Turbine Flow to (Crank) Horsepower:
5 LB/MIN = ~50hp
10 LB/MIN = ~100hp
15 LB/MIN = ~150hp
20 LB/MIN = ~200hp
25 LB/MIN = ~250hp
Pressure Ratio (PR) to Pounds per Square Inch (PSI):
1.00 PR = 0.00 PSI
1.25 PR = 3.68 PSI
1.50 PR = 7.35 PSI
1.75 PR = 11.0 PSI
2.00 PR = 14.7 PSI
2.25 PR = 18.4 PSI
2.50 PR = 22.1 PSI
2.75 PR = 25.6 PSI
3.00 PR = 29.4 PSI
The 0.86A/R makes maybe 50 HP more at the same PSI than the 0.64A/R Turbo.
Both turbo's are GT2860RS's.... Aka the "Disco Potato".
Proud member of "Barrio Fino" Boys 
