Nissan TD27 dump pipe query

Yeah, I considered that, but it's not just a "hole" but a sort of rectangle shape about 90mm long and about 50mm wide with a few rounded corners and a bulge at one other corner.
The cross-sectional area of the turbo outlet would be about the same as the 3" pipe, maybe just a gnat's wisker shy of it.
Thanks for your comment
Oskar

Ok so you wiil have to make up your own flange to bolt to the torbo housing and what ever size pipe you have will do ok. Another flange at the bottom to bolt the exhaust onto.

That's what I've already done... it's sitting here beside me all nice and professional looking.
I just need to know that what I'm doing (with the 3" dump-pipe) is OK and won't cause damage to my particular sized engine.
Oskar

Isn't it going between the Turbo and the exhaust so size does not matter as the 2.5 exhaust will give you the restriction you require. A 3" exhaust all the way would be to big.

Thanks for the info Ken.
Very interesting and no doubt spot-on.
The 2.5" exhaust already fitted is a straight through system but it finishes just below the turbo outlet pipe. (a narrow cast iron section about 250mm long that I want to replace with a larger section dump pipe)
I have been told that a complete 3" exhaust would be overkill on this vehicle with a 2.7L engine and that the 2.5" exhaust system is right for the job. No problem there.
As I already have a 3" dump pipe to fit the turbo (made in complete ignorance of what would be best for the job), my query was whether or not the 3" job (straight off the turbo for about 250mm and onto the 2.5" system) will have a detrimental effect on the engine.
It's not really restriction as such, as the rest of the system is 2.5" straight through i.e. the rest of the system is smaller by .5" anyway.
I don't really want to have to remake the dump pipe out of 2.5" if I don't need to.
Thanks for your experience and advice
cheers
Oskar

Thanks mate.
That's about what I reckon.
I'll let you know how it goes.
Oskar