Since you can't really see by the photo , this is what I have done so far : I had to cut down the frame rail because I did not like the slope the upper arms will be at .After cutting , I welded a 1"by1" X 1/8" wall square tube down in to the exposed channel .Then I welded a 2" by 24" 1/8" steel plate along the outer face of the frame rail .This was welded to the square tube as well .Another long plate was welded to the inside of the frame rail .I replicated the shape of the inside of the frame rail by first welding it in the middle and then pulling it in to the rail where it bends with C clamps .I will be welding a 1/4"thick top plate on and a version of the arm bushing mounting frame that you see in the picture will be bolted to the plate with 1/2" grade 8 bolts .The bushing assembly will be adjustable with eccentric washers and mounts where two of the bolts are .This will be the toe adjustment , camber will be adjusted by the cam bolts on the inner arm mounts , identical to the way the struts are adjusted .I was hoping to get more of this done today , but I do not have the 1/4 plate yet .
[This message has been edited by wftb (edited 12-25-2014).]
Now I have the inner bushing mounts welded in place .I can now bolt them in place on their perches and start making the upper arms .I still have a lot of boxing and filling in to do , but that will wait till I drop the cradle .There is just not enough room to do a decent job of it with everything in place .
So the car is now in the " work on " position in the garage .This spot was occupied by our 1991 Civic wagon while I built a new stainless steel exhaust , put in a new gas tank and rebuilt the front and rear suspensions .The plan for this winter is : 1- make and install an upper control arm /coilover suspension system 2-Utilize a stock rear knuckle and rear brakes as part of this package . The reason for this is twofold : I want the lightest suspension possible and I want a parking brake . The stock disc is very light compared to the 11" lebarron rotors on the back now .The stock rear caliper is a fairly lightweight AL unit .On my fiero , judging by the amount of wear on the rear pads vs the front pads , the rear brakes do not provide any more than maybe 30% of the total braking .And my brakes work really well on the street and on a track .I use the stock MC and booster and proportioning valve .I will probably gain some unwanted rear brake fade but I am not concerned about it . And in the looks department , stock brakes have no cool factor at all .But I am hoping the gains outweigh the losses .No pics for now , my old camera crapped out and still waiting for the new one to come in the mail .
As it appears from your comments and photo's, is it safe to assume that you're building an SLA (short/long arm) rear suspension? If so, are you doing this to gain more negative camber under jounce/compression?
You also mentioned you want the lightest suspension possible. Is it fair to say the extra steel plate added and the upper control arm would make this set up slightly more heavy than stock?
[This message has been edited by Lunatic (edited 12-30-2014).]
In the old days we used to call them double wishbones .But yes a SLA is what I am working toward .As far as weight goes , the frame bracing will add about 4 pounds a side .Getting rid of the Held bumpsteer kit and going back to the RCC lower controls arms I used to have on the car will save about 8 lbs per side .The bumpsteer kit works well but it is heavy .I don't know how much going back to the stock disc and brakes on the rear will save but it will be slightly lighter than the 11" disc I have now .And a coilover compared to a strut is always lighter .I will gain the ability to add more negative camber if I want , but I do not know if overall that is an advantage over a strut system .From what I have observed and learned over the years , the more a strut compresses as it leans in to a corner , it gains negative camber .There has to be a reason Porsche uses struts on all 4 corners of the 911 . I do not think an SLA does this , at least not from my experiments on the front of my fiero . What I hope to gain is adjustability and a much better shock / spring unit .Having a more modern style coilover instead of the old strut in there means I can use all the latest technology if I want to .
Ah yes, I now recall the Held kit that was on the back of your car. It did look a little heavy and bulky. I like where you're going with the rear suspension. I once read an article, redesign a Fiero suspension for better geometry here on PFF. It's a good read if you have a spare hour or two! I'm looking forward to the modifications and if I can assist you with any laser cut components, let me know. PS-I have a spare set of coil-overs should you want/need them. I think they're only 8" springs but they might work for your application.
[This message has been edited by Lunatic (edited 12-31-2014).]
Thanks .I have read pretty well all the suspension related threads over the years and while it probably would be nice too improve on the geometry , there really is not enough room to make much in the way of changes to improve things much .And my car does not suffer from most of the bad things that happen to stock 84-87 fieros .My car does not "squat" under acceleration nor does it dive under braking .I figure the reason for this is that it has been lowered substantially and the engine weight is lower than stock .With much wider tires in the back I can get out of throttle induced oversteer by lifting off the throttle without having to worry about a spin out .So what I hope to do is just replicate the up and down motion I have now but do it with an upper control arm instead of a strut . After my first mock up , I will measure what changes happen as the suspension goes up and down .Then make changes as needed , and then finalize the design .And then I will definitely look to get some pieces laser cut , thanks for the offer .
I have now mocked up a set of arms .The inner mount is tack welded in place .What I have to do now is put my old RCC arm on with a stock spindle and see how it moves .With the bump steer arm on and the strut disconnected at the top , the arm seems to move up and down pretty well .But I will not know if I need to make changes until I have it bolted to the RCC arm and take proper measurements as I move it up and down .Then I can use the mock up arm to make a fixture to make two identical finished arms .
I needed to check straightness of the arms so I lightly filed down a piece of 1/2 all thread rod lengthwise so it would fit snugly in the 12 mm holes in the bushings . Slid the big end on and this showed I am not quite there yet .The outer ends do not line up straight so I need to fix that before I carry on .
I gave up on the idea of an 88 cradle swap mostly because of having to go stateside to get one .But in the end I really wanted to get rid of the struts .I like the coilovers I have in the front and that is what will going in the back .I considered rod ends for the easy toe adjustability but the delrins I am using are grease able and should hold up better for street use .That sure is a nice collection , thanks for the offer .
One thing I should mention is the finished design will feature a cross brace between the arms so that they become a single arm per side .That will be the last feature I add , because it is really easy to take them in and out the way they are now .I want them to be really stiff , to eliminate unwanted deflections under load .
I checked all the movements with the upper arms and the bump steer arms .With the chassis sitting level , I jacked the suspension up and down through its range of motion and it looked good .Camber remained mostly constant with slight changes at the extremes of travel .Very little toe change and again only happening at very bottom or top .I tilted the car and simulated a big corner lean and the tire patch ended up at 0 degrees so i was happy with these results .So I replaced the bumpsteer arm with the RCC arm and stock spindle .Camber at ride height became -5 degees and not enough adjustment on the strut to get it to -1 or even close to that .The RCC arms seem to push the bottom of the spindle out .Now I am going to move the mounts for the upper arms further outboard to get the adjustment back .And the toe will probably be out of wack now too .
[This message has been edited by wftb (edited 01-16-2015).]
I figured out how to cut the mount portion off of my old coilover strut .I thought it could make a good base for my upper arm /coilover mount .I managed to save the coilover kit pieces so in 2 months or so I can sell them in the mall .Once I am done using this piece for mock ups and measuring , it will be hopefully transformed in to an all purpose mount .
[This message has been edited by wftb (edited 01-18-2015).]
That's the nice thing about winter in Canada, it gives us time to work on our rides in preparation for the next driving season. Keep the R&D coming! I'm interested in the coil over sleeves and springs. Let me know once you're ready to part with them.
PS-I have a short set of coil overs should you be able to utilize them.
I will save the kits for you . I have my old carrera coilovers that used to be on the front of the car and I hope to use them to mock up a mount system .They are a popular size so if I can make them work , then my options for coilovers will be huge .Right now I am trying to decide whether to make the arms longer or to move the mount points out .
So this is what I did today .I cut off some metal of the former strut bottom so that i could mount the plates that you see .After the bolts were mounted as shown , I welded the flange nuts to the plates .Then I cut a piece of 1 1/2" pipe that will be welded in between the plates as a spreader .Another pipe stub mount will get welded on both sides to hold the arms to the spindle .
[This message has been edited by wftb (edited 01-21-2015).]
So I have made some more progress .The mount that goes on to the spindle stub to hold the arms is now completed .I have run in to a snag though .The camber adjustment on the lower strut cam bolt no longer does anything .This was supposed to be where small changes to camber would be made .But nothing happens when the cam bolt is turned .Looking at it , I think the solution is to flip the mount and have the cam bolt at the top .A good thing I did not weld the mount I fabbed up to the old part of the strut that it fits too .here is the mount before welding : Going to see if I can correct it tomorrow .I do not want to have to unbolt the control arm mounts to make small changes .
Looks like it will not be possible to flip the mount to make the cam bolt work to change camber . Right now , rotating the cam bolt just gives a small adjustment to upper arm angle .I put the RCC arm back on .I had a bit of work to get the ball joint stud to fit tight in to the spindle . The gap was full of crud and rust so it would not pinch tight on the stud .Also the bolt was worn , allowing some unwanted up and down slop .I cleaned out the crap with my grinder and a thin cut off wheel and used the good bolt out of my bumpsteer arm and now it fits factory tight .The upper arm mounts were tightened down at a "best guess" position with regards to camber .Toe position right now was determined by the bumpsteer arm setting and should be close to factory setting . So I bolted it all together and took some measurements .At ride height I got lucky as my guesstimate gave me 1 degree negative camber , a good starting position .Going up and 1 1/2" both ways from ride height results in no camber change .A slight positive camber change occurs in the upper areas of compression travel and it goes more negative at full droop .Nothing to worry about there as suspension will almost never be in those positions on the road .The thing I am very happy about is that throughout the normal range of motion I could not measure any toe change .From full droop to upper limit of travel is less than 1/32" of toe in .Again , nothing that will happen during normal driving .The one area that I feel the need to improve on is resistance to flex .It could just be that I do not have the new mounts welded to the strut supports yet and the lower arm is not bolted tight to the cradle yet , but reefing on the backwards mounted disc does give a very small amount of movement .To make sure I can eliminate the unwanted movement , I think I can add some angle brackets from the outer side of the arms to the most inboard part of the strut mount .This should get rid of what little movement there is , and improve the mount to double shear . The arms at ride height are level and paralell to each other .There is no binding going up and down , very smooth .Now I need to get the proper tubing I need to make the finished arms and build the extra braces .I think I have a basic design that should work .
[This message has been edited by wftb (edited 01-24-2015).]
Now that I got some daylight on the subject , I can clearly see that the movement is caused by not having the lower arm mounting bolts tightened .Going to make the braces any way , but they are not really needed .
Looks like i can only make a brace for one side .If I put one on both sides , I won't be able to get the mount bolts in .One brace is adequate from what I can see any way . I think there is a little confusion about how this is supposed to work .So to go from the bottom to the top , this is the setup: RCC lower control arm with stock ball joint Stock spindle No toe link arm Custom built upper arm mount welded to the cut off bottom of the original strut assembly and bolted to the stock spindle with stock mounting bolts Custom built upper control arms with delrin inner and outer bushings. QA1 coilovers pivot mounted top and bottom.I have not quite figured out how I am going to mount the coilovers yet , but I have a rough idea that will work I hope .As you can see by the picture , I have more welding and some clean up grinding to do .I just ran out of propane so that is why I am posting instead of working .My garage is not insulated so I use a propane heater to stop from freezing out there .The garage is well ventilated , so the fumes are not a problem .The picture shows the bumpsteer arm attached to the arm mount .I just use it as a "holder" while I weld .
[This message has been edited by wftb (edited 01-25-2015).]
All welded up .Needs more smoothing with the grinder before I paint this assembly .I found a place in Mississauga where I can get the right tubing to build the arms with , might go down there tomorrow .
The pivot mount will be outboard of the pipe that is welded in the middle and between there and the the spindle stub .It will not fit down completely in between but I can get it recessed in about halfway .I have not decided exactly where to mount the top of the coilover yet .I do not know what angle I want to put the coilover at yet .It cannot go straight up like the strut because then shock travel would equal wheel travel would equal broken shocks .Have to get the right ratio there .
Looking at the bracket in the last picture , I just realized that using the strut bottom for the base of the bracket is not needed .Since the cam bolt adjustment does nothing any way , I can make a much nicer looking bracket without the remains of the strut in it .I can get all the dimensions I need off the existing bracket .
I have the outer delrin bushings in the machine shop getting the AL bits machined to fit in the DOM tubing I bought at a place called the Metal Supermarket down in Mississauga .Fun little place , great selection and they will sell you anywhere from 6" to 6 miles of just about anything metal .But I do not know if I will end up using the outboard bushings or not .Yarmouth fiero came up with a bracket idea to attach a tie rod to the lower control arm .It looks very simple to make and if I used it instead of a rigid upper control arm I would have more flexibility in control arm placement .With what I am trying to do now , to replicate the up and down motion and placement that the strut creates , I conclude that the arm could only be located in one place with the only variables being the height of the mount on the spindle stub and the upward or downward angle of the arms at ride height .Owing to the space limitations with my engine transaxle combination , the maximum length of the upper arms is 5.5" centre to centre .That is pretty short , but still workable .My wife has a car parked for the winter with a similar length upper rear control arm . Anyway ,if you imagine a line drawn between the ball joint and straight up to the top strut mount , you have a line that you could run an upper control arm at right angles to make something that would move the wheel up and down similar to what happens with the strut .Except that because you have now created an unequal length upper and lower control arm suspension ,it follows an ellipse rather than a straight line .The problems inherent in this design of mine are that if you look at the strut stub without the strut on , the line it follows appears to lean towards the front of the vehicle .So if you want anti squat , the angle of my arms is actually backwards . The other strange thing has to do with the angle deviation from longitudinal of the factory lower control arm mounting points vs the angle of my control arm inner mounting points .Keep in mind that for my upper arms to maintain the toe constant they have to be lineal and parallel to each other .So direction of the line drawn between the inner bushings of the upper control arms as designed compared to the line drawn between the inner lower factory bushings would form a shallow X rather than an 11 .So I don't think it would be possible to even use suspension software to predict how this would function because who would even think to design it that way ? But the thing is , doing stuff like this is my hobby .Just because it should not work , does not mean it wouldn't work .But if something easier comes along , who am I to flog a dead horse .I still would like to see how this setup would work , suspension design truly is more of a black art rather than pure science anyways , but I am going to change direction here .If I use Yarmouths neat little bracket ,I can use an upper ball joint instead of two bushings and I can angle the arm any way I want and I can make it parallel to the to the lower control arm mounts .And a bonus is that the bumpsteer arms have everything I need to finish the bracket .The trouble with using a spindle designed for a strut is that it has to move up and down in one angle .If you lever the stub fore and aft to change the arm angle , you just lengthened or shortened the cars wheelbase .And if you rotate the stub , you change the toe .It limits your options .So the next time I post , you will see something completely different .Might be a while .
I have been busy reading my suspension book and have established some basic dimensions and angles and a path forward .Looking at my old bumpsteer arms , not only can I salvage the parts needed to make a Yarmouthfiero bracket , the bracket itself can be made from a part of the arm . If you look at the square pivot bar that is bolted in where the lower ball joint should be , you can see that I can cut it to bolt to the ball joint pinch bolt and then cut the post that bolts to the tie rod arm a little shorter. Drill and tap the bar , get a shorter bolt for the tie rod arm and I will have my bump steer bracket .
I tried making a bracket out of the bumpsteer arm but that did not workout very well .That and the fact that the finished product was going to weigh over 5 pounds made me decide to attempt making one from scratch .It is a variation of what Yarmouth drew up .I have not carved it up to make the rod end mount yet .I need a ball joint to measure so I get the hole in the right spot and I don't want to mess up the ones on the arms now .CDN tire showed 0 stock in the warehouse so I will try one of the local parts guys on saturday . There is a corner gusset and a back side brace that will be added next time I get a chance to work on this .
[This message has been edited by wftb (edited 02-05-2015).]
Got a little more done on the bumpsteer arm .I was looking at how I could brace it up some more , and I realized the spindle has sort of a natural brace built in to it : I ground a flat spot on the little wing (I think it was a steering limiter for the front of an X car , does nothing on the rear of a fiero ) The corner bracket butts up against this wing and that will prevent the brace from bending out .I have found that the spindle you are looking at is garbage .It looks like it was driven with a loose or broken cinch bolt and it is too sloppy to use .No matter how much I tighten the bolt , the ball joint stud stays sloppy .I traded member Lunatic 4 spindles for a GT wing and I found a better one that fits nice and tight .But now I have to change my new hub over to that spindle .On the bright side , I can do a better job of carving the wing to give better support for the brace .
Now that I have been forced in to working with a bone stock spindle , I realize there are more ways to brace this piece than I first thought .If you leave the steering stop mostly as is and just grind off what you need to fit your brace in , you can drill and tap a hole and bolt directly to the spindle .I added another small brace and welded everything up and I think I have a mount that can not bend or twist now .