally car
They were originally fitted to race/ wally cars to improve throttle response after a gearchange, because of the air "hitting" the throttle butterflie/s the air flow can "stall" and "bounce back" even causing the compressor to "flutter"/ slow down
With the dump valve (properly fitted/ set up) on a gearchange when the butterflie/s close instead of the air in the boost pipes "stopping" it gets "dumped" out of the dump valve so the momentum of the air continues to flow and the compressor continues to spin, so when the throttle is opened again (after a gearchange) more boost is available sooner (less lag) - this only applies to turbo cars with throttle butterflies - ie petrol turbo
Modern turbo engines have sophisticated systems under the control of the ECU, some of these "recirculate" the boost so it is not wasted (better for economy) or the dump valve is internal and quiet