Borgeson Install for Beginners.....Like Me

[cavboy78 28]

My "return to center" issue is barely noticeable to me. My front suspension has been completely replaced in the last 3-4 years, so I was starting with good components. I used the OEM idler arm (not the roller) and installed using the Saginaw pump. I'm not running very much caster right now though, and adding some positive caster would most likely fix the small issue. All in all, it was well worth it and steers so much nicer now. glad i put it on!

Edited June 18, 2013 by cavboy78

[grendi 16]

i started with all new manual steering components as well, but i don't have any return to center with the borgeson box.

 

...but it works perfect with the old 16:1 box from the powersteering.

 

at least the replacement steeringbox works better then the first box that i received.

[buening 63]

grendi, what are your caster settings?

[grendi 16]

+max (more then 4°)

[grendi 16]

+max (more then 4°)

[Big Secz 26]

The issue I had was the wheel had no return at all. You would turn the wheel and it would stay in that position. Then after maxing out my caster I was able to get it to return 1/4 of a turn. Keeping the car in a straight line was a challenge, not to mention it suffered from some bumpsteer which just added to the problems. All-in-all I think it would have been worth it to spend the few extra bucks for a power rack setup. That's just my experience though.

[Big Secz 26]

The issue I had was the wheel had no return at all. You would turn the wheel and it would stay in that position. Then after maxing out my caster I was able to get it to return 1/4 of a turn. Keeping the car in a straight line was a challenge, not to mention it suffered from some bumpsteer which just added to the problems. All-in-all I think it would have been worth it to spend the few extra bucks for a power rack setup. That's just my experience though.

[buening 63]

Lengthy post alert! I'm not an automotive steering system designer, but I did stay at a Holiday Inn Express last night :lol:. I am trying to wrap my head around how a simple steering box swap can affect the return to center....unless people are getting faulty or worn Borgeson boxes that is adding resistance to the drag link and tie rods. From my experience/knowledge, the return to center is a function of caster and somewhat the idler arm bushing. "Return to Center" is the result of something called mechanical trail, which is a function of the steering axis angle and the tire diameter. The center of the steering range is its neutral zone, and is what keeps the car tracking down the road in a straight line. Think of those stock spring perch bushings, if you try to move the perch the bushings will push back to its natural state. This mechanical trail acts like that bushing and pushes the steering system back to the neutral zone. The larger the mechanical trail, the more return to center but also the more steering effort that is required (due to it wanting to always return back to center or its "neutral" zone, more trail = more returning force = more force to overcome this returning force when turning the steering wheel to make a turn). In order to increase the mechanical trail, you need to increase the steering axis which is precisely what caster does, or increase the tire diameter. Going to a smaller diameter tire negatively affects the return to center.

 

Below is a decent but confusing description I found of what mechanical trail is, and I've attached a diagram to help with the description. Pictures are worth a thousand words sometimes. The diagram has the angles exaggerated for ease of view.

 

Looking at the car from the side:

 

In an older car, there would be a kingpin around which the front wheel would rotate when steered. In a newer car, there will be a pair of ball joints, upper and lower, about which the front wheel will rotate. If you draw a line between the centres of the two ball joints (tracing what would be the axis of the kingpin, if there were one), you have the "steering axis". The steering axis normally will lean backwards, so that its upper end is behind its lower end. The angle thus created is "positive caster". Now imagine that you extend this line, the steering axis, down to where it meets the ground. Let's call the point where it meets the ground "X".

Now take the centre of the front "axle", or wheel hub, and drop a line from that centre vertically down to the ground. Call the point where it meets the ground "Y". When the car is stationary, the centre of the tyre contact patch will be at "Y".

Finally, you have to take on faith that, when the car is in motion, the centre of the contact patch migrates backwards from "Y". That new point, which surprisingly remains relatively constant for most tyres on most cars, we'll call "Z".

You always want "X" to be ahead of "Z". This distance is called "trail", and so long as the number is positive, with "X" ahead of "Z", the steering will tend to be self-aligning, so that as you add lock the steering weights up and wants to return to centre.

Although "X" to "Z" is the total trail, from "X" back to "Y" is the mechanical trail. From "Y" back to "Z" is the pneumatic trail.

When people talk about adding caster to a car (that is, changing the angle of the steering axis), what they're mainly after is changing the distance of the mechanical trail, in order to alter the self-aligning torque and thus potentially making the car more stable straight ahead or, conversely, lightening the steering weight.

 

Just trying to explain the mystery of return to center, for those that are curious.

 

 

 

 

 

I believe Borgeson also uses these same Toyota boxes on their Corvette kits, yet a google search for return to center issues on vettes with a borgeson box doesn't come up with anything. Something with our cars just isn't meshing well with these boxes, whether the box being incorrectly installed, faulty or worn boxes, or binding in the steering or suspension. Some mustang owners are happy with the boxes and don't have the issue, while others have the return to center issue. Since this isn't an everyone has-the-issue-situation, I wouldn't think it would be non-compatible box.....or maybe those that don't have the issue aren't as picky with return to center.

 

A thread on another forum by Big Secz also has people mentioning burping the system fixed it: http://www.allfordmustangs.com/forums/classic-tech/300059-borgeson-steering-issues-2.html

 

 

I also found this from their website (see the bottom), although it really doesn't help much imo: http://www.borgeson.com/troubleshooting/Borgeson_Power_Steering_Conversion_Tech.htm

 

Something else I found: http://www.freeasestudyguides.com/steering-wheel-returnability.html

 

 

Anyways, just my thoughts on some stuff and not saying anyone is doing it wrong or are full of crap.

[buening 63]

Lengthy post alert! I'm not an automotive steering system designer, but I did stay at a Holiday Inn Express last night :lol:. I am trying to wrap my head around how a simple steering box swap can affect the return to center....unless people are getting faulty or worn Borgeson boxes that is adding resistance to the drag link and tie rods. From my experience/knowledge, the return to center is a function of caster and somewhat the idler arm bushing. "Return to Center" is the result of something called mechanical trail, which is a function of the steering axis angle and the tire diameter. The center of the steering range is its neutral zone, and is what keeps the car tracking down the road in a straight line. Think of those stock spring perch bushings, if you try to move the perch the bushings will push back to its natural state. This mechanical trail acts like that bushing and pushes the steering system back to the neutral zone. The larger the mechanical trail, the more return to center but also the more steering effort that is required (due to it wanting to always return back to center or its "neutral" zone, more trail = more returning force = more force to overcome this returning force when turning the steering wheel to make a turn). In order to increase the mechanical trail, you need to increase the steering axis which is precisely what caster does, or increase the tire diameter. Going to a smaller diameter tire negatively affects the return to center.

 

Below is a decent but confusing description I found of what mechanical trail is, and I've attached a diagram to help with the description. Pictures are worth a thousand words sometimes. The diagram has the angles exaggerated for ease of view.

 

Looking at the car from the side:

 

In an older car, there would be a kingpin around which the front wheel would rotate when steered. In a newer car, there will be a pair of ball joints, upper and lower, about which the front wheel will rotate. If you draw a line between the centres of the two ball joints (tracing what would be the axis of the kingpin, if there were one), you have the "steering axis". The steering axis normally will lean backwards, so that its upper end is behind its lower end. The angle thus created is "positive caster". Now imagine that you extend this line, the steering axis, down to where it meets the ground. Let's call the point where it meets the ground "X".

Now take the centre of the front "axle", or wheel hub, and drop a line from that centre vertically down to the ground. Call the point where it meets the ground "Y". When the car is stationary, the centre of the tyre contact patch will be at "Y".

Finally, you have to take on faith that, when the car is in motion, the centre of the contact patch migrates backwards from "Y". That new point, which surprisingly remains relatively constant for most tyres on most cars, we'll call "Z".

You always want "X" to be ahead of "Z". This distance is called "trail", and so long as the number is positive, with "X" ahead of "Z", the steering will tend to be self-aligning, so that as you add lock the steering weights up and wants to return to centre.

Although "X" to "Z" is the total trail, from "X" back to "Y" is the mechanical trail. From "Y" back to "Z" is the pneumatic trail.

When people talk about adding caster to a car (that is, changing the angle of the steering axis), what they're mainly after is changing the distance of the mechanical trail, in order to alter the self-aligning torque and thus potentially making the car more stable straight ahead or, conversely, lightening the steering weight.

 

Just trying to explain the mystery of return to center, for those that are curious.

 

 

 

 

 

I believe Borgeson also uses these same Toyota boxes on their Corvette kits, yet a google search for return to center issues on vettes with a borgeson box doesn't come up with anything. Something with our cars just isn't meshing well with these boxes, whether the box being incorrectly installed, faulty or worn boxes, or binding in the steering or suspension. Some mustang owners are happy with the boxes and don't have the issue, while others have the return to center issue. Since this isn't an everyone has-the-issue-situation, I wouldn't think it would be non-compatible box.....or maybe those that don't have the issue aren't as picky with return to center.

 

A thread on another forum by Big Secz also has people mentioning burping the system fixed it: http://www.allfordmustangs.com/forums/classic-tech/300059-borgeson-steering-issues-2.html

 

 

I also found this from their website (see the bottom), although it really doesn't help much imo: http://www.borgeson.com/troubleshooting/Borgeson_Power_Steering_Conversion_Tech.htm

 

Something else I found: http://www.freeasestudyguides.com/steering-wheel-returnability.html

 

 

Anyways, just my thoughts on some stuff and not saying anyone is doing it wrong or are full of crap.

[69gmachine 15]

Another component of the steering axis is the steering inclination angle (SIA), which on our factory spindle is a rather shallow 8 degrees. I suspect that was done to make steering effort easier on all the non power steering cars which made up the bulk of sales back in the mid to late 60s.

 

For definition purposes, lets call the length of the car the Y axis, the width of the car the X axis and the height of the car the Z axis. Caster is the tilt of the spindle along the Y axis in the Y-Z plane. The SIA is the tilt of the spindle along the X axis in the X-Z plane. Like caster, the greater the SIA angle, the more the steering will want to return to center.

 

The MII spindle increased the SIA to 10 degrees to make the car track straighter at the cost of slightly increased steering effort. IMO the benefit far outweighs the cost for all street, drag race and most other racing applications where power steering pumps are used.

[69gmachine 15]

Another component of the steering axis is the steering inclination angle (SIA), which on our factory spindle is a rather shallow 8 degrees. I suspect that was done to make steering effort easier on all the non power steering cars which made up the bulk of sales back in the mid to late 60s.

 

For definition purposes, lets call the length of the car the Y axis, the width of the car the X axis and the height of the car the Z axis. Caster is the tilt of the spindle along the Y axis in the Y-Z plane. The SIA is the tilt of the spindle along the X axis in the X-Z plane. Like caster, the greater the SIA angle, the more the steering will want to return to center.

 

The MII spindle increased the SIA to 10 degrees to make the car track straighter at the cost of slightly increased steering effort. IMO the benefit far outweighs the cost for all street, drag race and most other racing applications where power steering pumps are used.