512_Rear 3-Link CAD or "Todays Paper Dolls"

3d'ish version of my drawn up 3-link for my 67 mustang track car. Trailing link bars will be double shear mounted at frame and upper 3rd link mount, and unfortunately only single shear at the lower axle mount. Also, drawing does not show correct shock angle - too busy with real work to draw the shock with spherical bearings so the shock is limited in motion.

Trailing arms and upper 3rd link are 32" long. Ride height as drawn is 1.5" lower than current. Springs are 10" long, 275#. Obviously no spring damping is applied in this simulation.

Rod ends are drawn with 'fingers' to aid in monitoring the SVSAL. The thin horizontal line is the "estimated" CG height of 18.75" and the angled line from the rear contact patch to the intersection of the front wheel center and CG height help give me an idea of where the Anti-Squat % is. The vertical line through the center of the wheel allows me to see the front/back movement as the suspension travels through its motions.

Category:

Autos & Vehicles

Tags:

• 512
• Mustang
• Paper
• Dolls
• 3-link
• suspension
• road
• race
• car
• inventor
• auto
• desk
• CAD
• racing
• mustang 3 link

[darsh67stang]

I've got a 67 coupe that I'm wanting to do a rear suspension upgrade to. Can you point me in any direction as to where i can find some detailed specs on building one? I've seen all the kits that are available from several companies, but i really want to take the pride in building my own.

[jsr512]

The best thing I can do is point you to a great book. It's called "Race Car Vehicle Dynamics" by William and Douglas Milliken. It's a bit expensive, perhaps you can find a used copy on Amazon or something. It's a pretty serious book, a lot of math. There are a few decisions and compromises to make - how much anti-squat do you need? How long can you get your SVSA? Where should your Instant Center be? All of this is explained in this book so you can make the decisions for your design.

[jsr512]

I'm very happy with the results from my design. It works much much better than the stock leaf spring setup. It helped me considerably to draw it up in a CAD program so that I could visualize what was happening as the parts moved together. You'll notice that the trailing arms all have thin fingers on them - so I can see where they intersect which gives me a visual cue to where the Instant Center is. Also, the 100% anti-squat line (from the rear tire contact patch to the center of the...

[jsr512]

@jsr512 center of the front tire at the center of gravity is drawn in. This allows me to see how much anti squat is in the design. If the Instant center is at this line, that is 100% anti squat. If the instant center is below the line, then this is less than 100% anti squat. And if the instant center is above the line, the anti squat is more than 100%. The stock setup with leaf springs was greater than 200% anti squat!

[brian357]

Do you have anymore info on this? I am doing a similar setup on my 66'.

[jsr512]

@brian357 Hey Brian. I'm sorry I missed this question somehow. If you want, sent me an email here via youtube and I'll give you my number and email. I'd be happy to take a look at what you have so far, and also explain my design to you. Hope the car is coming together well.

[jsr512]

The individual shock parts are drawn in inventor, less the springs.  The assy is brought into the dynamic simulation application (of inventor) where the coil spring is added by: Insert Joint -> spring / damper / Jack, and selecting the coil spring properties.

[HilariousShortFilms]

how do u get the springs to move? do u use coil