Sounds like a stupid question.... but
How exactly does a recirculating dump valve work?
As far as I know, it dumps when it gets vacum on the control pipe?
How can I set it to dump when the pressure gets to a certain point? can someone please enlighten me as to there operation so I might set mine up!
Er. everyone else tell me if I'm wrong but I was under the impression that a dump valve's purpose is to prevent stalling of the turbo compressor wheel when you go from an open throttle on boost to a closed throttle. The blower is filling the pipework to the inlet manifold with air at up to 25 psi, depending on application, and when you snap the throttle shut the air pressure has nowhere to go. This air pressure backs up down towards the compressor and tries to stall it, in some high pressure applications it can damage the wheel so I've been told. The dump valve is a spring loaded diaphragm and when excessive boost pressure acts on the diaphragm it opens against the spring pressure and the air escapes past the diaphragm. A recirculating dump valve pipes this excess air back into the inlet side of the turbo so you don't hear it working as much as one that exhausts to atmosphere. I figure you adjust the spring pressure so it blows off at just above max boost pressure.
Let me know lads if I'm talkin bollox, could do with knowing how to setup one myself cos sooty' has an adjustable valve on it instead of the standard one. Do you get an accurate boost gauge and make sure its blowing off no earlier than after max boost is seen??
Ok just found this :
http://www.jekylhyderacing.com/bov.htm
it answers most of my questions.... but now i need to know.... what dump valve to get? any recomendations for a cheap recirculating dump valve? And how do I set it up to dump at a certain pressure, do i just cut the spring?
Sorry bout lots of questions!! --
Simon
some of them have a screw/nut adjusting mech, just un-nip the nut, turn the screw..it adjusts the cut off point etc.
......in the bluecorner , fighting out of japan....
oooh where'd ya get the cool gold spinny azev!
yep the adjusting nut provides more/less tension on the bov spring.
aha.. the one embossed with the site so no git runs off with it :D good advertisin..... i made it using adobe image ready.. and erm.. a solid modelling prog..solidworks. my azevs be bak from welders.. 4 months no less.. jesus wept. i'll be machining them soon and tinging them this here colour=P~Originally Posted by Paul Woods
Last edited by adamh; 06-11-2005 at 18:57.
......in the bluecorner , fighting out of japan....
what dump valve to get? jeez..really wouldn know.. im sure the imoc posse would have a better idea there. re-circ is always the best option unless you have something to control the overfuelling at lift off.
......in the bluecorner , fighting out of japan....
Too late, i've purchased a brand new audi 1.8T bosch recirc dump valve. It doesn't look pretty but it only cost me ?5!!! :). I might change to something a bit snazzier when it all works!
simon did you just buy that off ebay by chance? its just i just bought a brand new audi recirc for a fiver off a guy on ebay for my upcoming TT project.....sounds very similar...
http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWN%3AIT&rd=1
i thought,simple but effective... is it the same one?
yea exactly the same infact!!!
I also paid ?5.50, how spooky is that!!
http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWN%3AIT&rd=1
I figured for the money it'll do the job, they are supposed to be good up to 15psi :D
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