I have a GT2560R, and I'm currently using this banjo connector for both in and out: 14mm Banjo Fitting Set for coolant lines - 3/8" Barb : atpturbo.com
The problem is that it keeps leaking. I have basic worm clamps holding the lines on, and it worked fine for a while, then started leaking, so I tightened them up. That fixed it for a while longer, but it recently started leaking again and further tightness does not fix anything.

I'd like to stick with a banjo fitting on the turbo as it fits nicely as-is, but I need something different to connect.

Should I just get a different type of hose? I'm currently using the basic black coolant hose from the auto parts store.
Different type of clamp? I hate the worm clamps, but I'm not familiar with other options on that size tubing.
If I do an AN fitting there, I'll still need to just cut the other end off to connect it to the engine, so that seems like unnecessary cost since I'll still have barb fittings anyway.

 

are they cheap thin dept store clamps? not all are created equal, even if both are worm style. also I'd look into silicone hoses

 

They are definitely cheap clamps. Are the clamps from McMaster going to be good quality? I'd link to an example, but their website is being AWFUL today.

 

Auto parts stores sell these things, you should be able to find some to fit coolant and fuel hoses but not much larger...



Hose clamps can be over-tightened, too. It deforms the case holding the screw and makes the clamp useless.

 

If you run proper clamps and hoses, the problem should be fixed. Lot's of OEM's run that for hundreds of thousands of miles. Your hose might be old and stretched and/or too big for the fitting, only so much a worm clamp can do in that case. and then there's the cheap clamps which will fail after just like 2 inch pounds of tightening

 

Sounds like I over tightened the clamp. I'll buy some new rubber hose and some better clamps on my way home and see where that gets me. I guess I didn't realize there were better worm clamps.

 

I bought some new clamps, the kind pictured by deeznuts, and some 5/16 fuel hose (that **** cost me $40!). I pulled the old hose off, made up the new hose with boiling water and the banjo fitting, and some heat wrap to protect it from the turbo hot side. Then I could not get it onto the thermostat housing. The stock line is clearly 3/8. So I cut off the leaky end of the old hose and reused that. It's a little shorter than I'd like, so I'll replace it again someday I'm sure, but with the new clamps hopefully that solves the leak.