BOV on a TDI

[GTD.]

I deactivate the dump valve with a dash mounted switch wired in series to the positive side of the vacuum solenoid as 99.9% of the time I don't want particularly want to hear a dump valve going off when I change gear or back of the throttle.

When the vacuum solenoid is turned off the dump valve doesn't open, this is on a 1991 1.6 IDI SB engine running 0.8-1bar boost using a Baileys single piston dump valve.

I think unless your running substantial levels of boost the dump valve wont open without vacuum being applied.

[gigaz2]

the dump valve is a differential device, it opens if the force exerted by the air pressure from the turbo is more than the spring force on the other side.
plus, as the spring is on the same side as the piston that controls the opening of the DV, if that spring is weak enough it doesnt need vacuum, but it works like the BOV. it makes a good swoosh, but its pointless and that can damage   the turbo by overspinning.

my opinion:  dump valves are pointless in a diesel.

[GTD.]

my opinion:  dump valves are pointless in a diesel.

I agree, when I had drilled my airbox and fitted a free flowing air filter, I took my mate out for a spin, he asked me if that sound was the turbo spooling up, then said you should fit a dump valve, there's one in my shed.

 This was an exercise just to see if I could make up a system to actuate a dump valve from scrapyard parts, it has only been activated half a dozen times.

[RabbitJockey]

the dump valve is a differential device, it opens if the force exerted by the air pressure from the turbo is more than the spring force on the other side.
plus, as the spring is on the same side as the piston that controls the opening of the DV, if that spring is weak enough it doesnt need vacuum, but it works like the BOV. it makes a good swoosh, but its pointless and that can damage   the turbo by overspinning.

my opinion:  dump valves are pointless in a diesel.

the dump valve is more safety on the motor, and i can definetly see it over spinning the turbo, but since with a bov you'd be letting off the throttle so it definetly won't over spin it

[gigaz2]

the dump valve is a differential device, it opens if the force exerted by the air pressure from the turbo is more than the spring force on the other side.
plus, as the spring is on the same side as the piston that controls the opening of the DV, if that spring is weak enough it doesnt need vacuum, but it works like the BOV. it makes a good swoosh, but its pointless and that can damage   the turbo by overspinning.

my opinion:  dump valves are pointless in a diesel.

the dump valve is more safety on the motor, and i can definetly see it over spinning the turbo, but since with a bov you'd be letting off the throttle so it definetly won't over spin it

if that spring is weak enough it doesnt need vacuum, but it works like the BOV  
and by BOV I mean that device that keep us from getting more than 0.7~8Bar from stock TDs.  I too agree that mouted properly its a safety device for a gasoline engine.

by the way GTD. that was serious thinking! your solution is really simple!