A couple of people asked about the rear alignment setup on my car. A picture of the LR is included below. (Forgive the rust on the rotor - I washed the car and then put it in the garage.) The idea was to be able to go between street and track settings without another visit to the alignment shop.

Dan at Vivid Racing set me up with the Agency Power upper control arms, and the TRG toe link.

To go between -2.5 degrees and -1.0 degrees camber takes 3 full turns on the upper front, 1 full turn on the upper rear, and 1/2 turn on the toe link to maintain factory toe spec. I'm very happy with the setup. Takes 5 minutes to change.

 

looks good! can you feel the difference in the rigidity of the rear end using the spherical rod ends? how would you compare it to the stock ones?

 

To be honest, I'm not sure. The big thing was being able to dial in more negative camber. That made the car handle a lot better.

 

Where are the dogbones set to when you make the full turns to get the -1.0 camber? In the 5mins to change do you have the wheels on?

 

I only do this when I am going switching street/track settings, so I am also swapping wheels and brake pads at the same time.

The dogbones are set to wherever the alignment shop put them when they did the base street alignment. The wheels are off for the change. The dogbones are relatively hard to reach with the wheels on, even from underneath on a lift. You can turn them ok, but can't readily loosen or tighten the jam nuts.

When I have an alignment done in the shop, it saves a lot of time for them to first remove the rear wheels, loosen the jam nuts, then replace the wheels and do the alignment turning the dogbones by hand. Afterward, they take off the wheels and tighten the jam nuts. It took me a few tries to convince them to do it this way, but it is really a lot faster.

Jon

 

the upper control arms are the same length in stock form so why is one arm adjusted longer/shorter? I feel by doing so you will affect the caster of the rear wheel. Something like the kinomatic (not sure if spelled right) toe on a 993.

 

The geometry and attachment points are different, so the relative change produced by different turns on the different control arms should be expected. We are talking about a difference of 1 turn on about 24 threads/in, which is about 1 mm. The objective is to produce the desired camber and toe. I arrived at those numbers by having the alignment shop set the car up both ways (street/track) and recording the differences. I check the alignment after I set it using Smart Camber and Longacre toe plates.

Caster is not much of an issue on the rear tires, since they don't steer.

Jon

 

The toe in the rears helps to steer the car. also your trial breaking will change. Ask anyone who had gone through this trying to setup there 993's. Also why would they sell a tool for this job if it was not needed? Have the shop set your rear for street and put the front wheel reflectors on the rear and see where your caster lay, then do the race setup and tell me if I am wrong. How can the hub travel the same ark with the upper arms at different lengths?