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I thought I'd share my latest project with you guys, A revised version of a 4 link a designed and built several years ago.
After getting my turbo setup done last year I was contemplating swapping out the gears and G80 differential in the 14 bolt that was in the truck. Like I always do, I convinced myself that it would be cheaper if I just sold my current axle and 4 link started over fresh. Also, I wanted to build a kit that I could replicated in the future much easier than the first design.
For the axle, I ended up going with a Moser M9 with 35 spline axles, a Truetrac, and 3.70 gears. Within 20 minutes of driving a realized how much better the Trutrac was than the good ol' G80. I was almost turning 3000 rpm on the highway at 80mph, which was a little excessive in my mind. The new gears brought it down closer to 2600 which was a plus. One thing I didn't take into account was how I was going to mate my current Stoptech brake setup to the 9" housing ends. I ended up machining an adapter that allowed me to bolt the factory Silverado E-brake/Caliper bracket to a Big Ford Gran Torino axle housing end. The adapter holds in the axle bearings and provides a mounting surface for the truck brake brackets.
With the axle assembly here and done, I started looking over my previous 4 link design. The geometry itself was great and had worked well for the previous 10k miles. I focused on redesigning for easier manufacturablility and assembly. Version 1.0 was drawn mostly in Mastercam so it was a fairly crude model (mostly 2D sketches.) Shortly after I completed that I started using Solidworks at work and became hooked. I got a laptop so I could start modeling at home as well as work, and started modeling up 4 link version 2.0. With the help of some kick *** friends that are more experienced than I am with engineering and Solidworks, we ran an FEA analysis on several versions of the Watts cross member and dialed in the design.
I machined a revised pivot and pivot brace and got started mocking up the new rear in the truck.
One thing that I found to be really cool was how well a suburban rear sway bar fits a Moser M9, it's like the were made for eachother!
Once everything checked out, I pulled it all apart, welded it up, and sent it off to to be powder coated. I got everything assembled and torqued one last time, ran some brake lines, double checked everything, and took it for a test drive. Being that the geometry is all very similar, it handles much like it did before. The biggest improvement definitely was the Trutrac, it feels much more stable and predictable under power.
It was a fun build, but I'm glad its on the road again. Thanks for checking out my project. Time to turn up the boost!
How much weight does the watts link crossmember add?
I presume the revision of moving the bell crank off the axle to the chassis was for roll center adjustments? I see the adjust-ability of the bell crank but the link mounts on the axle seem stationary. Does the relationship of the link angles affect functionality as the bell crank is moved up/down?
How much weight does the watts link crossmember add?
I presume the revision of moving the bell crank off the axle to the chassis was for roll center adjustments? I see the adjust-ability of the bell crank but the link mounts on the axle seem stationary. Does the relationship of the link angles affect functionality as the bell crank is moved up/down?
The cross member and watts links weigh 23 lbs and the 4 link bars weigh 48 lbs. I didn't get a chance to weigh my axle, but I'm fairly certain its lighter than the 14 bolt I had in there previously. I should have weighed the leaf springs before I got rid of them to compare total total weight change. Several years ago I weighed the truck with the 14 bolt, leafs, big brakes, wheels, and stereo with a half tank and it was just shy of 4600lbs. I'll have to weigh it again soon to compare.
I put the adjustment in the cross member so that even if ride height changed the pivot point could be adjusted to stay as close to the center line of the axle as possible at half travel. I initially set it up for the links to be as close to parallel to each other as possible at half travel which offers the least amount of side to side movement, but have been tweaking the ride height and haven't got the Watts re-adjusted yet. It could probably go up a notch or two. Definitely overkill for my truck, but then again so is a lot of the stuff we do lol.
Thanks man, I have done any racing yet, but I’d like to in the future. As much fun as the turbo 4.8 is on the street, it doesn’t seem ideal for something like auto x with a lot of low speed and quick throttle response. I’d still love to give it a try though. I may get a set of drag radials to see how it doesn’t on the strip as well.
Your right on the tires, I’m running a 315/35/20 continental extreme-contact sport on a 20x11 in the rear.
Your right on the tires, I’m running a 315/35/20 continental extreme-contact sport on a 20x11 in the rear.
Is there any chance that tire could fit up front on a 4" drop with stiff suspension without cutting the fender openings bigger? I am trying to find something wider that a 295/45/18 with a 28-29" diameter. If I could run square 315's on the same offset wheel so they could be rotated, that would be awesome.
How is the balance on yours with the 275 up front? Does it want to push the front end if you try to take a corner too hard?
03-18-2018, 11:12 AM
2005 turbo silverado 4 link version 2.0
