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Quad Eccentrics - Adjustable Rear Control Arm Bushes

5K views 34 replies 7 participants last post by  blackgoat90 
#1 · (Edited)
Just picked up a set of SPF0877K Super Pro Eccentrics. The info here is somewhat limited(yes I did search). I'm hoping to compile all the info about then in this thread for future, easier use.

My car is an 04A4 with a Hinson 1piece driveshaft, lowered on Mavman coilovers and single adjustable springs. Every single bushing is Whiteline except these Super Pro eccentrics. I have a cradle alignment tool so my cradle came out for this process.

What quad eccentrics allow you to do is adjust toe and camber while losing the factory toerods. It is said the toerods will cause binding and could damage the diff if not removed. The inner bushings adjust toe while the outers camber. It's helpful to your tires to achieve 0° camber both for longevity and increasing your contact patch. Having a little negative camber helps in cornering, but I'm going for a drag/weekender setup.

So the rumor is the Whiteline single-bolt design is the best with the least chance of backing out, but they're discontinued. Apparently there was an issue with the Pedders eccentrics where the nut would back off and you could lose your bush and even the ear of the subframe that the control arm mounts to.

Duckman told me these Super Pros are the best on the market right now. Nordlock washers should be used instead of the split washers provided.

I saw another post Here that the Pedders bushings need to have the thicker inner lip of the bushing facing inwards. The Super Pros appear to be all the same thickness.

Here are the instructions that came with my set of Super Pro bushings:

View attachment IMG_20190919_140856638.jpg

Admittedly, I'm just a guy in his garage so I could be misinformed so feel free to chime in.
 
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#4 ·
The toe control rods would only cause binding if you put a stiff bushing on the inner mount of the control arm.

Also, it is a function of suspension design that the camber and toe will change throughout the range of motion of the control arm.

Setting zero camber at ride height only gives you zero camber at ride height. You will have negative camber when the rear suspension is loaded.

Having poly bushings helps with toe changes that happen while the rear suspension is articulating, as the control arm won't squirm around under load, but imho just having a stiffer toe control rod is a good option.

You may consider using a poly outer bushing and letting the inner bushing flex like it is supposed to. It will take more stress, but at least the suspension will work as intended.

If you wish to have more control, you need to tune damper and spring rates as well. As was said, more travel = more camber change. You can limit this to an extent.
 
#7 ·
Red loctite works ok on smaller diameter bolts. Not sure of the size of the control arm mounting bolts, but you might be ok and not need heat to get them loose if you have to.

Lock washers or nylon locking washers are not that great, from what i understand.

You can try nordlocks or a similar type of locking system, or see if you can find prevailing torque nuts of the size and grade you need.
 
#9 · (Edited)
Sorry, i had to edit this after i took another look at it. Also, odd how they have the spring washer in between the bolt and nut in the pictures on superpro's site, if you ever check, btw.

Now that i look at the instruction pdf for the superpros and how these work and are adjusted, i would just use it as is.

No loctite, no different thread locking mechanism other than what is provided. I think trying to use anything extra would just interfere.

I think the sides of the eccentric collar have ridges that help grip the mount ears and keep the collar from rotating, as well as having spring washers on both sides.

I would just follow the instructions faithfully.

At most, perhaps replacing the spring lock washers with another type of washer, such as a nordlock set like i mentioned.
 
#10 ·
Ah ok - sorry. I just have the outer adjustable whitelines. Maybe not the quad kit. If you really want good traction on a launch - you can do the cradle box mod, put solid subframe bushings, and put eccentrics in the outer arm just to do tiny camber adjustment. Gforce recommends not even using eccentrics with the box mod. Just a thought if you want to go that far.
 
#12 ·
I am lowered on Mavman coilovers with single adjustable shocks. It was my understanding that we want 0° camber at the rear to achieve maximum contact patch and minimum camber change on launch. I'm talking just about drag racing, but info on other race types would be great too.
I really don't want to cut up my control arms since I just spent a ton of time and money revamping the whole rearend. Maybe I'll buy another set in the future and do it.
The bolts that came with the Super Pro kit are surprisingly small for how much load they get. That's why I suggested loctite and washers.
I also have new Whiteline poly non-adjustable bushings, but thought I'd have too much negative camber throwing those in?
Honestly, quad eccentrics seem like a hassle, but I don't wanna shred the inner parts of my tires only and cause other issues.
 
#13 ·
ok, so you are lowered. i had the impression initially you wanted to do them for other reasons, not sure why. these cars aren't conducive to being lowered. it just sucks dealing with it.

even stock cars have inner tire wear issues with the rears, because of the dynamic camber and the soft suspension. granted, it's worse with a lowered vehicle, so yes, you absolutely want 0 degrees of camber with the suspension sitting at rest. as far as drag racing, you do also want to start out with minimal initial camber with the suspension at rest, but you also want to minimize camber change during acceleration, which is going to happen as soon as the rear end squats. but since you have coilovers in the rear, you should be able to have some adjustability to control squat, which will also minimize dramatic camber changes.

that being said, the long bolt needs to bottom out in the eccentric collar and still leave enough exposed thread to allow the "jamb" nut (i guess i should use that term loosely) and the spring washer to be free so you can make the adjustment, then allow you to tighten it. Add a washer, and you may not be able to do that anymore. Also, it will reduce the number of threads available to grip on either side.

using a nord-lock washer of a similar thickness, but larger diameter might work. it should also lock much better than the spring washer. i don't think using a lock nut would be a good idea here. nylock nuts kinda suck, and a prevailing torque nut could work, but by design they are very hard to turn on the threads and you'd risk turning the long bolt and ruin the adjustment as you tighten it. it would also throw off the actual tension being used to hold the assembly together since more torque is being used to overcome thread friction, so that throws the factory torque spec out the window.

using loctite may not be what you want to do. it's good practice to really plan to take stuff apart some day, even if you don't initially intend to. if the bolts are small enough and torque values low, you probably won't need to heat it to free up the loctite, but at the same time, you will still gunk up those threads. it will make it a bit of a pain to reassemble and achieve the proper torque values the second time around unless you take the time to clean everything and chase the threads.
 
#15 ·
I sent this email to Super Pro to try and get them to weigh in:

Bought SPF0877K Super Pro kit for my 2004 Pontiac GTO and the instructions note that one bush is 27mm and the other is 30mm but not where to put which in the control arm. I'd also like to get some advice about using Nordlock style washers over the supplied split washers as that's viewed as a superior fastener. What is the required torque on the bolts and the locknut? What can I do to prevent them from backing out? Can I just use the camber adjustable outer with a poly OEM inner and a beefier toerods?
 
#17 ·
#16 ·
A stiffer spring and stiffer damper settings should help minimize squat. I would start with the damper settings first. From what i've read here on these forums, guys tend to have the most luck with their shocks on full stiff at the dragstrip.
 
#18 · (Edited)
Thank you Duckman for chiming in as to which goes where.

Sent this email to Geforce:
"I apologise in advance for the long-winded email.
So I have a 2004 GTO lowered on Mavman coilovers with single adjustable shocks. Not sure how much lower I am than factory, but nothing ribs so far. I have the stock 17's with 245 profile tires making stock power, for now. My question is about the rear control arm alignment. I have a set of Whiteline poly subframe mounts and an alignment tool, but the control arms are giving me trouble as I can't really get a straight answer. I have a set of Whiteline OE style bushings I can toss in, but from my understanding they may create excessive negative camber. I also have a set of Super Pro quad adjustable eccentric bushings which calls to delete the stock toerods. I'm not confident with any shops around here to accurately align the camber and toe with those. Plus, I've read horror stories about the bolts backing out. I could use the camber adjustable outer eccentric, stock style Whiteline poly inner, and your beefier toerods though. I'm trying to get 0° camber and minimal camber change on launch. I just want to go in a straight line fast. Cutting up the subframe and control arms are out of the question for now. I'm mainly reaching out to get some feedback or advice since I've never had this much adjustability and options for the rear of a car before."

And got this response:
"
Hello sir, thanks for reaching out! Our GTO guy said he really only has experience with going the cradle box route - so with what you're looking to do he would really just be guessing at what was best. Perhaps you could find someone on the forums who has done a similar setup to what you are wanting to do? Although I'm sure you've already looked. Apologies I couldn't be of more help sir, please let me know if there is anything else I can help you with and have a great day!"

I don't mind running the poly Whiteline non-adjustable bushings I have in addition to their toerods and subframe boxmod.
My end goal is to have 0° camber at rest and as little change as possible on launch. The coils and shocks shouldn't be an issue.
 
#21 ·
If you're OK at welding, and get the pre-welded boxes it should be a breeze. I would recommend putting the box in place with the stock bolt in the stock hole. Then tack the new box to the subframe (aftee you have cut the top out of the old piece of course), and then drill the hole with the new hole as a guide. If you dont tack it to the frame first, the box will move around as your drill your new hole.
 
#27 ·
I've looked at their site and I see the pics, but I'm a very detail oriented person so I had them send me actual instructions. I saw what you're saying about the new hole now. Does the boxmod completely fix the camber issue though along with coilovers and poly bushings? I'd like to rely on these quad eccentrics as a last resort. Now I'm leaning toward getting Geforce toerods, solid cradle bushings, and the box mod.

Something that concerns me is their shop goat having positive camber on the product pictures for the boxmod.
 
#30 ·
Via Andy Kollar - you can do eccentric bushings in outer control arm spot and keep your toe rods. If you do eccentric bushings on the inner control arm mount, you must delete your toe rods. So - to keep the toe rods, ya gotta put a regular poly bushing (non-adjustable) in the inner control arm spot.
 
#35 ·
Once you go quad eccentrics you have to make sure to take your car to a non-bonehead alignment shop anytime you need to get your alignment checked. They have to know what they are doing when it comes to adjusting it, and make sure they tighten them enough.
 
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