Daze wrote:

Thit is well built.  how much does it weigh?

 

Probably alot more than the original. I have alot more brackets, fitting, and seam welding to go. I'll weigh the whole car at the end.

I could probably also shave some weight here and there on the lower controls. I made them telescope, and just tacked them, as measuring the original leaf and pirch didn't seem very accurate. Once I know it's straight for sure, then I can go to town on refining it.

I wanted to keep the original frame rails, which caused an unbelievable headache. I also wanted more than two inches of compression. The original rails are about 3" in front of the axle. So the uppers are behind the axles. The lowers are forward - mad caster. But putting the upper above the axle would have left me with very little travel. I'm in PA and the roads are terrible here.

The car is a 78 trans am. The diff and axles, which I'm hoping to test fit next week, are 04 svt mustang with G force axles.

It's really complex to describe it all. I also wanted to fit the original 15x8 snowflake wheels. Which I think I'm getting away with. Also factory rear rotors.

The shocks and springs I'm hoping to mount in the trunk horizontal - pushrods. I also grabbed an electronic rear steering rack from a 300zx, I may implement.

Has anyone ever seen a lower ball joint mounted at anything other than vertical?

As in both the knuckle and the lower controll arm are designed with an angle, and the spring /bump force is no longer solely a tension/compression load on the ball joint, but now also partially shear.

Problem is, my rear bearing housing section of the rear knuckle is 5" in diameter, and I want to use 15 wheels. This leaves only about 4" height for a lower ball joint, which K6293 is about 4.6" tall.

Should I move the ball joint inboard like poor kingpin angle?
Should I move the ball joint forward like poor caster?
Should I use a spherical with possibly an axial load ration some 20% of the radial?

Thoughts? I'm way over my head here.

Thanks Ralphy.

its proving to be very difficult. My nam is Jon btw.

the explorer cvs are basically not usable without an extreme amount of effort. They are really, really non servicable in a way that would take destructive methods to remove the outter cv. Using four explorer cvs to assemble two may be an option, and modding the outter and inner cvs to run a porsche 930 or 934 would possibly be a better option. But right now I'm considering the explorer cv research project a small defeat- about $80

On the Z-bar, like I said before, the cobra cross-axis don't really have a comfortable amount of non-radial movement. There is the option to mill a new insert for a com12 with more angle. Which is looking like on of the two most plausible solutions.
  I had considered deviating the forward and horizontal bearing into two seperate bearings, but this caused a series of issues that amounted to it being non-feasible. Some of these problems included the bearings be on the same axis for the suspension to be safe, and problems with keeping the arms not twisting due to the fact that springs, shocks, and sway bars must be mounted to them.

Second most plausible solution is to accept defeat on having tuning options in the forward instant center and run a trailing arm with two inboard links for camber and maintain the toe link. This would be somewhat of an odd design, and one clearly designed around my rear frame limitations. Kind of like a C3 corvette with two additional hinges in the trailing arm to adjust toe-in seperatly from the trailing arm.

This may
This maybe the sort of thing, 

Ok, thanks.

Possibly I will join the cobra forum, but I don't have a cobra. That doesn't mean they don't have good info though right.

i have cobra knuckles; Mustang svt Cobra 99-04 IRS


most cobra kit guys are using these; thunderbird, cougar, lincoln mk8 knuckles(I have these also)

Sorry about the delay. I'm trying to use the cobra knuckle.

keep in mind the cross axis joints of the cobra knuckle have about 12 degree of out of position movement. This would give me about 5" of rear travel with the design I questioned above. This isn't enough for me I feel, and I'm looking into fitting a com12 spherical housing as a joint replacement.

im also not happy with the flange diameter of the cobra hub as my car is a GM.

ive obtained a single ford explorer hub and rear cv for fitment tests - hoping to combine them with the cobra knuckle, cv bar shaft, and inner 31spl cvs.

the explorer uses a much larger bearing, and the outter cv stub seems to have more splined area and less threaded area. Right now, for the life of me I can't seperate the explorer outter cv from the shaft to see if the inner spline dimensions are the same as the cobra. The hub/outter cv are not the same 28 vs 29.

so, that's where I'm at.

thanks.

I'm going to read up there in the linked thread. Thank you. Right now I'm waiting on some explorer IRS parts for R&D. I'm looking at this design as I do not really have any room for a forward upper link without major surgery.

I have some questions on a z-bar design, or longitudal watts link.

Is there a thread here regarding the anti-squat or brake hop geometry of this type of suspension? Can you link me there or give me a search clue?

what is the official name of this type of of link system? Dirt modifieds seem to call it a Z-bar. I have also found it referd to as a longitudal watts link.

Think C4 corvette, but with the upper link facing towards the rear of the car and mounting to the chassis back there.

What are the pros and cons?

Thanks.



 

Thanks Tyrellracing! I couldn't ask for anything more in a response!

I took one manual machining course and I would like to go back for advanced manual machining and something that would smarten me up towards heat-treating. I wish I had your knowledge and experience - I'm truly impressed!

Your response shed a lot of light and is giving some better direction. It's greatly appreciated.

Thank you again.

Daze wrote:

First let me start by saying welcome to the forum!!!  Just for my own curiosity, directed here from where?  As the admin I am always curious how people find the forum.  The info helps me to improve forum exposure.

Thanks. I was actually at the chat section of ClubS12.org, which is a site fore Nissan S12s, which is another project car I have(R200 semi trailing arm IRS), when another member posted up the link to here While I was picking their brains for possible hub doners.

Daze wrote:

There are only three options I see for the bolt pattern the first would be to use a pattern changing ring and the second would be to find a hub with the correct spacing for another application and make it work.  obviously if you can make option two work you will be much better off, but finding that "magic part"  may take some doing.  Third would be to change the front wheel pattern to match the rear.  With the IRS parts being more exotic it is often times easier to modify the front hub to match the rear.

 I am considering redrilling the fronts for a ford 4.5", but its not really what I want to do. The pattern changing ring isn't really an option for me as; 1 - I'm a little looney and already mill hub centric rings so a wheel mounts positively to the hubs(though its somewhat overkill), and 2 - the ford IRS assembly is .5" narrower than the stock Firebird axle(hub to hub), and I don't want to go wider than the stock axle width.

Daze wrote:

The 10mm bolts you speak of how many are there??  Just like with axle splines and thread count, quantity is more important than size.  Not being an engineer I am not sure the math or how it exactly works but I know several small bolts working together can be much stronger than one big one.

 The Mustang is a dual A. They don't have ball joints but more like spherical bearings, and these 10mm studs are the bolts that pass through - so yes there's two 10mm studs and the toe link - that's about all the locate