Power steering MEGA thread

[JeepFreak21]

I would think the faster ratio box would be even harderer on the framerail than the stock box is.

That's a good point, based on 5-90's formula, the torque will be increased with the (numerically) higher ratio. While that will help turn big tires with less driver effort, it would put more stress on the frame rail. Of course, it's pretty widely agreed upon that the frame rail should be reinforced at the steering box anyway. The fourth mounting ear on the box may be necessary if the ratio is too high.
Billy

 

[bdiamond]

That's a good point, based on 5-90's formula, the torque will be increased with the (numerically) higher ratio. While that will help turn big tires with less driver effort

The input torque will have to be raised to turn the tires at a faster rate. With the engine off or no assist it would make turning the wheel with large tires miserable if not nearly impossible with the faster box.

 

[JeepFreak21]

The input torque will have to be raised to turn the tires at a faster rate. With the engine off or no assist it would make turning the wheel with large tires miserable if not nearly impossible with the faster box.

So, does distance = torque or does force = torque?

Output Distance = Input Distance/ratio
Output Force = Input Force * ratio

If 14:1 is our baseline, then woulnd't 12:1 be faster with less torque and 16:1 would be slower with more torque?

Billy

 

[bdiamond]

The ratio I believe is the steering input degrees per degree of wheel movement. So it takes 16 steering wheel degrees to turn the tires 1 degree. It also takes more effort to turn the 12-1 than the higher numeric ratios. If the pump can keep up its no big deal. If you ever lose assist it gets tough.

 

[CRASH]

Why do you want a faster box Billy?

 

[JeepFreak21]

Why do you want a faster box Billy?

I don't think I do, but that's the point of the thread. When I was searching for what to get as a replacement, I found lots of people saying, "get this box, it's faster", so I'm trying to figure out if that's good or bad, along with the other variables.
Billy

 

[5-90]

To simplify -

Faster box = less torque multiplication
Slower box = more torque multiplication.

TANSTAAFL. You can't have it both ways - you have to trade something for something else.

In the case of an off-road rig, you're going to be better off with the slower (numerically higher) box. For a rig that barely leaves the pavement, the faster (numerically lower) box will serve you well.

Why did I want to put a faster box on my wife's rig? To give her more options when it came time to take evasive action (just like I wanted to regear slightly - 3.55 to 4.10, to make the rig a little quicker on the go - and give her four-wheel disc without ABS. She learned to drive like I did - we think safety lies between the ears, and she was trained again in the Academy, even if she didn't take EVOC.)

If you're off-road, especially crawling along, you want the slower (numerically higher) box to reduce turning effort at low speeds.

In either case, I'll recommend at least cross-bracing the front framerails to each other, if not tying the framerails together, adding a reinforcement plate to the gear mounting, and tying the gear body to the opposite framerail (the brace used in the F-body is enough for the F-body, but we're going to put a lot more force on things - larger tyres, more stressful turning environment.)

While not as nimble, a 16:1 or 18:1 box will work neatly for what we want to do off-road, and bracing the framerails and/or steering box would be considered necessary at that point (not only will you be stressing the mounting point severely, not making the front subframe rigid will cause "steering wallow" and effort will be wasted in bending the subframe instead of turning the tyres.)

 

[Milford Cubicle II]

So, is it your opinion that a faster ratio box would be an upgrade?

No, it's a fact. Not only do they have a closer ratio but they're notoriously stronger than the stock XJ p/s box and don't wear out as easily causing death wobble. Especially since I have a street jeep.

What do you use your rig for? Is your rig lifted? And if so, are you concerned about the sensitivity of the steering at speed with a higher center of gravity?

No, I don't need sloppy steering as a "driving aide", I actually know how to drive.

If you just want to cut to the chase and find out what F bodies the box came in, just search.

Maybe you should search yourself before you tell other people to search, because there isn't a thread mentioning which model transam/firebird comes with the upgraded steering box.

 

[cmelo]

Maybe you should search yourself before you tell other people to search, because there isn't a thread mentioning which model transam/firebird comes with the upgraded steering box.

As a heads up, in addition to transam/firebirds/camaro they also came in S10 Extremes. I have one but have yet to swap it in. I'm putting it in my J10 but this thread is making me want to reconsider. One thing that hasn't been talked about much is that these are variable ratio so the fast ratio box's ratio climbs up the further as you get closer to lock in theory giving you the best of both worlds.

 

[bdiamond]

Maybe you should search yourself before you tell other people to search, because there isn't a thread mentioning which model transam/firebird comes with the upgraded steering box.

There are other places to search besides . If you need info on camaro/firebird parts you might try thirdgen.org . Not trying to be a jerk, just stating the obvious.

 

[JeepFreak21]

No, it's a fact. Not only do they have a closer ratio but they're notoriously stronger than the stock XJ p/s box and don't wear out as easily causing death wobble. Especially since I have a street jeep.

But it sounds like it's "notoriously stronger" because a faster box has less torque. Everything is a compromise.

Maybe you should search yourself before you tell other people to search, because there isn't a thread mentioning which model transam/firebird comes with the upgraded steering box.

Maybe you would have better luck searching if you pulled the stick out of your ass. Here's a pretty specific thread on our Jeep Forum... just imagine what you can find on an F Body forum.

http://www.naxja.org/forum/showthread.php?t=85118

Billy

 

[Milford Cubicle II]

As a heads up, in addition to transam/firebirds/camaro they also came in S10 Extremes. I have one but have yet to swap it in. I'm putting it in my J10 but this thread is making me want to reconsider. One thing that hasn't been talked about much is that these are variable ratio so the fast ratio box's ratio climbs up the further as you get closer to lock in theory giving you the best of both worlds.

True for a trail jeep but for a DD or street jeep personally, I would prefer a faster fixed ratio box even at low speeds AKA a parking lot where it's nice to zip into parking spaces and dodge minivans backing out into you. I don't mind the little extra muscle required to turn the wheel. Or maybe that's just me :dunno:

 

[agent98]

For a rockcrawler.

It seems to me that the main factor in the forces applied to the xj frame is not gear ratio but the tire contact patch and what is against the sidewall.

Will a box ratio of a 100-1 on stock tires on pavement crush a xj frame?

 

[Milford Cubicle II]

Exactly. The only place a faster box increases the amount of torque is between the steering wheel and the input of the steering box, so mainly, the steering shaft.

 

[eflores]

if you are putting more stress on the steering shaft you are also putting more stress on the box bolts and your column......

 

[Milford Cubicle II]

True, but it's not transfering through your entire steering linkage like people seem to be thinking.

 

[eflores]

well it does kind of....see its the same amount of force but its applied over a shorter amount of time so its condensed...more shock from the force i guess it what youd say, but this is a street jeep rollin on dubs right:dunno::dunno:

 

[whitneyj]

Kind of pulling this thread back up, it's got some awesome info and was hoping to get it started a little more. Maybe I missed it, but is there a relation to flow with the fixed vs. variable ratio? Looking for more insight on what would be better for hydo assist.

 

[JeepFreak21]

Kind of pulling this thread back up, it's got some awesome info and was hoping to get it started a little more. Maybe I missed it, but is there a relation to flow with the fixed vs. variable ratio? Looking for more insight on what would be better for hydo assist.

I believe the variable ratio will flow more for the same number of revolutions of the wheel, so you shouldn't have a problem with the ram and the mechanical arm being out of sync.

Whether a variable ratio is useful on the trail, I think, still needs to be answered.

Billy

 

[Israel]

Sorry to bring this back up, but I see no point in starting a new thread on the same subject when this one had a good start.

I'm looking to upgrade my steering in a similar manner as Billy, with the hydro assist happening later in the build. Most of my trail time is spent in Moab or casual drives on local forest trails. Right now, I'm leaning toward a Durango box since it will give me more power with the stock pump. It sounds like the stock pump can't keep up with the 808 box and hydro assist, but what if I were to use a WJ pump with a smaller pulley, or a stock pump with the West Texas Offroad mod and a smaller pulley to help at idle?

Also, what boxes came with the 4 mount tabs? I know the YJ and SJ's do. Are there any 4 mount tab 808 boxes?