Suspension Griggs rear set up on my 1991 GT, need help with set-up

drummerkid14

Member
Nov 30, 2011
15
2
13
I bought this car about 2 weeks ago. In addition to the Wilwood brakes all around, the suspension has been upgraded as well. I had planned on going with Maximum, until I saw the car and realized it is already pretty well set up. The rear is adjustable lower control arms with heim joints on the front mounts, panhard bar and torque arm. A few things I am looking to adjust, and I am looking for some guidance. The main problem is that the rear suspension feels like it is binding while turning. There is a lot of NVH, and I think the first problem could be the spring rate in the rear. Another issue could be the heim joints. From reading on the Maximum website, they recommend rubber bushings in the control arms when running a TA/PHB set up. Not sure if I am understanding that correctly.


#1, the rear springs are Eibach sportlines, and I think they are way too soft for the set up. The front end is set up on coil overs, but I cannot find a spring rate or marking on them. So my plan is to order the Maximum Motorsport torque arm rear springs with the 375-440 lb/in rating and the urethane isolators. Currently there are no isolators on the springs. I think this combo could be causing the suspension to compress more than designed and causing the binding/NVH. The shocks are Koni, not sure of the model #.

#2, the heim joints are super noisy, and I lubricate them? Or should I just look into selling these and getting the adjustable Maximum arms. I will have the car back up on a lift next week, and I plan on inspecting the torque boxes, and I can clean/lubricate the joints at the same time.

#3, the Griggs torque arm mounts differently to the cross member than the Maximum. The Griggs mounts on a vertical bolt/bushing set up, and the Maximum mounts on a horizontal that slides into the arm. Because of this, the previous owner had to cut out the H pipe crossover tube, so the car has 2 massive holes in the pipes. Debating between just patching the holes with new metal, or patching and adding a new crossover tube in a different spot.

A last option is to remove all the Griggs components, try to sell them for a few hundred locally, then spend $1300 on the Maximum set up of springs/isolators/adjustable LCAs, PHB and TA. Then I can start “fresh” with a set up that actually has tech support. The Griggs website is pretty terrible.

Here is my car on a lift. (the PHB is level to the ground when the car is sitting on the ground)

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Here is the Griggs TA with the different front mount

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And here are the adjustable LCA's, this is a photo I found on the internet, my LCA's have the adjustable spring perch.

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drummerkid14

Member
Nov 30, 2011
15
2
13
So after talking with Griggs, this set up is about 20 years old. He kinda laughed when I told him about it. Sounds likes everything that pivots (bushings, joints etc) needs replaced.