Dumpvalves
Turbo Mini Forums

Wat dumpvalve do u guys think is best overall?

Depends what you define as 'best'.

Loudest, best value, most reliable..........

Basically there are two types, piston and diaphram. I've only ever used a piston type and never had a problem.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

the only thing they do is sound nice if that's what you like, other then that they do nothing we don't have big enough turbos to worry about getting the pressure out when we lift off. if you run a T4 then you do need one to help the turbos life.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

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I wouldn't run any modern type turbos (Gt seires for example) without one TBH!!

The rotating assembly is half the size of the older type turbos (T series), and most modern cars run some kind of dump valve for a reason. Im sure the fact my Dv wasn't working properly had a contribution to the short life of my turbo!

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1/4mile in 13.2sec @ 111 terminal on 15psi

what he said ^^^^^^^

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Mine was definatly making that chirping surge sound when lifting off at 1 bar, sounds like the 6 million dolar man sound when he jumps over stuff.

The seals on the piston types can swell with fuel contamination (the Bailey type for example) causing the piston to stick open and the diaphram types can split. Did anyone ever find a supplyer of the kevlar or whatever diaphrams?

Im sure Ric managed to get hold of a kevlar diaphragm. Can't remember where from but its on another thread somewhere quite recent.

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1/4mile in 13.2sec @ 111 terminal on 15psi

i use a grpA forge one that seems to have been reliable.

demon tweeeks?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I got rid of the dump valve as it irritated me no end hissing and farting every time I lifted off.I now get a loud chirrup every time,nearly as annoying,and I,m only on 8 psi at the moment.Makes the car sound like the rally cars entering a fast corner when I,m still inside the 30 limit.

I dont run a dump valve they do my head in!

Id much rather have the chirrup than the wooooooooooooooooooooooooooooooooooooooooooooooootaaaaaaaaaaaaaaaaaaaaaaaaaaaassssssssssssssssssssssssssshhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.................







ssssssssssshhhhhhhhhhhhh.


But have always been lead to believe the turbo has a shit fit if you leave it like this and run some decent boost through it.

Hmmm, so which causes more problems diaphram or piston? and which have a better sound?

piston i think is better if kept serviced.had one on 200sx.and the chirrup sounds awesome like that alot more.and run that for a while at 15 psi no probsfor ages chekced turbo after ten odd thousand miles and was fine

On 30th Aug, 2008 Richie said:
too much my wife says "not that friggin site again" so i pull my pants back up and turn it over to TM. iam on pretty much every day as i lead a sad existance

I think the fuel contamination is down to being carb fed rather than fuel injected. Some people mount the DV upside down with a 45 degree hose off the plenum and this might help? Don't know, mines on the shelf along with all the other bits.

i ran with a HKS SSQV on my supra, tune-able sound and you can keep the compressor surge at low rpm if ya want (the rally car sound) i got bores and removed the insert..to give a quiet wooshh

imo the ssqv is the best will not leak at any boost level either

Yes i moved to the darkside

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Do you know where to get the viton seals phil?

On 30th Sep, 2008 richminiturbo. said:

On 30th Sep, 2008 Brett said:
i ran with a HKS SSQV on my supra, tune-able sound and you can keep the compressor surge at low rpm if ya want (the rally car sound) i got bores and removed the insert..to give a quiet wooshh

imo the ssqv is the best will not leak at any boost level either

I've never seen these used on mini's i always thought they weren't possible to use!

Yes i moved to the darkside

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The dump valve as most of you know is fitted to relieve the pressure build up seen at the output of the compressor. If this pressure is aloud to build without release it will cause the compressor to slow down and any increase in pressure will cause an increase in temperature. So here the dump valve helps prevent the rotating assembly from stalling.

Second, the turbo unit is what is known as a coupled compressor that is the turbine is directly joined to the compressor. The turbine in The T3 is an inpingement type turbine, that is it works like a water wheel. If the turbine wheel is physicaly slowed and the exhaust gas continues at the same flow rate the kinetic energy in the exhaust gas is adsorbed by the turbine wheel in the form of heat instead of driving the turbine wheel. this is one way in which the life of a turbo can be shortened as prolonged excessive heat soak will be to the detrement of your turbo.

So now you now the basic reasons for fitting a dump valve, if the pressure build up at the compressor is released the compressor speed can be maintained by allowing the turbine to spin it without adsorbing as much energy.

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Hi,
+1 for Forge Group A, with tuning kit and filter
I've got 2 :)
Cheers,
Gavin :)

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My Mini build diary

i had a diaphram DV for some time and never had a problem with it till the diaphram slit. i then got a piston one and it got stuck all the time, standard grease would last the day, copper grease would last about 2 days and silicone grease would last over a week. after the seal failed i fitted some cheap o ring from the car spares shop but fitted the DV with the vac pipe pointing to the ground. never had a problem since and that was about 3 years ago

Ran a Blitz SSDV on my Impreza, never had a problem with it and pretty tempted to get one again for my mini!

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