Thread: 3 Link Suspenson Question

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I have a sports car project that's still in the planning stages. It's an older kit car that uses Mustang II rear leaf springs. I would like to go with something more adjustable and better suited to handling. I've been looking at both the torque arm and 3 link. The torque arm looks good, but the driveshaft is pretty short and I don't think the arm will be long enough to keep brake hop down. For that reason I'm looking at a 3 link. Most sources agree that they can be set up for some anti squat without inducing bad roll steer characteristics.

I've studied everything I can find, both in books and online, and see some sources recommending the upper link be 70% as long as the lowers while others don't mention it at all.

What is the reason for this length difference? I would think you would want them as close to the same length as possible to keep pinion angle from changing.

I had a 3 link in my Monza pro stock car-----------upper link wasn't that long, altho I did have 3 different ones and 3 different sets of mounting holes along with being able to shim/adjust side to side about 5 inches---needed side to side so the car would go straight-----took a while to get it right with spring rates,etc but was great for drag racing---wouldn't want to deal with one for a sports car type deal

With work on some careful design, the 3 link works quite well road racing.... It does take a lot of testing and adjustment to get it right. Back in the late 70's some of the IMSA teams (GT and GT/O) used it, primarily the BMW team that Haywood drove for... Bolus and Snopes also had one on a Mustang (now it would be a GT-3) car, got to get a bit of first hand experience with that one. With reasonable good mechanical drafting skills you can draw it out and plot the movement, which will answer your question on the length of the upper link. The shorter upper sacrifices pinion angle, done correctly less then 1 degree of change, which can actually help acceleration out of a corner, in favor of anti-dive for braking and anti-squat on acceleration.

Most people don't comprehend that the rear end doesn't move up and down---------the rest of the car does------and the rear end stays on the ground

If handling was one of the main points of my build, I'd probably be lookin' at IRS. Mild motor, Jaguar....strong motor, Viper or C4-C6 Corvette.
C4 Corvette Complete Rear Suspension Rotor to Rotor 1988 1996 | eBay

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Originally Posted by techinspector1

If handling was one of the main points of my build, I'd probably be lookin' at IRS. Mild motor, Jaguar....strong motor, Viper or C4-C6 Corvette.
C4 Corvette Complete Rear Suspension Rotor to Rotor 1988 1996 | eBay

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Absolutely!!!! Once you've raced/aggressively driven a car with IRS, it's really tough to look at a solid rear axle for anything other then a drag car!!!!

I had considered an IRS, but I was trying to keep this build fairly simple and inexpensive ( I know that's laughable). There aren't many Vipers or Vettes in the salvage yards around here. I might find a T-Bird or Mustang IRS. The engine I'm planning on using is a 383 stroker that I already have sitting in the shop.

Another factor is that I wasn't planning on pulling the body if I could get away with it. The link type solid axle setup could use the existing leaf spring mounts on the chassis and all I would need to add is the upper mount. It might not work out that way, though.

If I'm forced to pull the body, I will take another look at an IRS. I'm certainly not going to argue that it's not better for road holding.