AC and Power steering on FE

[zpiloto]

Wanted to see how much FE was lost due to AC and power steering. Removed the belts and went on a 35 mile test run. Results below. The beginning temperature was 50 and ending temp was 60.
Since my wife(who is tiny) drives this car sometimes I don't think she could handle the extra effort required at very slow speeds to turn even though I had no problem with it.
I also want to see how much lost occurs just due to the AC belt but due to time constraints I didn't have time to test that today.

First run : Normal set up
Gal used .9
Avg MPG 37.0
Avg MPH 34

Second run: With removed belt
Gal used .8
Avg MPG 40.2
Avg MPH 36

I was surprised with the results I was only expecting a 3% increase. With the power steering belt replaced it might fall down to that range. Will any damage result from driving with out the Power Steering? There is a noticeable increase in acceleration with out it.

[SVOboy]

So, this is for both ac and ps disabled? I kinda wonder a chart between ac and windows down fuel economy based on differing speeds, was gonna suggest it in a while.

[zpiloto]

Yes both AC and PS disabled. I went to see about a belt for just the PS but the auto parts store didn't have one. I'll run it like this for awhile until what I call the "Texas summer blend" hits here in a month or so then I'll hook up the AC and watch the FE drop.

[JanGeo]

Wow that is substantial - the AC pulley should spin pretty freely if the AC is off - check it and see - didn't think the PS was going to make that big a difference. Do you have variable assist?? I notice that my idle only drops about 20rpm when I work the steering back and forth at crawling speeds in neutral and I have variable assist that is speed sensitive - not sure how they/it determines speed however. Scion xB 2006. Might be interesting to run the PS with an electric motor and see how much power it takes. The minicooper uses an electric motor to run the PS.

[SVOboy]

My mom's (1993 camry) power steering will slap it up from 750 to 1000 when I spin the wheel around, it's so sad, :'(

[zpiloto]

The AC pulley spins freely. Don't think it's power assisted never noticed any increase in RPM as you describe. The 626 a heavy car 3964 lbs. with a 2.0L. I guess a little bit helps alot. I was suprised at the increase also.

[SVOboy]

3964 pounds? Are you kidding!?!?!

That's insane!

[rh77]

3964 pounds? Are you kidding!?!?!

That's insane!

It's that "Swing" mechanism that moves the air vents, I knew it!

Seriously, could you install a clutch mechanism on the PS pulley, like the A/C, so you could engage it when you need it -- like parallel parking or when the wife drives it, for example?

RH77

[philmcneal]

you must have strong arms. This camry 91 I have, it took all my stregth just to FAS into a parking stall. But you seem to do it all the time!!

Although the increases are interesting... does this mean less wear and tear too? HMMMMMMMMMMMM

[philmcneal]

damn double posts... i should have been more patience.

[SVOboy]

I dunno if it means less wear and tear, on the power steering pump I spose. Driving my crx isn't hard, prolly cuz I don't have very wide tires.

[kickflipjr]

Saturn never made the SL2 without power steering. So no PS removal for me.

[SVOboy]

Saturn never made the SL2 without power steering. So no PS removal for me.

The honda people loop the fluid from the pump into itself so it never moves and therefore never engages the pump.

[brick]

Will any damage result from driving with out the Power Steering?


I can't prove anything but I would be concerned about the longevity of disconnecting the PS pump on a steering system that is designed to be boosted. Steering at high speeds doesn't take much effort but low speeds require a substantial increase in the torque that you have to apply to the steering wheel, as you observed. This means much more stress on everything between your arms and the rack, and especially the U-joints. Wear could be greatly accelerated, especially with a heavy vehicle. I've tried tried FAS coasting into a parking space once or twice and I just can't imagine that it's doing anything good to my car.

It would be great if there were an easy/cheap way to replace the belt-driven PS pump with a load-sensitive electric version. Dare to dream, right?

[rh77]

To keep the gaskets primed and the pump working, it probably needs to run once in a while -- kinda like running the A/C every once in a while in the colder months to keep everything in check. Maybe take a drill and hook it up to the pump once in a while get the fluid moving once in a while.

As far as operating it manually, any manual steering operation would take a toll on the U-joints and such, just because it's easy for someone to steer inside the car doesn't mean the same forces aren't applied to the mechanicals from the pump to the wheels or the steering wheel to the pump or gearset. Manual steering basically has a gear box with grease in it hooked to the rack, right? In this instance, the grease is a bit thinner and can withstand higher temperatures and pressures (and it has a pump to help it along). Sooo, does that mean it can operate independently of the pump -- it does with the engine off. What I don't know is how it works with the engine off. When you turn the wheel, are you acting as the pump? Or are you turning a gear set? Or both? I think the anwer lies there...

I think that the mechanicals of everything can withstand the pressure, perhaps execept for whatever translates the turning motion into the rack: pump, gear, or both. Any thoughts?

And still, can you rig an A/C clutch to it to run it whenever you want? That sounds reasonable to retrofit.

RH77

[JanGeo]

All I know about my xB Scion is that the owners manual says not to steer with the engine not running - I tried turning the wheel when the engine off and it REALLY didn't want to move at all even with 38psi in the tires and rolling slowly. Keep this in mind however - the gear box for the steering has light ATF type fluid not 75-90W gear lube so without the hydralic pressure pushing the rack around I would think you could be doing damage. I will talk to my brother about it as he has worked on these systems and see what he says later today.

This morning we move my Geo into the barn to start the welding process for the front suspension WOO WOO!! 4 months later . . .

[MetroMPG]

ALl I know abobut my xB Scion is that the owners manual says not to steer with the engine not running

does the xB have electric power steering?

This morning we move my Geo into the barn to start the welding process for the front suspension WOO WOO!! 4 months later . . .

start a new thread! "reviving a miser". with pictures please. i'm going to be about a week or 2 behind you doing the same work to the forkenswift.

[rh77]

ALl I know abobut my xB Scion is that the owners manual says not to steer with the engine not running

I think nearly all vehicle owner's manuals say this as a legal/safety statement, so people don't loose control because they didn't realize that the steering gets harder. Even if it's electric, cars have to have the ability to steer (although difficult) with the engine off, again for safety purposes. I guess it comes down to how it works exactly if damage will be done.

RH77

[MetroMPG]

good point. you have to be able to steer the car if the engine quits.

reminded me... when i was in university, i used to teach defensive driving part-time. one of the topics was: "what to do if your engine quits while driving" (the teaching car was a jetta automatic).

we would discuss the effects of losing engine power on steering & braking, then demonstrate it in a parking lot or on a quiet street.

depending on the skill of the student and the traffic conditions, for the duration of that lesson (after moving on to other topics), at random times i'd reach over to the ignition and "stall" the engine for fun while we were driving around.

[zpiloto]

Was able to find a belt for just the PS today went out and did my standard 41 mile test loop. These results are with just the PS and no belt on the AC. Temperature was in the mid 70 with south winds gusting to 25 mph.

First run: No belt on AC or PS.

Gal used 1.1
MPG 37.7
Avg MPH 40.0

Second run: Belt only on PS

Gal used 1.1
MPG 37.4
Avg MPH 40.0

So it appears that the the PS drag is minimal but there is around a 7% loss of FE caused by the AC pulley belt on Casper the lead sled. Which seem like alot. I wonder if the belt was to tight or if the AC getting ready to go. The pully spins freely. I’m just going to leave it with the PS hooked up.

[JanGeo]

Well about 3 hours of moving it closer to the welder and jacking it up with 3 jacks and a turnbuckle to pull it into alignment, a small bracket of steel has been welded into place to support the front edge of the swingarm. Almost all of the bottom of the wheel well tower that the a-arm pin bolts to was rusted away. Took a bunch of photos before, during and after. The left side looks ok but we will sealing it up with cosmoline to prevent further damage. Apparently the support is hollow and fills with water and does not drain. Was really weird driving so low to the ground and the clutch was grabbing way at the bottom of the travel. No power steering felt a little weird too. Anyone know if there is a source of tower sections to replace the rusted area?

[JanGeo]

Hey anyone figure out how much power steering fluid goes into the entire system?? I am trying to find out about my xB but no one seems to know - need to spend $40 for fluid if it takes a liter but less if only half a liter is needed. Getting ready to order the SynLube this week as it is time to change the oil for the first / next to last time.

[JanGeo]

NEVER MIND! seems I can't really drain the fluid out anyway so a liter it is - turns out the container for the fluid on the pump is pretty big and the line runs are going to need draining so I have to get the Liter of the Synlube. It also is in constant circulation so using better fluid will help and it is only good for 5 years anyway.

[molecule]

if p/s removal is desired...but there is fear of lubrication...
the high pressure valve can actually be removed from the pump itself
so its just a closed loop system

there is no side effect of running your p/s without fluid (and the belt off)
if you have seen what makes p/s work it is only springs and pins...
http://www.g2ic.com/forums/showthread.php?t=88673&highlight=power+steering+removal
however, if you remove the belt...you should also disconnect the line
so the high pressure valve is not acting on the system
if you disconnect the main line from the pump your steering is basically a manual rack at that point...

[JanGeo]

Hey I think you are totally correct - the power is applied at the shaft where it enters the rack from the steering shaft and boosts the effort. I will be keeping it connected as turning the wheel at slow speeds with a 3 turns stop to stop turning ratio and a slippery steering wheel is not going to be as easy as the Geo which I can palm. The Synlube has slippery stuff in it so it should work a lot better and reduce engine loads - not sure about higher RPM however.

[philmcneal]

another mod yet i can't do due to my lack of skills in the automotive industry ;(

although I'd keep AC though... sometimes you just need it. (like defogging windows)

[pertyfly]

Why would you need AC to defog your windows? Generally you would change the "heat setting" but don't need AC . . .

[diamondlarry]

Why would you need AC to defog your windows? Generally you would change the "heat setting" but don't need AC . . .

That is correct, you don't NEED A/C but A/C defogs the windows twice as fast.

[philmcneal]

i rather have the ac on for 10 seconds and see than turning on the heat and waiting for 20 seconds? THat's just me unless.... AC really robs power

[SVOboy]

A/C is the biggest ladron out there. I just blast my heat.

[JanGeo]

Hey I don't see any loading on my engine when I turn on my AC - I guess it depends on the BTUs that they put out but the Office AC unit I have in the office takes about 500-600 watts which is less than 1 HP so I have a hard time seeing where all these "losses" are coming from - going to.

[SVOboy]

Mehbe a/c has become much more efficient since my time. In my mom's car the idle will jump up 3-400 rpms when a/c comes on, 250 when the wheel gets turned, *shrug*

[JanGeo]

Yeah that sounds like it - the variable scroll compressor in my xB is probably a very light load on the motor and the output is not as many BTUs and the power steering is only providing a little assist at low speeds and is variable assist controller by the computer. When I was under the xB changing the oils I saw the computer control input to the pump.