yeah, well at the moment we ave got where the EGR valve use to be to play with, but the control is going to be the challenge.
make the path too easy to take and the turbo will not spool properly, dont take enough and the turbo becomes a restriction and the pressure goes up.
One option might be to alter the mapping of the EGR valve coupled with a narrow outlet post valve side. this could either be done via the ECU or by a seperate control method to activate the solnoid in it.
the downsides to this is either design and build a 'mini' ecu for some pre-programmed values, or cost\time to get a remapper to 'muck about' with things. and then istill need to devise a method to read the pressure while all this is being tested.
With the % increases of things i am not really sure i want to risk tapping the exhaust manifold directly at this time, so i need to be able to utilise a blanking plate of some shape still.....
An External wastegate would not cope with the gas temps so it pretty much out the question
It is not going to be easy i dont think....
thanks for the thoughts though
Ps the 'real' solution is a turbo with a bigger hot side - but VNT control has it's own problems and non vnt units are too laggy