So I made this today for my car. Haven't installed it yet, but will be this weekend, most likely. Have a look and tell me what you think! It's adjustable up to about +/- 1/2" from stock (4.25") length for lowered applications. One end is fixed, rotationally, because it's living inside the longer lateral link, whereas the other end is a oiled ball joint because it's a strong way to make the required connection to the beam while also allowing for torsional movement as the suspension cycles. Might be overkill, but for the total cost it just made sense to add it as a feature.



My DIY adjustable link solution

 

What did that cost you to make? Looks like a nice piece.

 

Cost me right around 85-90 USD (including all parts shipped next day air), plus the design time (love being a mechanical designer for a living), and finally the assembly time (there were a few minor modifications to the purchased parts that had to be done). I also chose to buy a 12-ton hydraulic press to put it all together, but that's not directly related to the cost of the linkage, since I didn't already have a press and don't have anywhere to mount a large vise instead.

 

Great job ...hard to find people doing stuff like this, anymore on the org.

 

Thanks man, I love redesigning the crap that is poorly designed by the manufacturer (such as the entire rear suspension linkage setup on the Maxima). I'm probably one of the only people, aside from Nissan's engineers, that has built a kinematic model of the rear suspension geometry for a 5th gen Max, lol. Just so I could truly understand the design flaws & deficiencies in it. IMO, The Scott-Russell linkage was a poor choice by Nissan for a beam-to-body link. It essentially forces the larger bushing (in the lateral link, mounted on a fixed point on the driver's side of the beam) to require lateral movement in order to function "properly," and as a result, the bushing (especially in lowered cars) gets pushed to its absolute physical stress limits and fails, causing all sorts of funky behavior in the rear end. Some of this can be mitigated by using the adjustable link style shown above, but that's really just a stopgap, because all shortening it really does is redirect the angular stresses on the bushing for slightly longer life. Yes, it does ALSO control center line offset of the beam to the body, but it's a ****-poor way to do it. Adjusting the fixed point on the beam is really the key to properly centering the beam. Actually, a different type of linkage altogether is the way to do it. But I digress...

Take a look at the bushing sometime, you will see it basically is just a connected tendon of rubber that runs through the middle of the bushing, top-to-bottom, and allows deflection (measured at maximum 14mm) side-to-side. The required movement of the bushing means you can't use a solid, or even polyurethane bushing replacement. The suspension simply won't work. The mechanics of this setup simply don't allow for a fixed point at each connection pivot of the linkage. The bushing itself requires a redesign for optimal function (which I'm also working on) in this type of linkage (since making a sliding mount on the beam itself might be a tad more difficult).

Keep your eyes peeled within the next month for some updates on this. My ultimate goal is to come up with a combination solution I can sell to the Sentra auto-xers.

 

That's cool do you expect any clunks? using a zerk?

 

At this point in time, no, to answer both questions. The link itself is a more solid connection (albeit, only slightly) than the stock aluminum link with the pressed in rubber bushings. The main advantage I see my design having is the ability to handle a minor amount of torsional misalignment as the suspension cycles up and down (remember, the beam rotates around an axis centered on its mounts on the underside of the body), and that it is length-adjustable to allow the stress to be redirected within the flexible bushing. If anything, I expect this will be equal, if not better, than stock performance of the equivalent part.

As far as greasing is concerned, the ball joint is actually sleeved in oil-embedded bronze, so there really shouldn't be much need to grease it. That said I could always drill a grease port in the end of the ball joint if it appears necessary. The other end is created using solid bronze bushings, and also should not require any lube to function correctly.

 

Pic don't work, curious mind wanted to know!

 

Essentially a similar idea to the original adjustable QT link from a few years back, with a couple twists, yes, pun intended. I'll try to set up an imgur link.

 

Install success! I would say it definitely feels more planted in the rear, but that could be in large part because I replaced the lateral link as well. That said, the old bushings weren't actually in as poor condition as I assumed originally. Either way, the rear end feels better, and definitely less wavy over bumps. Would definitely recommend for the cost and time involved. Before anyone asks, I shortened the link approximately 1/4" from stock, so 4" eye-to-eye, and the beam appears pretty centered to the body. Will find a more level location and take some actual measurements soon.

 

Looks nice! What are the pros and cons to increasing or decreasing length to this link? Centering the beam to the body?

 

There really aren't any cons to this mod, aside from potentially miscalculating the amount of shortening / lengthening necessary to keep the beam centered, and having to pull the whole link off to readjust it. The pros are that AT a lowered ride height, the resting position (meaning on level ground or parked, not accelerating or decelerating) of the individual links is able to be more closely matched to the distance between the fixed points on the beam. In fact, it can be matched exactly.

But the reality is, the center of the beam itself (relative to the body) is dictated by the relationship between the fixed point on the body (the small bushing on the lateral link), the angle of the lateral link in relation to the beam (at any point in its allowable movement), and the length of the connecting rod (since the connecting rod is rigidly attached inside the lateral link AND the beam). So you can start to see how a change in any one of the aforementioned variables (during a suspension cycle) actually shifts the center point away from true center. Hence why I said it was a ****-poor way to design the linkage. No matter how you slice it, the rear suspension has a small inherent bias towards one side. It's one of those "good enough" type of engineering designs, where, yes, for 95-98% of your target demographic, it will be "good enough," even if it's FAR from optimal. I hate this kind of mentality, but I'd imagine you can't really get around it in mass-market production.

 

So how do I go about getting one of these?☺

 

great work man ! glad to see this work as others have said, re-engineering isn't really going on for our calls much any more. since your so mechanical , what do you see this bar doing? still can't picture what it does.. if anything though you might like figuring this out, basically same area. it says it has 4 connection points, but the picture hides 2 of them.

http://ultraracing.my/ecatalog/index...-member-brace/