Looks like a cheap way of installing a dump valve. Are there any reasons why this is not a good idea?

What pressure do they release at/is any Z dump valve useable like this?

Thinking of doing this myself...

 

i dont think it would fit into a stock car, the fan would be in the way??

 

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It *might* fit in a standard car - but yeah looking at the other pics that car has had an electric fan fitted..

 

Quite a few people do that on NA Z's in the states, and have tried it on TT's too - the TT's usually run a bit hot though, it's hard finding an electric fan with the cfm rating of the crank driven one.

 

A single DV will work, it's more a question of if a single DV can flow enough air through it to release the overpressure when the TB's are closed at XX psi.. And that's a lot harder to answer..

 

A better question - why would you want to, really?

 

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GZ.

I'm getting hard pipes from Smithy and as they would need mountings welding on for a pair of dump valves it's just as easy to weld a pipe between instead.

 

By using only one dump valve it would save a couple of hundred squids I reckon.

 

Also it's a bit different so everyone can stand and scratch their heads looking at it

 

How is the flow rate measured on a D.V then?

What do the big single turbo cars use and is there adjustment on them to release at certain pressures for different cars?

 

dunno, but people use ordinary BOV's on cars running 35psi+, so I wouldnt imagine it being a problem, it obviously works on that guys car??

 

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Flow would be measured in cfm or m^3s, but I doubt anyone quotes it for the DV's And then again, calculating how much pressure you need to dump would be an inhumane task..

 

As to what pressure they release at .. The last DV I looked at was a diaphram one on a R5GTT, but I think the principal is the same..

 

The DV doesn't open under pressure, it opens under vacuum..

 

There is a big spring inside that holds it shut against boost pressure (along with +ve boost pressure being applied via the vacuum hose), when the throttle body shuts the plenum hits vacuum, which pulls the DV open working against it's internal spring, allowing the excess boost trapped before the TB's to be vented..

 

I know some piston type DV's are adjustable (you screw them together to increase the spring loading, therefore the amount of boost they will hold, at the expense of them being less willing to open under vacuum).

 

I seem to remember reading that A'pexi BOV's only held 18psi - so that would be the limit of their spring..

 

Anyway long story short - yes it will work, it's a question of how well..

You're saving £200 so it's a tradeoff really - amount of excess pressure released (therefore less compressor stall up to a point) versus cost..

 

IMHO, E&OE, yada yada.

 

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GZ.

I think I'll stick with 2 of them after all.

Might go for the Turbo XS ones as they are fairly cheap and very loud

 

Red Plenum - looks WÄNK

Radiator - looks WÄNK

ONE dump v - cheap skate WÄNKer

 

blue vacuum tube looks cool though!

 

Chris - in anwser to your question - everything should work as intended (IMO)

 

 

 

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Simon