Wastegate/recirc valve opening at part throttle?

[Schern]

I seem to have an intermittent issue where something is causing boost to be dumped when using small throttle inputs ie when moving off from a junction or on to a roundabout. I can hear a hissing sound so I assume it's dumping boost for some reason. If I give a bit more throttle whatever is open closes and normal service resumes - any ideas what the cause could be?

Car is an 05 vRS estate - standard map and on original turbo with 150k on the clock. Recirc is an 007P so that should be OK. Holds boost fine.

[Bodge]

Maybe try going back to the standard diaphragm DV and see how it feels in comparison.

 

I never liked my Forge piston DV, so swapped back to standard a few years ago. Never looked back!

 

The aftermarket piston actuators don't perform as well as the standard diaphragm ones, they only look nicer! They have more hysteresis, slower response, more variation (caused by o-ring wear and grease volume), you have to service them regularly and if you don't you run the risk of damaging an o-ring and sending it into the turbo.

 

The only downside of the diaphragm actuator is that it uses a silicone filler in the diaphragm itself, which can become degraded over time by oil vapours in the air that passes through it, causing a split and leak. Obviously that takes quite a few years to occur though and the actuators are relatively cheap if it does ever leak.

 

Anyway, I'm rambling. If the DV doesn't change anything, try cleaning the throttle body and doing a reset it if you can.

[Decender]

When was the last time you serviced your 007? Ive had mine 3 years now and had to service and replace the seals etc twice in that time. I have also replaced the piston itself on 2 seperate occasions due to wear.

 

When I last spoke to Forge, they said they recommend servicing the valve everytime you service the car. Mite also be worth speaking to them about the revised piston they do for the 007. I replaced mine with this item recently and its been a completely different car since.

[Schern]

I haven't serviced it - expected it to be fit and forget to an extent! Will see if I can dig out the OEM unit and see how that goes.

[amusingduck]

Did you figure this out in the end OP?

 

I also have this occasionally, stock map and stock DV setup

[Schern]

I've swapped back to the original valve but I've been doing the rear brakes and wheel bearings so it's been up in the air for a week. Did a quick test drive and didn't have the issue but it kind of comes and goes so needs a few more days driving to establish if it's cured it.

Just out of interest what have people used to attach the vacuum hose? On the Forge I had a jubilee clip but it's not exactly a great fit on the OEM valve!