dump valves

I quite like the dump valve noise. I know I shouldn't, but I just do.

That said, I'm not fussed enough to run it where it may cause problems - which is with most modern engine management systems these days, it seems.
 
I think high performance Jap stuff suits lairy and overkill styling. Supra/Impreza/Evo/MR2T etc, I'm surprised if they don't have a DV.
Non Jap stuff with a DV, just seems a bit wrong imo.
 
Mine VTA's, because one of the previous owners set it that way.

Is it chavvy? Maybe.

Do I like it? It certainly doesn't bother me.

Will I keep it this way? Car works fine with it and it will cost money to change it.

If there's a car that can pull it off, I'd like to think it would be mine ;)
 
I found the car a little more responsive after removing it from my R5GTT, guess it depends on how the car is setup in the first place? I think they're only essential when running serious boost.
 
Worth noting that recirc valves send the heated air thats already been through the turbo, back into the turbo for re-heating- not what you want for a cool air charge. Unless of course you've done a cold side (of the intercooler) conversion.
 
mattyprice4004 said:
*facepalm*

Turbo chatter is when the pressure builds up on closing of the throttle, causing compressor stall.
A recirc valve has similar operation to a dump valve, without the braaaaap. :p
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"Facepalm"

and the noise of the stalled turbo makes/and the wastegate opening comes back through the intake and out of the cone filter, which is why i quoted Joshy and his cone filter sentence.

Which would explain why a friends fiesta turbo made all sorts of weird sounds off throttle without a dump valve.
 
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Turbo stall makes all kinds of weird and wonderful noises. Sorry about the facepalm, it's far too early for me to be sociable. :p

I'd rather have a recirc or dump valve, just to stop turbo stall. I don't like the sound of my turbo being pwnt by a rush of high pressure air. :D
 
I've got a re-circ valve on my Octy RS (Forge 007p). In stock form the valve doesn't make too much noise, just a slight 'ptissssh'. However with a LAN pipe/cone filter the noise is quite a lot more.

A 'dump' valve would throw up loads of engine management codes on the VW 1.8T engine.

I personally like the noise they make and are a usefull tool to scare the crap out of undertaking cyclists :D.
 
i remember about 10 years ago, an evo flying past me and changing gear and the dump valve was more like a very quick,short, screech not more of the typical woosh sound, sounded awesome and did make me jump, kicked out a lot of black smoke though lol
 
Dump valves that dump to air a bit pointless, as dumping back into the intake is a much better idea
 
cm1179 said:
i remember about 10 years ago, an evo flying past me and changing gear and the dump valve was more like a very quick,short, screech not more of the typical woosh sound, sounded awesome and did make me jump, kicked out a lot of black smoke though lol
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HKS SSV (super sequential blow off valve) had one on my RX7 sounded good not as good as chatter tho :p
 
Jamous said:
Worth noting that recirc valves send the heated air thats already been through the turbo, back into the turbo for re-heating- not what you want for a cool air charge.
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Bearing in mind that you are suddenly dumping compressed air into a pipe that is at lower than ambient pressure, and open at one end, you will find that most actually just blows back towards the intake. On standard OEM installs this isn't obvious, but as others have pointed out, a cone or similar will make a fairly loud noise similar to a VTA but lower pitched, as all that air blows back out through the cone.


M
 
I had to replace mine earlier this year as the old bosch one started leaking due to a knackered vacuum hose.

The hose that was there to actuated the dump valve had deteriorated so badly it had come off at the throttle body leaving me with no dump valve. The result was terrible noises (almost like a loud sigh) and a wooing noise on boost after the old valve developed a leak. I replaced the old plastic valve with a forge DV006 recirc valve as it was serviceable.

As for the chatter noises when coming off the throttle without a dumpvalve, it is not the wastegate as this will not be audible through the intake system since the wastegate lives in the exhaust housing. (allows exhaust gasses to bypass the inducer turbine, reducing the turbine speed, and therefore the boost pressure) The only way you can make the wastegate audible is to either fit a screamer pipe or have minimal exhaust silencing. The noises you'll be hearing is the pressurised air forcing the compressor wheel to stop spinning (from over 100krpm) via the vanes. This should result in a pressure spike as the compressor wheel is still spinning at the point you release the throttle. Since the butterfly will be closed the pressurised charge that is in the intake has nowhere to go except back where is came from. (it may result in the wastegate opening due to the increase in pressure on the actuator, but this just allows the exhaust gasses to dodge the inducer) This shock loading on the compressor will lead to bearing damage which in turn will allow excess movement in the shaft eventually allowing the vanes to make contact with the housing and obliterate itself (literally) Cars with no dump valve tend to run very low pressures anyway so it isn't as bad. (circa 0.4 bar)

The chatter noises are usually caused by dump valves that have too stiff a spring in them and are not opening quickly enough to fully fully dump the charge. (a forge valve with a red spring on my car would do this) With the blue spring its fine, but a stiffer spring results in chattering sounds. The open intake results in more of all noises. (induction, turbo spool and boost dumping)
 
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