T4 Dump Valve

**scoobysn7x** · Tuesday 16th February 2010, 19:56

I thinking about getting a Dump Valve for my T4 just want some advice, not sure on what type to get is single or twin piston best?, do I need a specific one for the T4 or can I get a universal. And not knowing too much about Dump valves/turbos do I need a blanking plate? and if so why do I need a blanking plate?, just wnating some definative answers as I've looked but cant find them, I've been looking at this dump valve on ebay would it be suitable??

http://cgi.ebay.co.uk/ws/eBayISAPI.d...=STRK:MEWAX:IT

**gmain1967** · Tuesday 16th February 2010, 20:54

Much written about Volvos and dumpvalves...

I was advised not to fit it to my T4 by various persons - I am assuming based on their bad experiences...

I fitted a Forge Motorsport kit FMFK049. This is a twin piston dumpvalve.

I first had the dumpvalve fitted in tandem with the original recirc valve on the turbo (others have done likewise). This way, I found the dumpvalve to be ineffective. I then removed the recirc valve (a pain in the a**e to get the three bolts out), and fitted the blanking plate.

I also cut the vaccum hose to the minimum length, rather than piece it in to the original pipe from the recirc valve.

The dumpvalve itself sits in the boost hose, where it comes from the intercooler, and requires to be rotated forwards, so as not to foul on the bonnet.

Now, contrary to advice and what you may have read elsewhere, I have not suffered from horrendous lag, nor has my MAF been confused by the sudden pressure drop when the unit vents. My car runs absolutely fine. I also run a K and N induction system with a customer air intake and heatshield. Depending on what you believe, this can also give problems with the MAF. Again, I have not had any issues.

That is my experience and I would not say don't do it to anybody. I have not encountered the issues that others mention. My valve was from another forum member and there are others who run them. IMO, Forge would not continue to sell these if there were problems as people wouldn't buy them.

If you are fitting ANY dumpvalve, the key aspect is making sure that the alloy t piece that the valve sits in is correct dia for the boost hose which you have to cut and remove a section from.

Others have also suggested that like a T5, the T4 can run without either the recirc valve, or a dumpvalve, as the boost pressure is, relatively speaking, low, and will not cause damage to the turbo. If you go for this, you remove the recirc valve and fit a blanking plate. Do this, and you will hear wastegate chatter like an old group b rally car....!!!

Hope this helps

**Al115** · Tuesday 16th February 2010, 20:58

I have just taken a rather nice one off my T4, and I have the blanking plate for the turbo as well. PM me if you're looking...

**Al115** · Tuesday 16th February 2010, 21:00

(And by the way, T4s run HIGHER boost than T5s...!)

**scoobysn7x** · Tuesday 16th February 2010, 21:14

Defo interested PM sent, gmain anychance you cna post some engine bay pics up so I can see your set up..

**Al115** · Tuesday 16th February 2010, 21:18

Forgot to say, I've got a hard top intercooler pipe that it fits into as well, so might be quite sorted for you. Will get some pics tomorrow.

**scoobysn7x** · Tuesday 16th February 2010, 21:21

May be interested will have a look at the pics, probably skint after the grille & possibly the dump valve LOL

**gmain1967** · Tuesday 16th February 2010, 21:24

Originally Posted by Al115

(And by the way, T4s run HIGHER boost than T5s...!)

Correct! I questioned that and was advised that same theory still stood as on T5 (boost is not sufficiently high to damage the turbo without excess pressure being removed, or fired back in to the system....)

Personally, I don't think I'll be trying it....

**Al115** · Tuesday 16th February 2010, 21:25

Me neither!

**Al115** · Tuesday 16th February 2010, 21:25

PMed you back. It's amazing how much of this sh*t I have stuffed away in the garage. Hence the "clearout" thread I posted up earlier

**gmain1967** · Tuesday 16th February 2010, 21:26

Originally Posted by scoobysn7x

Defo interested PM sent, gmain anychance you cna post some engine bay pics up so I can see your set up..

I'll get a pic of the valve in situ tomo, but it won't show the blanking plate as that's less accessible than John Terry's mobile phone at present!!!

**Al115** · Tuesday 16th February 2010, 21:28

Originally Posted by scoobysn7x

May be interested will have a look at the pics, probably skint after the grille & possibly the dump valve LOL

You can have the top pipe thrown in, I've got no other use for it and TBH you sound like you'll be needing it

**gmain1967** · Wednesday 17th February 2010, 17:06

Hi

As promised, picture attached. As you can see, valve is rotated forward and downwards. I also trimmed a section out of the rubber seal that runs along the inside of the bonnet, otherwise it rubs on the valve itself.

The blue silicone hose runs from the dumpvalve to the vacuum takeoff in the inlet/throttle body.

If you do fit one, make sure the vacuum hose does not get kinked or split at the metal takeoff from the manifold/throttle body. It exits vertically, and the hose needs to run horizontally to marry up to the dumpvalve.

**Al115** · Wednesday 17th February 2010, 17:13

And here's another one to help you. 1999 T4 with custom i/c (so it looks a bit different, but I'm sure you get the idea):

**scoobysn7x** · Wednesday 17th February 2010, 18:57

Thanks for the picture Gmain, sorry to be a pain any chance you get post a pic showing the other end of the blue pipe coming from the dump valve so I can see where it fits to (thanks)

All115 PM sent

**gmain1967** · Wednesday 17th February 2010, 19:18

I'll take one tomorrow and send on - it's kinda dark out there just now!

It's simple - it's the pipe that will currently run from the recirc valve on the turbo, back into the manifold. It's next to the accelerator linkage.