Expert: Brad Sears - 9/28/2009

Question
how much horsepower will my 66 Corvette loose if I convert the car to power steering (an original setup for the car)?  The motor is the original 327/350hp motor. Thanks! Steve

Answer
Ok, since my last answer was not adequate and did not list a number, I will take the time to try a better answer. there is no one number that can be assigned to the power drain of power steering. That is because it is a variable hydraulic device. When the steering wheel is in the straight ahead position the control valve spool in the power steering unit directs the hydraulic fluid that is pumped by the belt driven pump into a by pass modes so that the fluid is just circulating through the system. the amount of power needed for this is in the fractional horsepower range, just what power is used to overcome the friction of the drive belt and windmilling of the pump. If my memory is correct test that I did when teaching automotive technology at a university measured about 1/16th of a horsepower. So, driving down a straight road that would be the horsepower loss. Now when turning the steering wheel the spring loaded control valve in the PS unit will open the spool valve allowing fluid to flow to one side of the system or the other depending on steering input and resistance of the front wheels to be turned. This means that the power needed and pressure inside the unit will be different at each different need. At full lock with the car at rest and on soft ground the need for horse power is the greatest and the most engine horsepower will be needed. Tire size, vehicle weight, tire pressure and surface texture all contribute here. Again this is from memory but about 16 to 20 horsepower  in the most extreme conditions could be needed. I hope that this answer clears the air a bit. The answer is, it depends.
Brad