Dump Valve Problem

Posted By: Anonymous

Dump Valve Problem - 03/06/2008 21:04

Hi there,

Can anyone out there offer some advice?

I have recently installed a FMIC with a size of 450 x 165 x 80mm, using 63mm (2.5") Alloy pipe and silicone hose fittings. After a few wekends worth of work I have finished it this weekend, put her all back together and took her for a test drive. The only change is I have no dump valve noise or very little compared to before with the standard SMIC

Can onyone offer an explanation or solution to this? I would relly like to keep the nice hisssss I had when changing gear.

Hope someone can help, Thenks, Mark.

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 21:13

What dump valve have you got?

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 21:20

Im not sure mate, I've had it off and clened it but theres no markings.

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 21:29

HI there mark. Is it a recirculating one? If so the increased pipe length would probably explain the change in the sound.
http://images.pistonheads.com/aimg/400/400455-6.jpg

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 21:34

When you say re-circ what do you mean? The one I have has a 4mm hose coming off the top, is that a re-circ one?

P.S. How did you know that was my car?

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 22:00

I spoke to you earlier this week $;\)$
The dump to air ones have a valve type thing on the "top" the re-circ have a pipe that feeds the air intake. The standard one is the plastic Bosch with three pipes.
Jack

edit: some one with turbo Knowlage could tell you if a cone type replavement for the air box would restore the noise.

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 22:06

Oh hi mate, So can you sugest anything to get the higher pitched noise back?

Mine must be the re-circ as its got the 4mm hose coming off the top.

Cheers mate.

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 22:10

I think the 4mm hose is the one that tells it that you lifted, but again I don't know for sure.
http://www.bugone.co.uk/fiat/Dump%20Valve/!cid_image001.jpg
is the old standard one. The dump to air ones have a slim pipe also.
http://www.fuelsystem.co.uk/dumpv-c.jpg

edit because i cannot type

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 22:13

cut n paste

Originally Posted By: http://www.gofastbits.com/index.php?parentid=tech_info&option=tech_info

How it works: The usual arrangement is to have the pressure side of the valve attached to the pipe between the turbo and the throttle, and a vacuum hose on the top of the valve hooked up to the inlet manifold after the throttle body. A spring holds the valve shut. When you are on the throttle, the pressure in the turbo piping and the inlet manifold is equal, meaning that the pressure on each side of the valve is the same and therefore cancels itself out, leaving the spring holding the valve shut. When you lift off the throttle, you have high pressure in the turbo piping, and a vacuum in the inlet manifold. The pressure on the bottom of the valve and the vacuum on the top combine to lift the valve open and release the pressure in the turbo piping, since it can no longer go into the engine.

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 22:13

It looks like this one http://www.fuelsystem.co.uk/dumpv-c.jpg

But without the adjustable nuts on top. There is nowhere to adjust at all.

Posted By: Anonymous

Re: Dump Valve Problem - 03/06/2008 22:22

Right, thats a vent to atmosphere.

Re-Circs are nowhere near as loud.

Are you getting a chattering, wooshing or no noise at all after letting off boost.

If the latter what does your boost gauge say your running, pressure-wise?

Posted By: Anonymous

Re: Dump Valve Problem - 04/06/2008 22:03

It sounds like a low pitched woosh.
The boost guage is still reding the same as normal.
About 1.1-1.2 bar on accelleration and vacume when I change gear.

Can this cause any problems to anything?

Cheers mate, Mark.

Posted By: Anonymous

Re: Dump Valve Problem - 04/06/2008 22:09

Nope, id suggest it'd be fine so long as your not hearing turbo surge.

If it was an adjustable DV id suggest making an adjustment or two to sort it out, as much for noise value as well as any performance gains,

Phill

Posted By: Anonymous

Re: Dump Valve Problem - 04/06/2008 22:14

Would sugest buying one that you can adjust so I can get the noise back?
Has this happend due to the sheer volume of pipe work added?

Can you recomend any?

Posted By: Anonymous

Re: Dump Valve Problem - 04/06/2008 22:19

forge do an adjustable dump valve where you tighten or loosen the top to simulate a spring change inside, easy to do and easy to fit too.

Not an amazingly loud DV but does the job, is well built and looks nice in the engine bay.