Jasons, I thought the reason no wastegate was needed because it was a VNT turbo - when the car isn't wanting boost the actuator moves the vanes so the gasses mostly just bypass the turbo instead of powering through it.. Didn't realise the EGR took as much as 30% of the EGR gasses either..
Do you still have the EGR blanked off on yours?
it is still blanked off, but having stipped down a vnt turbo, it was clear that all gasses do have to pass through the exhaust turbine wheel.
the benifit of the egr is it can lower boost levels whilst cruising, and it doing gees drop a good few psi too.
As to reduced life, likely if its running higher boost all of the time, but probably only a few thousand miles in the life of a turbo.
I didn't bother plumbing in the water cooling side of the turbo on mine for the same reason, as this only gains a few thousand miles of extra life too.
I don't know if the egr opens as soon as you back off the throttle or change gear, if it does then it is acting as a wastegate in some respect to release excess pressure - I did get told by a turbo specialist that it does have some use as a wastegate, but then I get told lots of things.
I would be interested in a definitive answer as to its use when backing off the throttle/changing gear, does it open?
Do they definatley not use EGR on the race diesels? not even for venting excess gasses?