heeman10

Before you start rolling your eyes at another boy racer, I would rather not have any sound from the dump valve, but would like the effect. Chatter sounds great, but I want a good, quiet dump valve for lag-killing when I want it. What options do I have? Zetec Turbo on FRST inlet/ECU

Petrucci

isn't the best choice a dump valve that sends back to air box, as on OEM cossies ?
just wondering, as i'm not expert at all

heeman10

Bailey's DV30 valve is an "upgrade" for Escort and Sierra Cosworths. It's a quiet/silent recirculating valve, but I assumed it carried the expelled air back up to the inlet manifold. Does the Cosworth valve send it back to the airbox then?

Petrucci

erm... i fear i would say something stupid, but i'm pretty sure that OEM one sends back to airbox... anyone to confirm ?

heeman10

The valve appears to have a big outlet rather than a narrow vaccuum hose like most dump valves:


Does that help you get a better idea of how it works?

richm

yeah, that's a Bailey recirculating valve - bottom connection goes to boost hose, side connection returns to airbox, and the small connection on the top is the control pressure from the inlet plenum.
If you have a choice, try and take the boost connection from the cold side of the intercooler to minimise the temperature of air that you are dumping back to the airbox/inlet, otherwise you will be dumping hot air into the inlet which then carries on, pre-heated, into the engine.