I am speaking specifically to the 6-speed transmission car owners. This has been a topic of conversation here and elsewhere for years. We can start by acknowledging that there is a problem (unlike Dodge) Why does it exist? The Challenger torque was more than the suspension designers expected (or were told), but the design was done. The result was a rear suspension that could not handle the torque it was receiving, resulting in the rear wheels/tires "hopping". Hopping is a gentile word usually referred to what a bunny rabbit does...NOT... on our cars. It it a violent reaction to torque that the suspension just can't handle. It is not up and down (as the word "hop" would indicate) but an oscillating motion. Ok, what is an oscillating motion? Stand up with your arms at your side. Raise/bend your arms at the elbows out in front of you. Rotate your arms back and forth and up and down, like a steam locomotive's wheel drive links. That's what is happening with your wheels. I have test pictures showing; burn (3 feet), NO burn (in the air-hop 3 feet), burn 3 feet, NO burn (in the air-hop 3 feet) and so on throughout first gear, with the same results in second gear. The tires are literally grabbing at the roadway, releasing, and launching the rear wheels, off their suspension, jumping them in the air. "Torque Lunge" ( I think I'll call that description mine). What to do? First, this is a unibody car (no true separate chassis, but an integral body/chassis/body combo car). It twists. Thats right, your entire car twists under full torque. You want to stop that as much as possible. You want to keep your car as "flat" as possible under acceleration (balance). My first additions were the Mopar front tower brace, and the Razors Edge/Speedlogix four point, angled rear tower brace. The second (actually out of order for reasons to be explained later) was Whteline cradle bushings (advised by the Richard Petty Organization). The cradle is responsible for "holding" your actual rear (ham section) and thus the initial connection of your half shafts (axles at the at the ham) are also in motion (other than spinning). This should not move around, but it does. The bushings were designed for "ride", not extreme torque. When I say "move around" I mean up and down AND left to right. Not only do the bushings contribute to movement, but the entire cradle moves. It is only suspended by four bolts thru the bushings. So there's this whole shuffling thing going on The next step, components from "Hop Not". First is the "Hop Not" engine TORQUE rod. Remember torque and and keeping the "chassis" flat under engine torque (power). What this engine torque rod does, is limit the natural movement (torque) of your engine to the right within its stock engine mounts. What is gained...balance, restrain twist of the "chassis". Minor as it may seem, it was one of the most instantly recognizable mods I had done. It is very old school. Many 1/4 mile track car owners used a variety of methods to achieve this, some as basic as to link a chain to the left side of the engine block and the left "A frame".
Same results...keep torque balance.
The next step is a little more involved. It is the "Hop Not" 1&2 component, on top of Whiteline cradle bushings. "Hop Not" is basically a second set of shocks, designed and mounted at an an angle to counter oscillation,...remember?
It also pins and controls movement of the cradle bushings with heavy convex caps that are placed in areas of removed cradle bushing rubber that you remove (now concave). The reason I say a little more involved, is that the "Hop Not" was initially installed prior to the cradle bushings. The results were impressive, as long as you came out blazing, but not if you nailed it on a first gear on a roll out. Obviously a major improvement.
with the Whiteline cradle bushings installed, the "Hop Not" cradle bushing caps did not fit right. They had their convex
(bulge) to fit in to the previously removed ( now concave) stock cradle bushing rubber. Simple solution. Now that the Whiteline cradle bushings are installed, It merely required that the "Hop Not " bushing caps to be machined flat from their previously convex configuration. There is a second necessity. With the Whiteline cradle bushings in place and the "Hop Not" cradle bushings caps (machined flat) to go on top of this, the stock front cradle bushing bolts are now too short. You need to get two stock Mopar rear cradle mount bolts (they are longer than the fronts), and then you will have to shorten them???
Thats right, they are too long...for the front, even with the "Hop Not" caps. You will have to call it for yourself. Stick a thin screwdriver thru the cap and the bushing and the cradle mounting nut (which you can't see). when you have determined the correct length, cut the bolts and grind the ends to a semi point for "blind" connection to nuts that you can't see in the cradle. Now that that's done, add Whiteline front and rear sway bars, rear being positioned to the most vertical (of two positions), while on the ground. Add Speedlogix/Razors Edge rear billet tension arms, and kiss Challenger "wheel hop" By! By! And pay absolutely no attention to those who say; "it's those sh***y Goodyear RSA tires, or I lowered my car and "Hop" was gone, or I stuck my finger in my ear and "hop" was gone and anything else is crap, plane and simple CRAP. FIX IT, OR LIVE WITH IT. These modifications were done on my '09 6-speed 480 RWH ProCharged R/T at 20,000 miles. 56,000 miles later, tracking with Nitto 555's on SRT wheels...any time I want.