Should a recirc dump valve ( alloy Forge one for clasic, in the over turbo position ) pass much air back, even on idle?

Just open ended mine from inlet pipe ( blocked inlet pipe hole! ) while running and there is a stream of air blowing into what would be the inlet pipe on tickover. This gets worse when revved, and gushes when throttle released a la dumping air!

Is the dump valve shot?
Can it be repaired - diaphragm, spring ?? Forge don't do set up kits for recird valves ( the 3 spring kits for vta valves )?

If not, any ideas for better sealing recirc dump valve??

Thanks

 

I think it might be F'ed as a dump valva should only dump air when sufficient manifold vacuum has developed in the inlet manifold as whne the throttle is snapped shut.

 

Thought that might be the case.

At idle, the manifold is under vacuum ( 20 mm hg on my gauge ) so the diaphragm is lifted a little in the dump valve, and the slight positive pressure between turbo outlet and throttle butterfly ( remember, the engine idles using air from the ICSV pipe off the inlet before turbo ) can escape.

Driving it like a vent to atmos dump valve ( i.e. the return end left open .. inlet pipe bunged! )I hear an increasing whoosh of lost air until I hit atmos pressure, and over - boost - where i hear no noise until I lift off and then the dump valve works as intended.

It's the passing at idle / of boost / manifold vacuum I need to clarify.

Maybe I can stretch spring or tighten spring ( with a spacer ) to hold down diaphragm a little more...

I'll try it and see, and then get onto forge for help / advice and/or parts!!


Any other good after market dump valves I can consider???
Have to dig out the OEM one ..... see if that does it too.

 

I have not used a forge dump valve before. Is it adjustable? If so you could try increasing the load on the plunger therefore a greater vacuum is required to allow it to vent to almosphere.

 

Nah, it's not adjustable ( would need a washer behind spring to increase pressure on diaphragm, which I intend to try ) and is actually a rubber diaphragm resting on or attached to the plunger IIRC, and as vac sucks on diaphragm this defeats spring pressure so plunger lifts and allows post turbo air to pass .

I think.

I'll add a washer or two to the spring fitting to tighten down tomorrow, and see. Otherwise looks like a new dump valve!

Cheers

 

Could be worth seeing if you can alter the title of this thread to say it is a forge dump valve as then people with the same experience might shed some more light on the matter. Best of luck Steve

 

is your car still running ok with it losing air,is it smooth to drive

 

No, it is rough as a dog on idle and off boost, deffo putting dump valve back into inlet, it passes air when not on boost ...

Washers to try to tighten spring, but will more likely move hose a bit to allow fitment ofthe DV into inlet hose... will all change when FMIC goes on next week!

Still working on inlet for FE turbo in a 90 degree entry turbo ... that's what caused this issue in first place!

 

Same problem as me m8

I did fix it, but then I wasn't dumping enough to allow more fuel for the flamer, so took it apart and low and behold... Lots of flames, but in correct DV activation.

I took the pipe off the top which goes into the engine block top and put my thumb over the pipe to stop the engine from stalling and the DV plunger returned to its normal state

I put abit of throttle on but it won't dump.

I placed the pipe back on the top and it just imediatley sucked up the plunger so the valve was constantly open again.

Has anyone a solution for this yet?? As I said, I did fix it by cleaning it, but it is stuck open all the time again now!

Same forge DV as you for a classic 95 wrx