What is A/R?

The A/R in a relationship that is obtained when dividing the interior area of the turbine where the inner walls are found, through the turbine housing radio from the center to the tongue as the illustration indicates.

A/R values are expressed as .35, .47, .68, .84, 1.00, 1.15, etc.

A small A/R indicates a small interior volume in the small turbine and a large A/R indicates a greater volume.

At a minimum A/R the motor's response is produced at small revolutions per minute but at high revolutions we will not achieve an adacuate caudal. We should always find a compromise between achieving the lowest response possible and have enough caudal at high revolutions.