[pigman]

im building up my 70 mustang, and i want to know what you guys think for a rear suspension. It's not really a drag car, I would rather have it handle really well on the street. Maybe do some slalom with it, i don't know. But i want it geared more to cornering then straight line.

It has a Ford 9" rear.

Is a 4-link good for this, or is that more for straight line?

Thanks,
Mike

[johnsongrass1]

While 4 links are quite popular, a 2/3 link will give the same results without the loose roll steer. Roll steer can be an affective tool if used and driven properly.

[BillyShope]

In agreement with the KISS principle, I'd use that which is so successful at your local roundy-round track: 3link with Panhard. If you merely copied the geometry of the 2005 Mustang, you couldn't go too far wrong. Personally, I'd want to offset the upper link to the right to gain cancelation of the driveshaft torque, but that's just my personal preference.

You certainly wouldn't want the dragstrip 4link, with solid attachment to the axle housing, as this causes binding during cornering (unless the links are parallel, as viewed from the side). You could go to a triangulated 4link, but that's a lot of work and really offers no advantage over the 3link and Panhard (the KISS principle again). If you're considering some kind of kit, I suppose you could use Morrison's 4bar. Most install this with the bars parallel to the ground, which results in a lot of squat during launch, but, if you angle them up at a tangent equal to the CG height divided by the wheelbase, you can eliminate the squat. And, of course, the parallel arrangement also avoids binding.

But, again, I'd follow the lead of the Ford design team and use a 3link with Panhard.

[OneMoreTime]

That is the way I am going on my project..the lower links are outboard about where the leaf springs used to be on my housing and the upper link is mounted on the right side of the punkin housing (ford 9")

Panhard bar will run from right side frame to left side of the axle..I have not as yet exactly worked out all the dimensions for all of it but that is the way it will be..

Probably will not know for sure how it will handle till I get a chance to try it out..

I may and expect to have to change the springs once or twice and fiddle with front to rear bias with sway bars (relative stiffness front to rear) and make adjustments to shock valving..just how much kinda depends on how bad I want get around an autocross event..

OMT

[pigman]

very good info, thanks all

while were on the topic, what about front.. I mean there is the ever popular mustang 2, or other a-arm suspension, but does anybody make ifs kits with other designs? I hear through the grapevine that double wishbone suspension is really widely used in racing, because it can be tuned so well, and works better during cornering

know of any better kits, or donor cars with better front ends?

[OneMoreTime]

they have quite a bit of interesting books and software for chassis design..I suggest pay the money read the books..front and rear chassis design is done as one piece of work to get "hopefully" the front end working with the back end...

Study anything the circle track guys do as they go around corners as well..tho only left..

Go to This place and read all the online tech articles..then you will have a good start on building your chassis in a way that works..

OMT

[Triaged]

I think the 3-link is the best option....

However the 3rd gen f-body torque arm type suspension is very low profile and a good choice if you have to make it fit under a floor board or back seat.

The 'truck arm' suspensions that NASCAR uses are nice because it is harder to screw them up (IMO). The downside is that the suspension itself acts like an anti-roll bar and the only way to change its stiffness is to change out the trailing arms. It is also quite bulky to fit under a car with full exhaust but it should also fit under the floor boards.

I am still working on a calculator for 3-link + Panhard suspensions.
This is a BETA version:
http://home.earthlink.net/~triaged/F...kV1.0aBETA.zip

I have one for a triangulated 4-link that is in its 3rd version already
http://home.earthlink.net/~triaged/F...arLinkV3.0.zip

I have recently started playing with LabView and I might make future releases of the calculators stand alone programs (right now it is an excel based spreadsheet file and if you don't have excel you are out of luck). I would however most likely have to start charging for the calculator because LabView costs a few $1000 if you want to use it to make stand alone *.exe programs

[smallblocker2]

I agree with Triaged as to the third and forth gen F-body 3 link torque arm panhard is the way to go. For solid axle rear nothing beats it, if you want to pull skid G's. The torque arm is very effective in transfering weight for 1/4 milers as well. For front , well nothing beats SLA dub. A-arm.

[johnsongrass1]

Torque arms unload the springs unless you move them above the axle. One in front and one behind can help. A 90/10 shock on the torque arm mount slows down the unloading, Making the car less violent.

[Triaged]

Originally Posted by johnsongrass1

Torque arms unload the springs unless you move them above the axle. One in front and one behind can help. A 90/10 shock on the torque arm mount slows down the unloading, Making the car less violent.

You lost me there. I don't see how moving the torque arm up or down would do anything to change the geometry. It makes no difference where is is located on the axle only where the chassis mount is located (that comment is going to confuse some of you isn't it?).

I have always considered the torque arm suspension as a special case of a 3-link. The torque arm can be considered as part of the axle housing. The sliding mount at the trans output can be 'replaced' with a vertical link of infinite length. What this does is put the IC at the length of the torque arm and the height where the lower links would intersect a vertical line through the torque arm mount. The length of the IC would never really change and the change in height would depend on the length of the links. To a point the height of the torque arm chassis mount would make no difference. Is there a flaw in this way of looking at it?

Are you talking about too much anti-squat/dive when you talk about unloading the springs? That can all be taken care of with the height of the links and the length of the torque arm....or are you talking about having too short of an IC length?

[pigman]

OK, so I have been looking around for kits and setups i can use to achieve something like this. It has been hard to find any 3 link setups.

Here are my options:

For the frame im looking at Chris Alston Chassisworks products, looks pretty nice, and the prices are competitive:
Frame

It directly takes any of their components so:
I can use their Front IFS, pre welded to the frame

AND for the rear:
They have a Billet aluminum triangulated 4-link. From what i understand the triangulated system will not bind? And also, with a triangulated system, will i be able to set up both anti-squat and roll-under-steer properly, i understand that it is not possible with a parallel 4-link, but with triangulated it is ok?

I want to stick with the Chris Alston setup if i Can, because i can get all the brackets pre fabricated, and attached to the frame, alot easier to guarantee the setup, and they should have a frame that will slip right into my body

If the triangulated 4-link is no good i could go with:

Factory Five Racing 3-link:
3-link

Let me know what you think, post links to your favorite kits as well
Mike

[johnsongrass1]

Remember I'm not a chassis guy, I do engines but let me try.

The chassis or trans mount, chassis mount in my experiance, moving it closer to the front tires will provide more front lift and transfer weight to the back to increase forward bite while on the gas. Rolling out of the throttle will pick up the rear end making it loose going in the apex. Putting a load timing device( a shock and spring) between the torque arm mount and chassis gives you the ability to adjust when the rear axle load changes and how much. Moving the axle mount further from the roll center of the axle increases the leverage applied to the chassis mount. That only changes the fifth coil(as dirt guy's call it)rating. If it were all bars with no coil over, the car would react very fast and very violently making being smooth (the best way around a closed course) very difficult when traction is high. As on pavement.

A 2/3 link works the same with the pull bar located above instead of below the rear. While pull bars(the upper link) are called such, the torque arm could be called a "push bar".

Does that make sense?

[trees]

Pigman, check out the 66 Mustang Suspension thread above. I have posted some pics of the front suspension and R&P steering (Chris Alston stuff) Ill keep you posted on what he is doing to the rear next, if you desire. He takes the car to a road course near Nashville, Tenn. for testing and competition

Trees