In preperation of taking my 70 Skylark to the track I am thinking about trying these lower control arm relocation brackets http://www.umiperformance.com/catalog/index.php?main_page=product_info&cPath=2_32_38&products_id=29 Anyone here try this before? Is it worth the effort? Thanks
Why would you want to lower the rear mounting point of the lower control arm? Isn't it better to have it as parallel to the ground as possible? You could achieve the same thing (altering the instant center by moving it rearward) by installing a set of hop-stop bars and you wouldn't have to weld anything on your rearend housing. Just my opinion.
Looks like you are changing your pinion angle. That's a lot cheaper than adjustable uppers and lowers. I haven't heard anything about these, but changing your pinion angle does help traction.
Those lower brackets will not alter pinion angle at all. The upper arms hold the pinion angle firmly as long as you do not move the axle foreward or back. If you draw lines off the upper and lower rear arms going foreward, the two lines cross at some point. Raising the rear of the upper arm with no-hops will point the upper line downward at a steeper angle and cross the lower arm line more to the rear.. Lowering the lower arm at the rear will point its line at a steeper angle upward to cross the upper arm line more to the rear. Your shifting the I/C (instant center) more to the rear in both cases and creating a body lift leverage onto the axle as the body rises under the torque. This givea extra traction for a moment to get rolling faster with less wheel spin. With the lower arms dropped, the line crossing point is higher off the ground, and therefore hits a little harder than it will when using upper no-hops that point the upper arms down. Never install both systems together. Just choose which one you prefer. No-hops are hidden. Lower arms become quite visible when dropped and the sway drops with it. They each help in many cases for 11 second or slower cars.
Use upper adjustable control arms to adjust pinion angle (I like UMI). Leave the upper left arm set to hold the angle and adjust the right side a slight amount if the car pulls to left or right until it tracks straight off the line.
Finding the right shock and spring for the front and back, Adjustable upper and lower control arms are good! Just be carefull to not have any preload on the controll arms. In my oppinion, No hop bars and air bags are out of date big time!
Skylark springs made a tremendous difference on my GS. My original springs were way too stiff. I refused to try Moroso because I dont want my front end on the ground after one year, or my wheel alignment changing every month as the springs slowly collaps. Adjustable shocks will help also, especially in front.
I put a set of hop stops on mine and they didn't help one bit. Same 60ft, same everything. This is a mostly a street car and I didn't like they way the car rode with them on it so I removed them. They might work in certain sitations but they are not a cure-all for every traction problem. I just believe you should explore other options, like different springs, etc. before altering the geometry of your suspension.
Spohn has a new lower control arm that looks really cool. http://www.spohn.net/shop/1968-1972...-Adjustable-with-Del-Sphere-Pivot-Joints.html
ditto.... except IMHO the pinion angle. Changing any point or ride height has the potential to change your pinion angle. The rear lowering kits are designed with the points on an arc to hopefully not change the angle but you need to check. Also if you have a rear sway bar it will drop along with the lower control arms. My experience has been that anything you do is a shot in the dark unless you actually crawl under the car, measure all your points and plug them into an IC program. Everything is base on ride height. In my case what worked best was just to lower the car. I picked up .20 in the quarter (11.86 to 11.66) and launched a lot straighter just lowering the ride height 1". The ideal setup for me now would be to lower the upper control arm mounts on the frame 1" to get my anti squat to 100% and shorten the IC distance from the axle. I lucked out and ended up with the right pinion angle and didn't need adjustable uppers. If you look over the Moog spring chart there are about 5 springs in there that you can pick from with the right spring rate (for drag racing) that have different heights. http://101part.com/coilsprings/Moog_Coil_Springs.htm I ended up with a 5401. You can get them from Autozone or Advanced under the the Duralast name for about $60 a pair. I'm not sure if they're actual Moog springs or not but they have the same part number with a different prefix. See the attached pdf of the spreadsheet I use to plot my suspension points. You'll need a basic understanding of Instant Center and Antisquat but by plugging in different values you'll see what changes occur and can predict what direction a particular change will take you in. PM me if you want me to email you the spreadsheet.
I was told by a suspension expert to not relocate the LCA mounting points. Said it could break parts. The guy was a setup expert with a lot more experience than me. I do not see Dick Miller doing that either.
