Turbo screeching after exhaust change

[S-Express]

Went to Pipe Werx today for down pipe back system, the guys there did a fantastic job with which I'm happy (bit noisy at mo but hopefully it will quieten down a bit over time).
Anyway - turbo was fine before but now, when I boost, I get a sort of screeching sound from the turbo which sounds like the impeller blades rubbing on the turbo body!!??
I'm wondering whether - (because now the exhaust has less back pressure), there is consequently less pressure on the thrust bearing of the turbo? And this has somehow caused the turbo to shag its bearing or caused the impeller assembly to move and the turbine blades ARE infact hitting the body!?
I've only driven 50 miles since and I think the noise has decreased in volume but still sounds rough and I'm worried I've ballsed my turbo - anyone had a similar experience?
Also gutted cos car is costing me over a thousand just to get through mot - thats 3.5k I've spent on it in 11 months (getting it back to decent condition) and thats doing all the work myself
help appreciated peeps

[gnutz2]

Dont think less exhaust back pressure could damage the turbo bearing.

It`s brobably more likely the exhaust itself making the noise, you can get some very strange notes coming from the back of a turbocharged exhaust (screeching and howling).

You said yourself it`s getting quieter which stainless exhausts generally do after time

[jameswkr]

I would have a good look at the supports holding the front section of the exhaust in front of the cats. If these are missing or incorrectly set, the weight of the pipes will be pulling down on the turbo itself.

[S-Express]

When he was building the system, he used a single 200 cell cat and removed the 2 originals. He then used one of the brackets that he cut off one of the original cats and welded that to the new cat. It looks fairly well bolted on.
I did notice that he had to 'persuade' the down pipe with a hammer a few times!
How can shifting the downpipe upset the turbo - its going to move with the downpipe isn't it?
I'm glad you don't think its necessarily a bearing issue - cant afford a recon on it at present!
I'll have a shuftie underneath at the weekend (its up on axle stands again now anyway to replace the front shocks) and check that all's well.

cheers boys

[jameswkr]

" With a hammer a few times" !!! The turbo is attached to the exhaust manifold and the down pipe/ WG pipe ( and the inlet plumbing of course). How do you think its going to move with anything ??

[S-Express]

Fair point - think I'll take the airbox out and take a closer look.

[Acidburn]

Also gutted cos car is costing me over a thousand just to get through mot - thats 3.5k I've spent on it in 11 months (getting it back to decent condition) and thats doing all the work myself

I worked it out about two - three weeks ago and i've spent nearly 2.5k on stuff for the car in the last two ish months not including all the hassle i'm having from the mot. I'd probably say around 3k so far.