What are the Stock Specs for 87 GN Turbo

[Boss358C]

Can someone tell me what the stock specs for the turbo are on my 87 Buick Grand National?

Smitty

 

[strikeeagle]

The stock GN turbo is a Garrett TBO348. Suggest you phone John Craig at Limit Engineering for specs...

 

[trbodon21]

I believe the compressor wheel is 49.5mm and exhaust wheel is 70mm with a .63 A/R ratio. Also the wastegate puck is .75".

 

[nocutt]

Turbo:Buick GN l Compressor Specs (A/R) :TO4 .60 l Compressor Inducer: 1.915" l Compressor Exducer: 2.755" l Turbine Specs ( A/R): TO3 .63 l Turbine Inducer: 1.969" l Turbine Exducer: 2.309" l

To calculate trim is I believe Comp (ind/Exd)^2 x 100.
I also noticed something very perculiar...I was at a turbo remanufacturer and saw two wheels, different brand names but the same specs that come up to the same trim (or very close at least) however the pitch of the blades where COMPLETELY different...making one very superior to the other @ particular RPMs???