Well, I started off with an abbott (forge) atmospheric dump valve, all worked just fine, however, I got an air induction noise in my JR filter/air intake tube in my front wing, which sounded like a wheel spun by a hamster, it wasnt the noise of the dump valve or the turbo blades stalling, just purely an air reverb in the tubing.
I then replaced this with the abbott (forge) recirc type and all was fine.
I have since changed my induction system completely, having a mesh air filter under the bonnet (with intake ducting under the front bumper). I have now reverted back to an atmos d/v (bailey twin piston) and I get the nice whoosh noise and no air reverb noise.
I dont experience any problems at idle either.
I know some claim a performance difference (2bhp) by fitting a higher spec valve, to be honest I have not noticed and increase in power, no a reduced spool up time.
However this could all be down to the fact that I carried out other upgrades at the same time
I went with the recirculating one myself. Noise difference over the standard one is slight but you do hear a small 'woosh' when changing gear - nothing obtrusive. In terms of performance there is no real difference.
BTW, the Abbott one is the same as the Elkparts one: both are made by Forge.
I went from the plastic one to Abbott (Forge) recirculating DV, and as SteveN says, there is a small whoosh on gear changes. It's barely noticeable, and it does sound slightly different to the plastic one.
I also found that the boost seems to come back a wee bit quicker when changing up the gears, but that may have been due to a tired plastic DV (& running Maptun Stg 3). Certainly don't really notice any power difference between the two.
One major difference is that it does look nice and shiny under the bonnet
Hi sorry dont have a 9000 I have a 900GM and have just fitted the Forge 007 valve. I am very pleased with it power is now much crisper and rolls on and off in a much smoother and feels much more together. I agree there is prob no increase in BHP but I have noticed better and smoother acceleration with faster reaction from the turbo. I would recomend this valve. Next stop for me is ecu, just dont know which one to go for yet.