A Specific Dump Valve Question or 2!

[Bison]

Hi guys,

1)I have bought a turbo xs dump valve and a forge motorsport fitting kit. Now i put the dump valve on the other day without blanking the re-circ or re-routing the recirc piece of vacuum hose to new valve. cos i never had time, just to see if the valve went off, it didn;t so I take it that it's not gonna work until fitted properly with the re-circ blanked off and the vacuum hose to new dump valve?

2)Also my dump valve and fitting kit don't like each other so I had to get some reducers and thing, now my dump valve pretty much sticks out into the middle of the engine and look bloody stupid. I think I might have to get a piece of pipe made and weld the valve in like Bracer did in the pics of his dump valve, now I know a few of you boys might be able to make a piece of pipe up for me so that this is possible. If you can help please let me know!

Bison

[madness]

1 - it is for a car with a maf? it should have worked with or without the blank off. and it will not work when stationary.


2- ring demon tweeks, you can buy a t piece to the diameter of the boost hose. about 20 quid and no hassle.

[fraz13]

The DV should work even with the RV in place but both need vac pipes, if the DV is in place but no vac pipe on the end it wont work, The DV will just not be as loud as it will be dumping in 2 places, Also it needs to be a double/twin piston DV as your car has a MAF Single piston DV's will just make the car cut out

[kdst5]

and it will not work when stationary

Eh mine does :haha: and its a turbo xs DV

[BlackBeast]

A car doesnt create any positive boost pressure when its stationary, so how can it work?

[fraz13]

If a rev my car up when stationary it dumps too so how can it not???

[JUDGENINJA]

yep the Bailey's one dumps when stationary too......

Bison - I just put the Vacuum pipe to the vacuum tree on the throttle body. I've a recirc still in place... I've had no probs and in fact think it's in someways an advantage to leave both on....The whoooosssssshhhhh!!!!! sound is the result and not the reason for fitting DV's....

[MattB]

The whoooosssssshhhhh!!!!! sound is the result and not the reason for fitting DV's....

So what is the reason, given that most on here say there is no performance gain with fitting these?

[JUDGENINJA]

The basic principal is :
When you lift of the throttle the throttle body closes sealing air that is being pumped by the Turbo which is spinning at a silly speed (25000RPM seems to ring a bell). If there is no DV in place the air is held in position thus causing a braking effect to the Turbo spindles. Which :
1. is not good for the turbo's life.
2. Creates Turbo lag. This is due to the braking effect. the turbo then has to reach optimum speed again once you have changed gear.

By fitting a DV it takes an almost immediate reading (difference in air pressure) which causes the Air to escape the system allowing the Turbo to maintain its speed for faster response on gear changes and to reduce wear.

I know that volvo turbos are fitted with a recirculating DV system, but this is a Diaphragm, which is weak and tends to wear out. Cheap Aftermarket DV's are also this type which can last only a month or so before they break.

You can buy aftermarket Piston type Recirculating systems which work in the same way, but should be more reliable than the one Volvo fitted.

So the sound you get is only a result and not the reason........

[pzorb]

Plus you get to add another air leak to an already unrealiable car! Woohoo!
(ok, i'm stirring - sorry :haha:)

[JUDGENINJA]

Your car would be unreliable if it had the stick I gave mine...He he....
Air leak is good. as long as it's sealed when it needs to be.... :haha:

[siamblue]

Plus you get to add another air leak to an already unrealiable car! Woohoo!
(ok, i'm stirring - sorry :haha:)

Well climb under you car o/side and take a peek at your lower intake hose :troutslap

[MattB]

The basic principal is :
When you lift of the throttle the throttle body closes sealing air that is being pumped by the Turbo which is spinning at a silly speed (25000RPM seems to ring a bell). If there is no DV in place the air is held in position thus causing a braking effect to the Turbo spindles. Which :
1. is not good for the turbo's life.
2. Creates Turbo lag. This is due to the braking effect. the turbo then has to reach optimum speed again once you have changed gear.

By fitting a DV it takes an almost immediate reading (difference in air pressure) which causes the Air to escape the system allowing the Turbo to maintain its speed for faster response on gear changes and to reduce wear.

I know that volvo turbos are fitted with a recirculating DV system, but this is a Diaphragm, which is weak and tends to wear out. Cheap Aftermarket DV's are also this type which can last only a month or so before they break.

You can buy aftermarket Piston type Recirculating systems which work in the same way, but should be more reliable than the one Volvo fitted.

So the sound you get is only a result and not the reason........

Thanks Judge... :)