Oil consumption-knackered turbo?

Hi everyone,
been away for the weekend in our recently acquired (my mate destroyed the engine ,I bought it off him and rebuilt it) L-series hippo, apart from the crap cold starting the engine runs very well and pulls strong.
However the oil consumption has been alarming at times, and tonight I have experimented trying to diagnose the problem.

I have noticed that general town driving and A-roads, max about 60 mph-oil consumption is virtually nil.

Tonight steady 70 mph (3000rpm) on motorway, giving out some smoke, 1.5 ltr gone in 45 mins!

I topped up the oil and for the final hour of the journey sticked to 65mph (2600rpm), with very little oil consumption.

The bottom of the turbo shaft body adjacent to the oil return pipe, is wet as is the EGR flange, I removed the air filter to turbo hose and the compressor side of the turbo internally is very wet as is the pipe to the intercooler.

The car really wants to pull at 70mph(3000rpm) as the turbo is giving loads of boost, I am thinking its sucking the oil through when on this high boost.
What do you guys reckon? Buggered turbo seals? or hiding something else?

Dont want the 'running on' death to occur, nor do I have the shares in OPEC to keep topping the oil!

Thanks in advance

Took off the hose from intercooler to inlet manifold, oil running out.
Compressor housing of turbo can rotate 2cm either way.
compressor shaft has about 30mm movement side to side.
Think Ive just answered my own question,
Just need to get hold of a turbo!

Got a brand new garrett turbo with unlimited mileage and 12 month gaurantee, with fitting kit and next day delivery for £399
cats and Carbs UK in stoke, lookin forward to fitting the bugger now

At 1.5 litres every 45 mins, it should only take you about 50 hours to get your money back !!

As an aside, how badly damaged was the engine before you got it? What did you have to replace already? You'll know then a good quality oil is imperative for a new turbo. Even though you've been piling oil through it lately and it'll be quite clean, I'd be sticking a new filter in and a fresh oil change just to be extra sure there's no swarf lying about from the old turbo which was no doubt about to go bang.

Hi hippolover,
Dont worry I will definetly be doing an oil and filter change! Will also prime the turbo by turning over before I start it up!
Need to flush out the intercooler too its full of oil, likewise the inlet manifold.
Should be fairly easy job, them oil return pipe bolts can be a pain though!

The engine has had a new piston and rebuilt head, and this turbo was a £45 untested special from the scrappys purchased by my mate who was the previous owner. This weekend was the first motorway run the engine has had since it was rebuilt, and it really showed the horrific oil consumption! The engine had to have a new piston because the previous turbo proper popped and 'ran on' luckily it was staled before it could kill the engine.

Didnt want to have a salvaged turbo I am going to keep the vehicle a long time so have gone down the new unit route.

Changed the turbo on wednesday with oil and filter change, flushed the intercooler, did a 350 mile round trip today, 150 of them towing a large trailer, with not a drop of oil burnt!
I put some millers power additive in, and its really cleared out the injectors too, pulling really well now!
Thanks for everyones input!