Really stupid question time.... is a dump valve the thing that makes the hissing noise? Does it have any other benefit? How dificult is one to fit? Are they expensive?

Never had a turbo before hence the stupid questions!

 

yes, not a great deal of benifit only the noise, prices vary depending on the make £40 upto £200+.. pretty straight forward to fit

 

Is it a mechanic job to fit or could anyone do it within reason? Can they be removed with out problem?

 

its as simple as unbolting the standard one on the intercooler in your case and bolting the new one in its place and putting the blanking plug in the return pipe, when you see it you'll see what i mean.

 

We've seen it thousands of times before
Yes, and you'll probably get sick of it quite quickly, most do
No ! Quite the opposite really.
See above, piece of pish
Considering they give no tangible benefit, yes, they're a total con when you could spend that money on something better, or beer, or hookers, or drugs.

 

 

Shouldn't that be Ptiiish!