Huge backfire then no more boost
 

I was driving at full boost (10psi) in 2nd gear when around 6Krpm I heard a huge backfire and ever since get no boost whatsoever. The backfire did not sound normal (fuel dump). Now I hear a whistling sound that gets louder the more I accelerate and the BOV has gone silent (no whooshing sound).

Any ideas? Turbos gone? Hose popped off somewhere?

My first guess would be hose popped off somewhere... turbos would still spool up if they were blown just would make noise and be very laggy or slow. No boost to me means vacuum pressure escaping somewhere.

Chris

edit

I agree sounds like you popped a hose of some where and you got a major boost leak.

Sounds like your blew a coupler. I would start by checking your intercooler piping couplers, starting with the y-pipe coupler if you have a stock y-pipe.

I started to suggest that, but noticed in his profile he has a Series 7. Did they have a soft coupler?

Found the problem
 

See image, the pipe to/from the intercooler cracked and completely broke off. It also explains the big rip in the cover under the bonet that wasn't there before, must have been some force. I temporarily have got the pipe back on with some steel wiring and a pair of pliers until I take it to the shop tommorow. Getting some proper airflow at least.

I was thinking of replacing all the plastic piping with steel (chrome?) piping. If I got a new intercooler (PWR) as it is still standard would it usually come with all this? Would this be the best approach instead of just replacing it with another plastic pipe?

That's not the usual spot for a blow-out. My first thought is that it was abused/damaged at some point. Usually it's the coupler at the other end of that same tube, just above the turbos, that fails first.
Not sure about PWR ICs. If it doesn't come with a metal tube/silicone couplers, I'd just look for another stock one. Here in the States, they're readily available and inexpensive.