Horsepower loss

[Micah Pohlman]

I'm going to post this question on a few different forums because I know there will be more than a few answers, anyway...

How much horsepower is used (lost) with power steering? I'm looking for actual hard empirical facts, not any of that "I think..." BS. I have enough of my own "I think.." BS going on in my head.

 

[RemCharger]

While cranking hard in a parking lot? Cruising down the highway? Straight down a dragstrip?
I'll put it this way, it's very hard to see any gain on the timeslips .
"Dyno slips" would be hard to find on p/s pumps.

 

[Don Frelier]

I once set up a power steering pump and gearbox on a pallet and used a 1/4 hp electric motor to test.
Of course I didn't have a front end and wheels sitting on asphalt but the 1/4 hp electric motor had no isssues spinning the pump.

 

[ruffcut]

Make enough HP and it won't matter!

 

[Kern Dog]

Mopar Muscle or Mopar Action magazine did a short article on this.
Since the OP is expecting an exact answer, I’ll skip giving him one since I am not 100% are of the number.
Why even worry about this anyway?
What difference does 5-8 HP mean in a 3800 lb car ??

 

[beanhead]

I once set up a power steering pump and gearbox on a pallet and used a 1/4 hp electric motor to test.
Of course I didn't have a front end and wheels sitting on asphalt but the 1/4 hp electric motor had no isssues spinning the pump.

I bet that pallet corners like it's on rails!

 

[BB BELLA]

it's the lbs. up front that make the timeslip difference! you have to account for horsepower loss and how much more weight you have with the pump/box/belt/pulleys/fluid

 

[dvw]

Other than the extra weight you'll never notice. If it's a street/strip car unless it's really on a diet, I'd use what you like. Same with the alternator. I disconnected my belt last year looking for a few .0x in ET. Made zero difference.
Doug

 

[Runner 68]

Mopar Muscle or Mopar Action magazine did a short article on this.
Since the OP is expecting an exact answer, I’ll skip giving him one since I am not 100% are of the number.
Why even worry about this anyway?
What difference does 5-8 HP mean in a 3800 lb car ??

Especially when an engine is making 500+ horse power.

 

[Photon440]

How much horsepower the pump loses depends on so many things; which type of pump, as there are several. Do you mean while driving straight, or turning? Turning while barely moving there by adding resistance, or at high road speeds? Power loss at idle, or maximum speed - what's your redline and what size pulleys??

This article shows GM pumps draw under 4 hp. at high speeds, and offer a lower alternative. Pulling Less Power - New test equipment uncovers excess horsepower loss in power steering pumps - NASA Speed News Magazine

 

[dvw]

A statement from the above mentioned article. Quote: {For example, suppose a racecar is at its most deficient in a given turn, with data showing, say, 500 psi of pressure and 2.3 gallons per minute of flow, equating to consumption of 4 hp} That's a 4hp loss when its at its highest consumption of power. Not much.
Doug

 

[RJRENTON]

How much horsepower the pump loses depends on so many things; which type of pump, as there are several. Do you mean while driving straight, or turning? Turning while barely moving there by adding resistance, or at high road speeds? Power loss at idle, or maximum speed - what's your redline and what size pulleys??

This article shows GM pumps draw under 4 hp. at high speeds, and offer a lower alternative. Pulling Less Power - New test equipment uncovers excess horsepower loss in power steering pumps - NASA Speed News Magazine

Great explanation.....the MAXIMUM HP consumed will be at the maximum pressure delivered.....the steering box at either end point, and the pump will be delivering its maximum pressure, typical 1500-1800 psi. The volume is fixed by design, either a cam/roller type, Federal/Thompson or sliding vane type, Saginaw, and is POSITIVE DISPLACEMENT design. At those conditions, all HP consumed is released in fluid as HEAT(Btu equilivant of HP) plus internal friction losses plus belt losses. There is no real exact loss pinpointed . Just talking out loud.....
BOB RENTON