Testing OEM dump valve
 

Can a standard dump valve be tested by pushing the valve open, sticking your finger over the vacuum connector and seeing if the valve stays open? I've tried that on mine and there seems to be very little vacuum there at all - i.e. the valve just pops back down again.

I would guess that it would have to be tested in the closed position for any gas leakage, and at what pressure the spring compresses to release the pressure. Like I say, I am making an educated guess. Will look forward to any other post's..

Dan..

Best way to check if its staying open is to get under the bonnet of the missus motor on tickover & tee off 1 of the vacuum pipes onto the DV while its in you hand....... Then just reconect the pipe b4 she see's ya.

LOL that sounds like it's from personal experience.

if there is boost on the vac side, surely it would help to hold it in the closed pos and help it retain boost :wonder:

if it doesnt work, you would surely hear 'wastegate chatter' (the turbo stalling)

I dunno, 'I'm just a girl' :lol1:

Is there any way to check the standard recirculating valve and is there any benefit from fitting a aftermarket recirculating valve such as forge or gfb , car is remapped running 1.4 bar boost , and no I'm not after the pfffttt sound every time I change gear :lol1:

Another thread resurrection :D

Yes you can test it with a vacuum pump to check that it opens , but being a sealed unit it's difficult to check anything else.

It's also a diaphragm valve and after high mileage the diaphragm can become damaged/split and leak.

http://www.scoobymods.com/attachment...7&d=1269197746

Full thread here......
http://www.scoobymods.com/showthread...rth-12353.html

With a Forge or GFB, you can get spare parts, change the spring rating and both are (AFAIK) piston type giving better shut off and response.

Article worth reading......
http://www.gfb.com.au/tech/tech-arti...low-off-valves

Any idea what the standard oem valve max pressure is before it starts passing?

Hi thanks for the information I've looked at the gfb Mach 2 recirculating valve as it states 30% quicker boost after gear changes , my car has done 75.000 miles so might go for it , another thread resurrection due to me using the search function :)

if the car is performing to what is expected of it, the DV is probably ok. If the DV is bleeding boost back into the intake, the car will loose available power, the turbo will overwork creating higher charge temps. I know this as it happened to me.
I swapped my OEM valve out for a Turbosmart re-circ dv and the car then ran more boost, 2bar instead of 1.6bar. The car was re-mapped, meth inclusion was increased from 10%to 20%, power increased 40hp, from 380hp to 420hp.
If the valve is going to leak it will be at high boost and I don't know how you would test that. I monitor compressor wheel out temps, normally about 130c on full boost but where running 180c with the faulty valve.
Trev

Thanks Trev , real good advice , thanks I didn't think swapping a standard recirc valve for a aftermarket one would make such a difference ,i have no way of monitoring temps at the moment so I'm going to buy the recirc valve and go from there cheers :)

What turbosmart recirc did you go for? I'm currently running 1.75 bar but after it peaks it drops off so think my oem one is passing.

the OEM valve has to be faulty in the first place, which isn't common. You may well change the DV and find no difference, all that would tell you is the original was doing it's job. I had reason to feel there was something wrong after spending a shed load of money and just not getting good results + the high turbo temps + a comment I learned of at RCM that on occaision the original dv had been known to bleed boost and even then it came as a bit of a shock.
Trev

mines a Turbosmart Plumback Single Port. I've had it for around 4 years now.
It doesn't seem to be available anywhere. There is one on Demon Tweeks which has a universal fitting but not a straight fit as with mine. Dual port which either re-circ or vta are available but pricey.
The Turbosmart has a soft spring which reacts well to equalisation/ changes in pressure eitherside of the valve.
Trev

there is one on Demon Tweeks priced at £292.21 + postage

I'm going to order a turbosmart kompact recurcilating valve but there are a few different sizes . 20mm 25mm or 34mm anyone know what size I need for mine which is a 1997 wrx v4 facelift
Thanks :)

Took my recirc valve off today and measured it , it's a 34mm fitment . while it was off I tested it
https://cimg0.ibsrv.net/gimg/www.sco...533880eb15.png
My oem valve seems to be fine ,I was thinking about buying a turbosmart kompact recirc as the website says it's a improvement over standard with some graphs to show gains on dyno , not sure now as reading on here the best valve available is the one I have :lol1: