Im a nit naive to modding so bear with me.......
is there a dumpvalve already fitted to the STI7
Whats its real purpose
and if not is there any good reason to have one fitted?

 

The dump valve is known as the wastegate, its already fitted and does a fine job
You will find that all petrol turbocharged cars have some form of wastegate fitted and changing it to an aftermarket one will give no improvement in performance.

Tony

 

Thnx for that Mate... the whole world is making more sense now
P.s looks like im still a nit....LOL

 

That ok check out www.sidc.co.uk thou for info on scoobs in general

Tony

 

It's easy enough to change a wastegate actuator ( 3 or 3 bolts dependant) but with average tuning usually unnecessary to do to so.

A

 

However as Tony said, changing the blow off valve (BOV) aka dump valve will have no gains in performance.
Standard recirculating BOV is adequate and quiet. There are people who change to a vent to atmosphere instead of recirculating because this makes more of a WOOSH noise. All very well if you like wooshes but I suspect it could result in a marginal performance degradation.
More important things to spend money on first.
Hope this helps.

 

The dumpvalve is not the same as a wastegate!

A wastegate is a bypass valve for the turbo that lets exhaust gas bypass the turbo when it is opened and is usually used to control the boost pressure.

A dumpvalve vents inlet pressure when the throttle is shut suddenly, and is not part of the turbo

The biggest difference is that a dumpvalve works on the inlet to the engine and the wastegate on the exhaust

You can get aftermarket dumpvalves (The Impreza already has a recirculating dump valve as standard) but it is very difficult to change to an aftermarket wastegate as it is normally built into the turbo

Paul
Edited for spelling mistakes

[Edited by pnebbs - 5/12/2002 7:52:46 PM]