wastegate is a valve in the turbo exhaust housing and controls boost pressure.
blowoff or dump valve is a pneumatic valve fitted before the throttle body to vent stalled boost pressure created when lifting off the throttle from stalling the turbo , this can damage it and causes lag
You might want to try and get your hands on a book called 21st Century Performance which explains an awful lot about modern-day car workings. Personally, it has been indispensible in getting to grips with how my car works and what everything does (and how/why). I ordered mine directly from Autospeed in Oz, though I think Amazon might be carrying it now.
WHSmith are also quoting up to 2 weeks delivery, although I hope they'd be quicker. Direct from Autospeed with the express delivery option it is only about £2 more that WHSmith and arrives in about 4-5 days. Without the express delivery it'd be about the same price and probably 1-2 weeks.
Are we seeing a pattern here? http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle >
Having said that I'd probably have ordered mine from WHSmith if I'd known they did it, at least then if there are any hassles you can go and hit them with sticks untill they sort it out. You'd need a mighty big stick to hit anyone at Autospeed!
Excuse me for correcting u , but the wastegate is there to control boost pressure via actuator , boost solenoid and ecu/boost controller , to prevent overboost not to prevent the turbo from overspeeding.
Yeah you are right.
I wrote a really long answer explaining how it worked, got ####ed off, shortened it and know I realise I left the main reason out which was boost control.
You should have seen what I was going to put about Blow-Off Valves until I decided to 'go with the flow' and put down what everyone else thinks they are fitted for. It would have been too controversal and I can't be arsed at the moment to explain myself