3 link rear suspension

[marty69212]

i dont know a thing about rear suspension geometry, but im looking for a rear suspension for my 1969 camaro pro-touring project... my question is .. if i ised like a 3 link with a watts link, why couldnt the
top center link be directed rearward into the trunk , instead of taking up rear seat space? is this even a valid idea... like i said i have no clue what im doin, but would that work?

[parsonsj]

The thing you have to consider is what does that do to your IC (instant center). IC is the imaginary point where the upper and lower control arms converge (in side view), and can be thought of as the point about which your rear-end housing rotates. Anti-squat is derived from your IC.

Putting the upper control arm "backwards" ruins that concept. There is no IC, since the control arms don't converge in side view because the upper control radius is not inside the lower control arm radius.

Not good, but I'm caught a bit short on figuring out the math. Perhaps Norm or Marcus or Mike will weigh-in (or even Katz!).

jp

[Norm Peterson]

Probably not very well.

Whatever anti-squat you dialed in at static ride height would go away very quickly (IOW, with very little suspension movement into bump) - probably somewhat faster than 50% per inch, and the IC will end up being several feet behind the rear bumper. You'd even notice it in normal driving, as I think you could get it to squat worse than a FWD econobox without having to try very hard (and I think it would ride a bit more harshly over bumps as well).

Physically, it would be competing for space with things like the gas tank and perhaps the Watts link components and support structure.

I'd think a better compromise would be to locate the axle side pivot of the 3rd link above and slightly behind the axle centerline in order to get somewhere near a reasonable length without having to infringe too much on rear seat space. You might have to have a 'bent' or 'S'-shaped upper link to minimize other sheetmetal clearance issues, but there's at least one available 3-link package that does precisely that (its 3rd link is somewhat odd-looking, and heavier than a more normal link, but it does its job while satisfying a no-sheetmetal-modification restriction).

Are you really trying to seat a third passenger back there?


Norm

[parsonsj]

Are you really trying to seat a third passenger back there?That's the real question. If you run bucket-style rear seats, you'll have room for the upper control arm.

jp

[Jimmy Sean]

Probably not very well.

You might have to have a 'bent' or 'S'-shaped upper link to minimize other sheetmetal clearance issues, but there's at least one available 3-link package that does precisely that (its 3rd link is somewhat odd-looking, and heavier than a more normal link, but it does its job while satisfying a no-sheetmetal-modification restriction).

Norm

I would like to look at this could you share who has this available?

[Norm Peterson]

http://www.gmachineracing.com/mustang3link.html

More discussion here (http://forums.corner-carvers.com/showthread.php?t=34046).


Norm

[Marcus SC&C]

A rear facing upper link would turn the axle housing into the "propeller" of a watts link in side view. The IC location and pinion angle change would both by funky. The upper link would also have to anchor where chassis are traditionally low load requiring some creative reinforcement,especially on a unibody car. You can do several things to make a 3 link easier to package. Norm mentioned mounting the rear pickup of the 3rd link behind the centerline of the axle to get a longer upper link without intruding into the cabin. Although not technically "ideal" we`ve used this with great sucess in the past. You can also offset the mount to the pass. side,which can be a help in compensating for axle torque. This can also let you lower the upper part of the mount for more floor clearance. Your best bet is to do a lot of research before you start cutting and welding. There are many conflicting opinions on how 3 links can and should be set up (possibly the understatement of the year). Mark SC&C

[jason@gmachine]

Hello everyone!

We had this problem with a build of a original 68' where the customer did not want to cut the floor. Our solution was to design a upper link that fit the body and provided good geometry. Now, cutting the floor would have given us better geometry but that was out of the question for the customer. We have also thrown around the idea of a Z link setup like the one you mentioned above but we only came up with average results.

Here is the link we created.

https://static1.pt-content.com/images/noimg.gif

https://static1.pt-content.com/images/noimg.gif

its made of 3/16" 4130 and uses Chromoly heims and Light Racing 4140 recievers. TIG welded.

Jason