Complete redesign of rear suspension

I purchased some software from Speed-Wiz that analyzes suspension as well as a thousand other cool things about my race car and discovered some good things and some bad things. The good thing is that my front roll center (the point in space where the front of the car rotates when leaning into a turn) is 3" off the ground. The bad news is that my rear roll center is 14" from the ground. It's common practice to have the rear roll center a little higher than the front roll center, but an 11" difference is silly. There was no way to correct this using the triangulated 4 link suspension I had and I would never be happy leaving it as it was, so I performed massive surgery on the rear suspension.  I decided to go with a 3 link suspension and use a Woblink for locating the suspension side to side. A 3 link has the benefit of having no bind through the range of suspension travel plus I can use all the bars and rod ends I already had. The Woblink is unusual but has proven effective on live axle cars in road racing and it provides a lower roll center than either a Panhard or Watts linkage can provide. There is a video at the bottom of the page showing it in action as well as a link to the Speed-Wiz website.

Here is the single top link with my newly fabricated front and rear brackets.

I decided to make new lower front brackets and move the holes farther forward, which adds length to the bars and reduces the amount that the axle moves in a forward and back direction while going through it's range of motion.

The new brackets, with the holes drilled in an arc that allows me to change bar location without having to change it's length

All three new suspension mounts welded into place.

This is the beginning of the Woblink. It is the bracket that hols the long link to the axle, and you can see it in the next picture, bolted to the axle flange.

The two brackets that hold the Woblink arms to the axle.

This is the Woblink pivot, also called a football. The top rod end attaches to the short bar going to the axle housing, the middle rod end goes to the long bar. I made the bottom pivot from thick wall tubing and added hardened steel bushings and a grease fitting. This pivot takes the side to side force of the rear suspension and becomes the roll center.

Here is the Woblink bolted to the diff.

I built the suuport that holds the Woblink in place out of 3/16" cold rolled steel plate. After this picture was taken, I removed considerably more material to take some weight out of it.

Here it is painted and installed on the car.

Note the bars bolted to the bottom of the support. They run forward under the diff and to the frame of the car, providing some stiffness to the support,

 Video of Woblink in action
Speed-Wiz website

EFI Problems sorted

Project update: anybody who has seen the car run knows it smokes pretty badly. The stock computer was not set-up to run the 24lb injectors I have and fuel was dumping into the cylinders. I got a custom tune using a product called Tweecer and the problem didn't go away. The Tweecer software shows real time readings of all engine sensors and my MAF sensor appeared to be faulty, so I bought a new one :(  The new one showed the same low voltage and a tech at Painless (wiring harness manufacturer) said I have a bad ground.

 I re-did all the ground connections, going as far as welding bolts to the frame that are used to attach the ground straps. Still no changes in the MAF readings so I put a voltmeter on it and lo and behold, the voltage was exactly what it's supposed to be. It turns out that I got a bad version of the Tweecer software and once that was corrected, the voltage displayed correctly. Still, the engine smoked. In the process of all these checks, I discovered that I had done my initial ignition advance based on the wrong marking on the timing tab and it was around 20 degrees too advanced. Corrected that and it ran 100% better but still smoked. I assumed that it was just a bunch of oil/gas coating the inside of the exhaust and would eventually burn off. Then I noticed that my air charge temperature reading was -20 C. I was not running the car outside so how could it be -20 C degrees? I replaced the ACT sensor and voila', the smoking seems to be going away and the car runs and sounds amazing. Here is the video of a drive around the kart track: Drive and walkaround

Battery Box

I had some doubts about my 9lb battery starting the V8 when hot so I installed a 15lb battery. I took this opportunity to move the battery as far back as possible to improve weight balance. I built an aluminum box into a cover under the rear hatch, bolted the battery in and finished it off with a nice cover held down by Dzus fasteners.