Sorry,
You did ask that a while ago didn't you. Arning did that with the 427 Cobra or the Super Cobra back in the day. However, I think you would need a good computer to get the math right. My thought is that for a do it yourselfer (me) it needs to be adjustable. Because I have no idea where the geometry would work right. Check out Arnings design below.



Twin Turbo at Vettemod has or is trying to copy it.


http://www.digitalcorvettes.com/forums/showthread.php?t=83379

Let me add this Pier's design, the C3 red Vette posted here. Has his own design and the amount of steer he has tuned in is very little. His words were something to the effect, it gets way wild with to much.


Why can't you do your camber toe rods like this?


OK, so in your mind? If this setup rocks fore and aft, what does the hub do? Right, it stays straight, nothing but no toe the rods are parallel. Now what if you widen the inner mounts like you need, to clear your rotors? Hmmm, now your hubs turn left and right if you move them for and aft. Use the camber toe rods like this Guldstrand and use the trailing links like the Arning (Duane) set up. You can tailor the amount of steer by how far you move the toe/camber inner points out. Or make one parallel to the half shaft and the other angled and you will get better control of toe motion. Remember Duane's trailing links move the wheel back during jounce and forward at rebound.

This IRS stuff is a gas. Running a solid axle vs. IRS is so foreign to each other. Solid axles move in two dimensions an IRS is three dimension control. Should we even be fooling with these things?

Oh another thing C4 vs. Pier's design. It seems to me the C4 having a longer toe rod vs. the half shaft causes the rears to toe in regardless of jounce or rebound. Pier made his toe rod equal length to the half shaft. He then moves the outer end up or down to add or remove roll-steer. This makes the rears turn in the same direction when the body rolls.

Last edited by Daze (11/01/2011 8:08 am)

Daze, is the drawing a different Arning designed system?

The Arning designe I have in my files is totaly different then the one in the drawing or above it in the picture.
Arning located the rear trailing arm to the top of the hub and the front to the bottom of it. In motion these act like a watts linkage and therefore the need for a heim-joint on the LCA inner pivot. Sure the heim-joint also aids in adjusting toe but this could also be done by shims (cheaper). I m sure that the watts linkage that is in Arnings design is there to center the wheel in his full travel.
With that said, the above shown systems have nothing to do with such a future and the LCA heim jaoint helps only in toe adjustments.

That how I see it when looking to the pics and drawings. Correct me if I'm wrong please!

Mustsed

BTW, to get back to the orginal post!

How areyou going to steer the rear wheels?

In very slow motion they have to turn opposite the front wheels tu make turning radius smaller but at higher speeds they have to turn same with the front wheels to chage a lane for example - how will this be controlled at what speed and how much rear wheel turn for how much front wheel turn?

I know a few guys overhere that have off-road cars with fron taxles in the front and in the rear with reverse cut ring&pinion gears. During offroad use it is beautifull but if you gain speed it turns faster then you can imagine and the results are not that funny anymore.

Mustsed

Ralphy, If they turn in the same direction, you wouldn't be able to make a U turn but go sideways. There has to be a changeover from slow speed (opposite turning front&rear wheels) to higher speed (both wheels turn into same direction)!

If they only turn the wheels on higher speed driving and keep them streight locked in slow speeds, then it is useless IMHO.

Mustsed

Last edited by Mustsed (11/01/2011 9:54 am)

Mustsed, you have missed some good debates and brainstorming on this concept.  See what happens when you leave us for a few months

The concept is really kind of simple, and was originated by Klaus Arning.  If you look at the Arning IRS it has built in rear steer. 

For lack of an easier way to explain it, the for and aft trailing arms are set at different angles and have different arcs, coupled with the single pivot at the differential to allow the rear wheels to toe in and out during suspension travel.  It is not rear steer in the sense that the rear wheels are making huge turning movements, like on a rock crawler.  As ralphy said it is only a degree or two but is enough to improve handling and cornering.  take a look at this video it will explain it better than I can.
http://www.mustangirs.com/?video=irs_classic_full

OK not that one this one

http://www.mustangirs.com/?video=irs_new_full

Last edited by Daze (11/01/2011 11:43 am)

But I would need some really small airbags to go were those coil overs are haha.

Hi everybody,

First of all I would like to mention that "Steer" is something different for me then a degree of toe-in or toe-out. The germans had a bunch of cars that should get rear steering axles and that was what I am refering to.  Sorry for the mis-understanding!

On the other way I can see that there is a minimal "steer" in the back but how much will it effect a normal driven classic car? On the other hand, an IRS by itself is an update in driving comfort and performance increase more than one can imagine. After driving the '67 Mustang I installed the first Jaguar IRS into, I tought it is a totally different car and has nothing to do with the old Mustang we used to drive.
My own '67 has all roller front end, roller 5.0 engine, AOD tranny, PS gear box out of a New car, performance suspension and now goes in a Jaguar IRS. I thing after all this there shouldn't be the need for toe change in the back in a 44b year old Mustang IMHO. Before the IRS the Mustang was a blast to drive and it can only become better with IRS. There has to be an end sometime on the modification list I wrote 20 years ago ;-))))))


Mustsed

Mustsed wrote:

First of all I would like to mention that "Steer" is something different for me then a degree of toe-in or toe-out. The germans had a bunch of cars that should get rear steering axles and that was what I am referring to.  Sorry for the mis-understanding!

I think you are absolutely correct "steer" is one of those words that congers up other ideas, but for lack of a better term I am not sure what to call it.  hmmmmmm ideas???

Mustsed wrote:

On the other way I can see that there is a minimal "steer" in the back but how much will it effect a normal driven classic car?

I think something that was said in the video I linked gives you an idea of how much this could help.  In the video Duane talked about how a live axle also moves from side to side and and it is this motion that creates the need for slight steering corrections as you go down the highway to maintain a strait line.  If uncontrolled unintended side to side motion causes  noticeable car movement that requires steering corrections can you imagine how  those same "steering" effects from the rear end could benefit over all steering if it was controlled and consistent and working with the front steering, in other words requiring significant suspension input to actuate like when cornering?

Mustsed wrote:

Before the IRS the Mustang was a blast to drive and it can only become better with IRS. There has to be an end sometime on the modification list I wrote 20 years ago ;-))))))

And that right there is the real issue, how much is to much and at what point do the effects of the improvements we are adding become negligible.  This is such a great question that I have started a new thread so we can discuss it.

Last edited by Daze (11/02/2011 1:37 pm)