One More Power-Steering related Question

I believe that there are kits to modify the pressure relief valve of an old style GM power steering pump, as it is very common to build a street rod with a Pinto/Mustang II front suspension and SBC power. The Pinto rack requires less line pressure than a GM steering box.

nate

__________________ So basically, if I'd gone to PS-101 like a good boy, less hydraulic pressure=less assist, correct? So fundamentally what's needed is either a faster-acting PRV, or, a safe method of reducing the existing power-steering system's total measurable volume/fluid capacity.

-CC

Chris, here's an informative article on a $20-modification to a 1998 Lexus 400 that makes the ps assist variable. Bear in mind that any mods should be done ONLY by someone who fully understands the system(s) AND the dangers involved. As in all driveability changes, the foremost guide should be SAFETY. But, this shows it can be done. HTH, s

Hey I'm the goober who posted that very article here in the first place. #one, it's for modifying ELECTRICAL variable assist, and #two, it got shot down here like a Zero over Pearl Harbor when I first posted it.

I don't want ANY powersteering suggestions from autospeed - they can have them!

-CC

Sorry. I just wanted to point out a 'positive-sounding' project. PS: As technical as you seem to be, you probably already know a variable pressure valve does for a hydraulic circuit what a variable resistor does for electrical circuits; and series, parallel, and complex circuits have quite similar basic "flow" theory. Would have aided us in helping you to know exactly what vehicle you were referring to. Luck with your future projects! s

________________

2008 Kia Optima. I'm coming from an '05 Malibu with the electric assist. Thing was awful. Optima already has "optimal" steering dynamics coupled with more than enough road fee, just want to reduce the boost by a small amount so that it's very aggressive(for a sedan) 4.0degree+ caster can display it's full effect. (The Malibu Caster was speced 2.5 - 3.5 degrees, and my particular example was 3.1deg.) There's very little tech documentation on these KIAs as far as PS is concerned though.

-CC

_______________________ Guess my cat must've gotten all your tongues - or the cables to your keyboards.

Doing some reasearch on "smaller power steering pumps", I ran into this:

About halfway down the page, it discusses the effect of - and modifying the size of - something called a "torsion bar" in the PS system, possibly running into the PS pump itself. Apparently, a thicker bar reduces pressure flow between the chambers, which by inverse relation INCREASES the amount of steering effort required from the DRIVER, and a thinner diameter bar increase inter-chamber flow, which by direct action increases pressure and power steering assist.

If the 2006.5 - present Optimas utilize this technology in their PS pumps, would this be a possible solution to my desire for "heavier" steering?

-CC

The torsion bar referred to is in the control valve in the rack, not in the pump. Basically it changes amount of fluid flow to reduce or increase the amount of assist. If you flunked PS 101 I would not advise trying to Re&Re a rack and modify it.

chris

_________________________ Well, aside from modification, how about fitting a lower-capacity-than- specified PS Pump? Or, as I read on another site, but not quite understanding: Some modification of the pulleys & belts so as to slow down the power steering pump and AC to gain horsepower at the engine?

What I'm aiming at here is: These stock systems are not completely set in stone. They can be safely and legally modified to achieve desired results, or swapped out altogether.

Any thoughts?

-CC

_______________________ Guess my cat must've gotten all your tongues - or the cables to your keyboards.

Chris, you've probably gone further/deeper into this topic than many of us are capable of or interested in going, i.e. more theory and less practical application. What you've described is so close to products that have already come-and-gone. Why don't you investigate the earlier ps systems on like cars of the

50's. Several (iirc), including the ever-so-popular '57 Chevy, used what many of us referred to as "part-time" systems. Some actually felt almost like conventional steering on the open road/at higher speeds. Worked somewhat as an introductory design for consumers set in our ways. [[Hard to comprehend today, but during that same period many were quite reluctant to buy pickups (and cars) with overdrive trannies--due to possibly the fact we did not understand it.]] Such an investigation should at least let you know the idea has, or has had, merit. s

___________________________ "Practical application" is precisely what I'm aiming at here! Problem is SD, at the same time I'm trying to get my head around some power- steering fundamentals. I guess that's what's got you and others stymied. _________________________________________

_________________________ I'm not trying to reinvent the wheel, SD, seriously. ____________________________________

________________________ Alright, in plain English:

Can a 2008 Kia Optima be fitted with a lower capacity/lower assist- granting power steering system without gutting the whole front end of an otherwise fine - and still very much under warranty - midsized sedan?

And I promise I won't take anymore shots in the dark at trying to understand what "torsion bars" or any other individual members of a power-steering system do. Promise! ;)

-CC

I've never been inside a Rack-and-Pinion power steering box, but (for example) the old Chrysler recirculating-ball boxes were (conceptually) very easy to modify. There are two reaction springs (they are 1-turn springs that look like oversized lock-washers) that govern the amount of assist that gets applied. Actually doing the mod requires dis-assembling the steering box and replacing the springs, which most shadetree mechanics back off from (I've overhauled one once, its a pain to get all the tolerances set back correctly, but if you're patient its doable.) For most people its easier to just pay Firmfeel.com or some other company that sells modified boxes. Its perfectly safe and legal, and at least in the case of the old Chrysler boxes you can get a very broad range of assist levels, from "pinkie finger" to barely boosted.

I'm absolutely certain that there are similar springs in the control section of all conventional power steering systems. Whether or not they are practical to replace, and whether or not stiffer replacement parts are obtainable is a different story.

I checked out firmfeel.com and like what they have to offer. They do seem pretty MOPAR focused though, I could call them and ask if a "#2" or #3 steering box might achieve what I'm aiming for with my Korean import. ___________________

_______________________ Thanks again for the website tip. Really though, without making a fool of myself trying to analyze and ASSume what this part of the PS pump or that part of the steering box or another part and a third of the rack does, I'll just say:

I want the simplest solution that will modify my steering system in such a way that more effort("elbow grease") is required from me to steer the car, and less supplied from the PS. Perhaps a "foreign auto repair" or other specialty shop in town knows of such a solution that is compatible with this Hyundai/KIA product.

I will add this though: My GUT tells me that the most obvious solution is a smaller capacity PS pump with smaller fluid volume that can fit or be made to fit within the system of belts & pullies presently under my hood. Just swap the thing out, don't obsess over "torsion bars", "springs", or Nixon's secret tapes(!), and enjoy the tighter feel of a lowered-assist PS system. Tell me if my gut is misleading me.

-CC

ChrisCoaster wrote: _

I just listed them to indicate that the process is possible and has been done, at least for one technology. I seriously doubt they could help you with a Korean rack-and-pinion car.

If you could plumb in a pressure regulator, it *might* achieve what you want. But the thing is, I'm afraid that you would wind up with a system that feels over-assisted up until the point where the pressure limiter kicks in, and then feels under-boosted after that. If you were to put a pressure gauge on your PS pump's supply line, you'd see that the peak pressure depends both on how fast you're trying to turn the wheel, and on what resistance is being encountered (ie whether you're scrubbing the wheels against concrete with the car sitting still, or rolling forward on wet oily asphalt). So if you set the limit so that it feels right on dry concrete, you're going to feel completely unchanged from the way it does now on wet asphalt, and if you set it for wet asphalt, its going to feel like a dump truck on dry concrete.

The reason the reaction spring replacement works in the old Chrysler box is because it is actually changing an analog gain factor in a closed-loop analog control system. Lowering the feed pressure or volume from the pump is trying to elicit a behavior inside the closed-loop control system, but by applying a strictly open-loop input. Not ideal or desirable.

Does Kia have a presence in the Autocross world yet? If it does, then maybe your local autocrossers or those on-line would have a suggestion. It was amazing to me what became available for the lowly Plymouth Neon back in the 90s when it was found to be an outstanding weekend autocross vehicle.

________________________ No offense intended, but the above paragraph means nothing to my brain. When my HS science or biology teachers talked like that, my attention went out the window - literally, four feet from my seat. It's like dictating foreign policy to some folks in Wash DC - they simply don't and won't get it. Dumb it down a little, and I might catch 10-15% of it.

I guess the best thing is to except this modern car as it is, although installing firmer rack mounts, as the MOPAR site suggested, could enhance the linearity of the steering feel, such as knowing more exactly what the front tires are doing as you turn the steering wheel, without actually tightening up the steering feel. Tighter steering rack mounts don't rely on analog feeds or closed loops. ;)

-CC

________________________ No offense intended, but the above paragraph means nothing to my brain. When my HS science or biology teachers talked like that, my attention went out the window - literally, four feet from my seat. It's like dictating foreign policy to some folks in Wash DC - they simply don't and won't get it. Dumb it down a little, and I might catch 10-15% of it.

I guess the best thing is to ACCEPT(not except! - can you believe I'm actually a Democrat and I spell like that?!) this modern car as it is, although installing firmer rack mounts, as the MOPAR site suggested, could enhance the linearity of the steering feel, such as knowing more exactly what the front tires are doing as you turn the steering wheel, without actually tightening up the steering feel. Tighter steering rack mounts don't rely on analog feeds or closed loops. ;)

-CC

Chris, you've got the patience of Job--whomever he was ;) But if this suggestion works, just remember this old shadetree either knew more than he admitted or he just lucked up on a plus. With your persistence, I feel sure you can find a front-end alignment tech who will work with you on this. All this is based on my projects in the past, some that weren't supposed to work but somehow did. Twice, when I adapted newer p/steering systems onto older Chevy pickups (Several, seemingly alike in alterations, did ok w/o this extra step.), they actually had too much assist and caused me to feel similar to you. What rectified them was to get the alignment set with "extra" caster. These projects not being everyday jobs, I honestly am not sure, but I think we set them up giving them more positive caster. Now, I know my pkp-projects were rwd whereas your Korean-Kar is a fwd. Nonetheless, it's gonna be a lot cheaper and quicker to try this than to swap pumps and pulleys or possibly dangerously plumb in pressure regulator valves. (I wasn't about to mention that several companies mfg adjustable brake proportioning valves which I use often when upgrading brakes on older vehicles from single, unsafe cylinders to dual cylinders, or to power using drum-drum on both ends or drum-disc or disc-disc systems--all this adjustment is to more nearly correct an un-engineered brake system so that the "correct" end of the vehicle will break traction first when emergency-braking.) I think a/p already pointed out that using pressure reduction, which he may have mentioned as a possibility himself, may have such a non-linear dampening effect that it could be dangerously unsuspected. All said, IF the added caster doesn't work, the alignment tech should give you a price break in changing it back, because then all the bolt heads should already be clean plus all the 2nd screwing will be taking place along recently-renewed thread-paths! But my honest feeling is that it will at least make you more nearly happy with that fine-driving machine. That last statement I can say with enthusiasm, as a used car operation in which I am merely a silent partner last year bought & sold several "k" vehicles, the vast majority having your name on them and the business having only 2 full-time employees. Many smiles were formed by happy Kia customers! Again, luck to you. And if it works, you will have the whole story! s

________________________ Sounds like a plan. I'll even invite you along and stick you in front of the alignment tech/shop mgr so you can hear:

"Wah-wah-mwahh-wah-wah-wah-whahh-WAHHHHHH.."

(That's Charlie Brown's teacher for: "Caster is built in - it can't be adjusted. Sorry!")

I've heard that happy-horsesiht story from plenty of independents - not just Town Fairs & Sears places. Your idea is noble, sdlomi, and I AGREE: Caster SHOULD be adjustable on ANYTHING STREET LEGAL!!! Tell that to the manufacturers. They'll just look at you with a blank stare.

As far as the handling/feel of my KIA, you can take it or leave it - my wife and I actually like it more than the 2005 Malibu. She had grip that thing with both hands just to keep it in a straight line - and that was after two alignments about a year ago. The '08 KIA is definitely a "one-hander", she declares, especially with the grippy new Mastercraft Avenger LSRs on it. The 4cyl doesn't quite the giddup n' go that the V6 'Bu had, but seriously: What's a lot of power worth with little control?

I'll probably just throw in some stiffer after-market steering rack mounts and be done with it.

-CC

OK, a "closed loop" system is where a controller measures how the system is operating, and then makes an adjustment to an active component to push the system to the desired operating point. Think of a room in a house with an electric heater and a thermostat. The thermostat measures the room temperature- if its too cold the thermo turns on the heater until the room gets warm, then shuts the heater off. Closed loop.

Now, try to imagine how it would work if you had the thermostat set at

72 (an analogy to the factory set of "springs" in the steering box). But you REALLY want the room to be 68 degrees. But you decide that its too complicated to turn the thermostat down to 68 (put stiffer springs in the steering box), and instead you just reduce the voltage of the power supplied to the heater (reduce the steering line pressure). You might get the room to be 68, but when the outside temperature changes (an analogy to the road surface changing so that a different steering force is needed), you're twiddled voltage will be wrong again and the room won't be 68 degrees (your steering will feel just like it did before).