dump valve question

**mightywolf** · Saturday 3rd July 2010, 21:22

ok I've got a 98' S70R (auto). It has a dump valve fitted on the pipe near the throttle body at the front of the car. From the dump valve the little pipe comes off to a t-piece. One end of the T pipes to the boost gauge and the other pipe off the T goes to the upper manifold (small nipple directly below another small nipple just next to/under the throttle body.
Now it dumps fine but I noticed today that on the turbo a nipple was showing with nothing on it. I've sussed out that a pipe should go from that nipple on the turbo to the nipple on the manifold where the dump valve now feeds in to? I think.
So the million dollar question is what is the nipple on the turbo? Is it the top of the re-circ valve? If so I know I need to take off the re-circ valve and blank it, but would capping that nipple off be ok in the meantime?
The car boosts at a good 9psi at full welly, but it also hisses from the moment you start accelerating. It sounds like the dump valve, but could it be the re-circ valve? All hoses seem fine with no evidence of any leaks anywhere. Sorry if thats a bit confusing.
Cheers,
Mark.

**claymore** · Saturday 3rd July 2010, 21:25

Your right, it is the recirc valve, you might get away with putting a short length of pipe on it and putting a one way valve on there.

**mightywolf** · Saturday 3rd July 2010, 22:54

so could that be the hissing I'm getting? and what would capping it off do?

**mightywolf** · Sunday 4th July 2010, 17:08

will it lower the possible performance leaving the re-circ on?

**brett craig** · Sunday 4th July 2010, 18:01

needs either capping or blanking, blanking is the correct method

**mightywolf** · Sunday 4th July 2010, 19:25

ok so next question is, if I take the dump valve off (I ain't bothered about it) was size is the intercooler hose its connected to and where could i get another hose?

**brett craig** · Sunday 4th July 2010, 20:10

depends which pipe you have cut into, is it the silicone pipe that has a branch coming off it or is it the hard pipe that runs from the turbo to the throttle body ?