Hi all could anyone shed some light on why I am getting TURBO CHATTER eventhough I have a forge dump valve, any advice would be greatfull thanks

 

Is the piston stuck in the dump valve or spring set too hard?

 

No the piston is ok. How do you set the spring on a forge !

 

if the spring is not adjustable via a screwed rod at the top of th dv the im afraid u need to strip the dv down and order a milder spring , that is if ur dv is servicable and or if it is adjustable , worst case scenario is that it may be a sealed unit and is not rebuildable or serviceable which means get one that is lol hope this helps mate , it would also help if u posted a pic of the dv

 

U can get new springs from forge
Forge Motorsport | Alloy Fabrication

 

second that you can buy a kit that has loads of different springs in for the forge dv i seen them on the bay today mate

 

nowt wrong with turbo chatter, you can even run it with out any dump/recirc valve if you wish. td05's and vf34 onwards can run valvless, but it will sup more juice in the long run.

 

Forge Motorsport | Alloy Fabrication
FMDVSUB01 - Dump Valve for Subaru Impreza MY 01 onwards.
it similar to this one

 

My car is a 53plate wrx 2.0 turbo by the way. Dont get me wrong the chatter
( squirrel muncher ) is very good, I just wondered why some times it does the pssssssttt and other times it does not cheers

 

if you have been running the valve for some time with no problems it probably just needs a clean. take the allen cat bolts out from the top and get cleaning. brasso on the end or a dremmil polishes it up real nice

 

do you have a induction kit on the car as turbo chatter is actually the turbo stalling does happen even with dv fitted as some cant disperse the air

 

No induction kit on the car its standard.

 

the turbo can do this sometimes when it ages as i had this with a ford and theyre terrible for this , in my opinion i think u need a softer spring in ur dump valve as someone said above its basicaly air coming back the way ( back pressure u could call it ) as oposed to exiting the dump valve another way of solving this could be to just check that the piston is moving freely when u rev the car ?? there should be a small vent hole around the dv depending on what dv it is and you can actually see the piston moving freely as above again giving it a clean from the excess oil that develops from the crank and head ventilation valves can help the dump valve also opperate more efficiently .

 

this problem can also cause a bad case of turbo lag that may not be noticeable to u ? as in effect the air coming backwards can stall the compressor wheel as it has nowhere else to go because the dump valve is not opening to release the pressure hence it takes longer for the turbo to spool . a lot of people answer when u ask them what a dump valve is for will prob give u two answers :
1. to keep the turbo spinning
2: to release excess presure in the system

 

Wow I actually took the dump valve to pieces and found one of the cylinders rubber rings stretched, it was being pulled in by the piston ! I took the ring out and put it on the radiator in doors and it went back to shape. I re greased it all and put back together and all was in good working order. Thanks for your replys all all very usefull.