15g/16t
 

Doing a +T, assuming I have a turbo manifold and downpipe- what modifications need to be done to both a 15G and 16T turbo to fit?

From what I've read 15G just requires reclocking and 16T needs a straight flange. Is this correct?

Depends on which turbine housing you have. 15Gs come in conical or straight flange, 16Ts come in straight or angled flange. Angled flange is the largest outlet of the three, then straight, but only conical flange will bolt up to a stock downpipe. Both will need reclocking and a solution for relocating the wastegate.

16T angled flange will require modification for water return, manifold grinding, downpipe welding and a wastegate bracket.

I don't know if the angled 16T is different, but I put a 16T straight flange in my 940 and I did not have to modify the water / oil lines or the manifold, the turbo just bolted straight up.
I had to drill out the two holes on the turbo though where the studs are when used on FWD cars.

What I had to do is to weld a new downpipe connection and figure out a wastegate bracket.
For that I used the template from http://b230fk.de/volvo/test/austausch-des-atl/2/

This. Find a TD04HL conical turbine housing and it will drop right in.

A straight exit turbine housing will work with this adapter from ClassicSwede:
https://www.classicswede.co.uk/Flat_..._19957914.aspx

Yoshifab sells a wastegate bracket:
https://yoshifab.com/store/15g-waste...r-bracket.html

I've used that adapter from KL as a temporary solution before I got my downpipe welded.
I really wouldn't recommend to use this as a permanent solution though because it restricts the flow a lot (kinda obvious but maybe not...).

It makes the outlet of the straight turbo a lot smaller (as with the actual difference between straight and conical turbos).