Originally Posted by ghunt

I used a 3-4 because 2.75-4 is almost impossible to find. Why they used a 2.75 inlet on the turbo I will never know...

Anyway, the way I got around it was to wrap some 16 gauge aluminum around the inlet of the turbo and silicone it on to give it a little more diameter. Another option is do the same thing with some rubber or something like that- just something that will keep the coupler from fitting so loose.