Massive Lag with 6780S

[RUQWKNF]

Is the 6780 new? I know of the 67-65 and 67-68, but I have not heard of the 67-80.
Who recommended this turbo for your combination?

Nope, old school cast 67 with the displaced GTQ turbine wheel. And yes, we are very lucky to have Dusty on our team. He rates the PTC converters differently than Art Carr and Precision Industries did. That is why you see him asking what rpm you were seeing 0psi at?

The cast 6780 does in fact make some power and was a very popular unit. If it were me, I would see if you could put your buddies 6776 turbo on, get a 3-bolt Buick .63 turbine housing, port the wastegate hole and work on your brakes and tune. That turbo is definitely good for 10.90's.

For what it's worth, we still have THB3-76 Buick 3-bolt housings available. That is the part number for the .63 A/R housing for the 6776 turbo.
Let us know if we can help you.

Patrick
Precision Turbo Level 2 Sales Rep
219-996-7832

 

[MNwe4]

For a quicker and less expensive test I think I may try my friends 6776 p-trim just to see how much difference it makes. I'll be in touch about geting the proper turbine housing.

Thank you everyone for your advice. Once again, great support from the Buick community. Once I figure something out I will post my findings. More suggestions are always welcome.