The next episode in the saga of my oem dumpvalve.

The valve is now making a noise like a big dog makes when it signs "Urrrrr" style whenever the car passes through atmospheric pressure or I lift off slightly within a few psi of atmospheric (0psi gauge).

Is this a nackered diaphragm or has the ghetto fix I applied to the vacuum lines just stopped working effectively?

I think you can inspect the diaphragm if you remove the DV and look from the reverse side?

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement

Correct, the DV diaphragm on my white ST205 completely separated from the plastic housing/flange. Tried glueing it back together but that didn't work either so got a secondhand one instead.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

I have yet to see a diaphragm actually fail

Having revieved a couple of JP's 'sploded stock dump valves both diaphragms have been fine. Unlike the casing of the DV

The diaphragm is a 2(guesstimate)mm thick piece of round rubber. It is sandwidtched between the main body of the dv and the top cap bit that clearly looks separate

In both failures I have seen the actual failure has been the bond between the DV body and the secons glued on bit. This failure is pretty obvious when you look at it

I will need to get some time off in daylight, because I am a touch concerned the noise may be coming from my side of the engine bay and the only vacuum related thing on that side of the bay is the brake servo.

Preliminary tests will be carried out using a 1in piece of dowel to block the chargecooler - dump valve hose, hence disabling the valve to see if its dump valve related or has another cause.

If it is the dump valve I'm just going to plumb in the DV26 off my CS in the short term.

Ive got a spare stocker if you want it??

Postage and a drink voucher???

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1995 ST205

Right, I am now as confused as a baby racoon.

Tonight I removed the chargecooler to dump valve hose and bunged it with 1in diameter section of dowel rod held in place with a hose clip. Then I blocked off the end of the dump valve.

Go for a drive. The "Urrr" is gone. But the t-t-t-t-t noise on gear change is back. The one I described as the valve sounding like it was fluttering. Then give it some beans and sharp lift off, PTSSSSHHHHH.

HOW?! There is no air feed in to or out of the valve. Its just got vac lines attached!

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02 Mini Cooper Race Car
94 ST205 Import
92 ST185 Carlos Sainz
www.mcnab-racing.co.uk

wastegate flutter???

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1995 ST205