Just editing this first post to clarify things a bit. The tubular control arm I used was made by RCC(no longer in business). The only change I made to it was to weld the bracket on that holds the new control rod to the arm. My latest improvement eliminated the need for a connector on the control arm. The control rod now goes directly to the frame, eliminating any movement caused by flexing of bushing material. So the lower control arm you use to make this set up does not matter-stock, tubular WCF or anything other than the Held/Arraut bumpsteer kit.The lower control arm is just along for the ride when you mount the control rod to the frame. The part that I made bolts to the spindle and is not an RCC part. This is a part that anyone with some fabrication skills , a mig welder, metal chop saw, a vice, small drill press and a hand held grinder with a cutoff wheel can make. I do not have drawings for it. This bumpsteer bracket can be used with the stock strut assembly. I went the full monty and made my rear suspension in to a SLA setup but that has nothing to do with bumpsteer. For 84 to 87 Fiero's only. This was not an original idea on my part .While I was trying to figure out how to make an upper control arm for the rear of my car , I saw Yarmouth Fiero's design for a bracket to hold the spindle in position without the need for the tie rod that GM so thoughtfuly put in the wrong place .Anyway , I came up with a version of YF's bracket and it seems to work .Not tested in the real world yet , but all indications are that it does the job .Using this bracket allowed me to use an upper ball joint and more traditional "A" style upper arm for my build .I think this design could be adapted to a stock lower arm too .The lower arm you see in the pic is an RCC arm , no longer available .Just throwing it out there , more pics can be seen on my build thread in the construction zone .
[This message has been edited by wftb (edited 12-13-2017).]
I think it would work on a stock arm .I do not have a stock arm or I would see if it is possible .This is an RCC arm , the other MFR arms are a bit different .The WCF arm I just looked at does not have a sway bar mount .
Originally posted by wftb: I think this design could be adapted to a stock lower arm too .
I doubt the stock stamped steel lower rear control arm would be stiff enough to resist the loads and would result in control arm flexing, unintended steering, and potentially the risk of fatigue failure, in my opinion.
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Originally posted by wftb: Using this bracket allowed me to use an upper ball joint and more traditional "A" style upper arm for my build.
Have you decided how you intend to attach a shock and spring to your new configuration?
That is what I am working on now .But even with my propane heater on , it is hard to stay in the garage for very long .Bit of a cold snap going on around here now .
Those are the arms that I have had on my car for about 3 years now .I just did not like how heavy they are and with my Ecotec/F23 setup , there was interference issues .The bracket I have made weighs less than half of what that square bar assembly that forms the spindle mount weighs . The bumpsteer arms from Arrault work fine on most cars , they just fell short of what I am looking for .Here is where my coilover assembly is approximately going to be mounted .The spindle is almost at full droop .I need to do a lot of grinding and make up the bracket that will be welded on to the spindle adaptor but it looks workable. .The shock is sitting 17 degrees from vertical and that will be increased to get the suspension arm travel to shock travel ratio I am after .
Just keeping this thread going for people that do not visit the construction zone .I now have the car supporting itself on its new suspension .Still a lot of things to do to make it roadworthy again but everything looks very promising . This pic shows the brackets that hold the upper coilover mounts in place .I had hoped to make these adjustable , but there is not enough room on the passenger side to do that .I added compression bumpstops to the coilovers as there is not a huge amount of travel .I think it will be adequate , but these bits of rubber are cheap insurance against breaking expensive shocks .
An off topic question if I may. Did you see any evidence of the F23 having a differential center line of about 10 mm toward the passenger side when you put your axles and everything together on your rear spindle assemblies together? Or maybe you saw this ahead of the game and compensated for it?
Sounds kinda crazy, but my psychiatrist couldn't answer my question!
Like your shrink , I really cant tell you .When I first put it in the car I just hung it over the cradle and measured to make sure it would not hit anything and bent up some steel for mounts and carried on .More info is in my build thread , ecotec swap , construction zone . Thanks for the reply , have a great day .
In order to be able to align the new suspension , I made some eccentric washers and welded on some retainers to the upper arm supports .If you look closely , you will see some slots in the washers so they can be turned with a straight blade screwdriver .There is also a reference line that is scribed into the arm mounts so that the arms can be set at the same angle to the frame as the lower arms . The upper arms are adjustable to set the camber and by using shims between the arms and the eccentrics I can adjust for slope of arms relative to the ground and amount of anti squat can be adjusted as well .Toe in/out is adjusted by the link on the lower arm .
[This message has been edited by wftb (edited 10-28-2015).]
My new rear suspension is completed and I have done some preliminary testing that shows that it works .There is going to be lots of fine tuning for sure , but that is why I made it fully adjustable .I took it for for a ride around our backyard today (1.2 acres) and I am very pleased with the results.I thought I would post some more pics on this thread just to show that I have accomplished what I set out to do : build the first SLA rear suspended stock wheelbase fiero . More pics and info are on my thread in the construction zone
My concern is that your toe links will have enough leverage against the add-on brackets to work them loose. That's what stopped me from making such a bracket myself. I just didn't have enough confidence in the design. Hopefully, I'm just being paranoid.
Thanks for the reply . The brackets cannot come loose , they can only bend under extreme forces .The way i built them , the brackets box the wing on the spindle - they cannot flex or move except where they attatch to the rod end .And that would only be the kind of force you would encounter during an accident - the length of the unsupported part of the arm is very short and extremely stiff .
[This message has been edited by wftb (edited 02-24-2016).]
I am now driving the car on the road again and everything is working well . I am very pleased with traction and stability so far .I really think a bumpster bracket like this could be made to work with a stock 84 - 87 control arm .A reinforcing plate welded on the bottom of the control arm where the inside of the arm mounts would make it strong enough . A stock stamped steel control arm is a lot stronger than most people realize .Especially the rear control arms of an 84 -87 fiero , because they were originally designed for the front end of the old front wheel drive X cars .
If the rear tie-rod is just 2 heim joints connected by a turnbuckle... Couldn't you attach a flange to the turnbuckle that could connect to a rod assembly that was hinged so it was 2 rods connected in an L shape where the top of the L was attached to your strut tower. The length/ratio of the two legs is there to basically limit the amount that the turnbuckle would be twisted on the fly as your suspension travelled up and down. Hence you'd have the toe self-adjusting to your suspension travel and essentially have a slight "all-wheel steering" effect...
I think I would need a diagram to get what you mean .With the suspension I have built , I get pretty good camber gain with the upper A arm and eliminating the strut and going with the coilover .But using a lower control arm like I have built with a stock 84-87 strut style suspension would eliminate the bumpsteer problem without adding the extra weight of the Arrault arms .I am not a big fan of rear steer suspensions .That would be way beyond my design capabilities . Heck , what I have built is probably stretching my capabilities but it is working well so far.
[This message has been edited by wftb (edited 03-17-2016).]
Very nice, WFTB. I've had something similar on the drawing board for some time. You inspire me to finally do it. One question. Are your inboard control points parallel to the chassis center line? In the stock pre-88 chassis they where not.
Thanks for the reply .What I did with the inboard pivots of the upper control arms was to make them follow the same line as the lower control arms .It would have been easier to make them paralell to the centre of the chassis , but I had no way to tell what effect that would have on the geometry .So I just copied the angle of the lower arms .I have put about 100 KM on the car so far and I am happy with it . I have not driven the car in a week because of the snow we are still getting up here . I need an allignment to see just how good it is . I am pretty sure all four wheels are pointed in slightly different directions as far as toe goes . I have thought of a way to make a better ball joint adapter . I have some useless spindles (sloppy ball joint holes ) that I can hack the top hole of the strut mount off .Then I could make another ball joint adapter that would give me a much lower king pin inclination angle . And the inner pivots of the upper control arm could be moved outboard about an inch , giving more room for the shift mechanism and the charge piping .Doing this should result in a more stable instant roll centre . I have not noticed any instability with the setup as it is now , but where a problem like this would show up would be on a banked cloverleaf that is on the bumpy side . So that will be next winter's project if it is needed .
[This message has been edited by wftb (edited 04-07-2016).]
Going to make a slight change to the design .The clevis is going to be replaced by another heim joint and is going to be mounted to the cradle .On large bumps I am getting flexing of the rear inner arm poly mount .
I have now added the new control rods from the bracket to the frame .You can see that I had to hack up the cradle to get the inner heim joint in the right spot .Over next winter I will smooth that out and weld in a vertical brace .For now it is fine , that area is really thick and strong as it is .The best thing I like about this design is it takes the lower control arm out of the equation .Build the bracket for your spindle , add the control rod and you are done .It does not matter what kind of lower control arm you use(except of course the arraut bumpsteer arm) .I did have to use longer bolts to hold the new assembly together .They are available on Ebay .The ones on now are M12 by 90 flange chassis bolts and nuts .I would like slightly longer bolts , these just barely poke out of the nuts right now .I have some on the way ,I will put them in when they get here .
Another mod that I have done is I made new upper mounts and now the coilovers sit close to vertical .This made a big improvement in the ease of motion of the suspension .The angle that the shocks were initially on combined with the design of my strut stub adapter caused binding , restricting the amount of travel . To get the same ride height with the new coilover angle , I was able to back off the preload over an inch . Now I can run stiffer shock settings without the gokart no movement feel .Pics are in my thread in the construction zone .Over the winter , I am thinking of mounting the coilovers on the upper control arm .That should improve the motion and get a longer wheel travel .
The car is now in the garage for the winter .Plans for this year are a better upper control arm mount/adjustment system and a lot of general clean up and paint .Am I still alone as the only one that has done this ? Would be nice to see what other people have done along the same lines....
I have had the car on a road course to see how the system works under extreme conditions and the results were very good. Nothing bent or worked itself loose, the car handled well so the next step is going to be a better upper arm mount. The stack of washers I have now did not cause any problems but I have a rough idea of a more permanent and adjustable solution.
Thanks for the reply. Very true that there no longer seems like there is much interest in this type of modification. Maybe the fiero has reached an age where people are more interested in restoration and preservation than mods. I am just happy that I can post my stuff on a site like Pennock's.
So if you wanted to improve on the RCC set-up, what would be on the list? I'm going to making some for myself. If there's any interest, I might make a few extra.
I am not that knowledgeable about suspension geometry to really answer. The RCC arms are really just stock arms made out of tubes, all the geometry is stock. The advantage is that they are lighter than stock and look better. The bumpsteer bracket works well with them, and I noticed an improvement when I bolted the tie rod directly to the frame. I wish I had thought of that when I first put it on the car, but I was basing my design on Yarmouth Fiero's. In hindsight, I think he has made a mistake. He does not come onto Pennocks anymore so I doubt if he has even seen what I have done with his idea.
I was meaning more along the lines of "the pinch bolt is too long and works loose" or "if the toe link attachment point on the fabbed bracket was moved closer in toward the spindle, there'd be more room for a 14" rim" or "this one's a little heavy" or "?"
Not to denigrate someone else's work but the original spindle bracket looks a little rough. I'll weigh the stock control arm just for the fun of it.
[This message has been edited by mender (edited 11-14-2017).]
Thats because I made the spindle bracket, not RCC. I have never been one to grind off the rough edges, clean up rough welds and paint my work. I am lazy that way, always in a hurry. So my stuff always looks a little rough around the edges. What would I do to improve it? Probably paint it sometime.
When it comes to moving where the spindle bracket has the outer tie rod end I do not know if it could be moved inboard or not. I do have a bit of chassis design knowledge but it is all from Herb Adams book. So from researching the book I decided that the outer tie rod end had to be below the OEM tie rod end mount on a line joining to a line straight out from the ball joint ball centre.(the angle of the lower line that comes straight out from the ball joint was determined by the direction of the pinch bolt).So locating the rod end any where else may not put it properly lined up. Now a proper pinch bolt is hard to find. the OEM pinch bolt had a longer than normal unthreaded portion of the bolt. This was made like this so no threads(or very few) would be touching the groove in the ball joint stud. New ball joints usually come with a normal longer thread bolt. Makes for a sloppier ball joint stud and tightening it enough to get rid of the sloppieness usually bends the bolt. As far as making the bracket look nicer, use of larger continuous pieces down the sides would help the looks and maybe lower the weight a bit. But the bracket as is- its not very heavy. I think it looks bigger in the pics than it is, it really is a fairly compact piece. I have not weighed it though.
