Stonkin

Ok, this might be the silliest question asked lately,or ever , but what is the difference between the above? or is it just a different name, i ahve seen posts where people are being warned about fitting some kinds of DV due to damage being caused, i have had my car a MY00 turbo for a few weeks, it has a dump valve from scooby world fitted, i hav the bill for about £120, what type would this be, is it ok?

Thanks for any replys,

Steve777

iTrader: (8)

Sounds like you have something like a Forge VTA fitted or similar for that money, cheap bottom of the range job

There are many diferent types and opinions on these. Most tuners recommend fitting them only if you are or intend to run high levels of boost.

I actually run a turbo smart BOV which has an adjustable spring tension and it appears to work much better than the forge VTA I use to run on my previous car.

There seems to be an opinion that running a VTA/BOV against the standard re-circ cause the air fuel mixture to change more than it should. I'm no technical expert on this though.

Stonkin

Ok, thanks Steve, anyone else have any opinions?

Mal26

Most people tend to buy the dump valve for sound and improved looks under the engine bay.
Many people use them without any problems and some report idle problems, poor fuel consumption.
There is no doubt by dumping air rather than recirculating, the ECU tends to compensate by overfueling - this seems to explain why those with decat exhausts and dump valves tend to generate flames out the exhaust when hot.

I think you will find this subject debated as much as whether to fit an induction kit or not!

Stonkin

nice response MAL, appreciated, well its not causing me any grief at the mo!

thank u for your help people,

greasemonkey

As you suspected Stonkin, there's no difference between a "blow-off valve" and a "dumpvalve" - two different ways of describing the same thing. Impossible for us to say what type of DV is fitted at the moment, although it's easy enough to tell if you look under the bonnet and describe it to us, or even better take a picture and post it up here.

There is no need to replace the standard dumpvalve unless you're running enough boost to make it leak under pressure. Even then, if you're running a Subaru ECU, the best replacement is a recirculating valve.

As Mal says, vent to atmosphere valves are bought more for "pose value" than anything else. They don't make your car run any better, and can, to a greater or lesser degree, make it run worse due to the misfuelling characteristic mentioned above.

Road Rager

what is the standard boost pressure then, and what does it need to be turned up to before you need to replace the stock DV

The_Judge

Standard boost is circa 11-12psi. Mine's currently 18psi, and my standard recirc dump valve is more than happy.

Stonkin

thank u grease monkey, a helpful reply as always,

greasemonkey

No problem chap. Take a photo of that valve and we'll ID it for ya. You'll be able to tell yourself whether it's a VTA or not tho. If there are two pipes connected to it (big and small), it's recirculating, and if there's only the little pipe it'll be a VTA.

Stonkin

its definetly not re-circulating (bet i've got this wrong and now look like a prat!) it connects straight to the intercooler and has that bung in the pipe next to it, only remember this as scooby sport had to put a metal tie around the pipe witht he bung inside during a service the other day as it was missing

greasemonkey

Yeah, if the big pipe next to it has been bunged, it'll be a VTA for sure. Does the valve have a series of holes going round the middle of it?

Stonkin

certainly does matey, VTA isnt it, was on the car when i bought it 3 weeks ago, i ahve the bill for £120 from scooby sport, should i leave it on, i do like the sound.