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Fiero Front Suspension coilover conversion

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  • Fiero Front Suspension coilover conversion

    I thought I would post in Technical section about my thoughts on how to replace the 84-87 front suspension with a coilover setup. These items are what I more or less did when I built my custom front cross member. I don't know if this will work the same for the '88 as the control arms are different but there shouldn't be too much difference. I don't know that though as I have not tried this on an '88. Mine was built on an '85.

    My thoughts only and shoudl you decide to use this, I do not provide any explicit or implied warranty. use at your own risk and knowledge.


    I recommend you use the oem Fiero cross member and make new wider control arms for the front suspension. With what you are doing with the frame, you can obviously weld so why not make your own widetrack? If you want you can tack it all together and then take to a welder if you are not 100% on your welding. That is what I did way back when I did my front suspension.

    The aftermarket widetrack use a 1.5"+ DOM thick walled tube and then a smaller bracing arm to go back to the oem Fiero rear mount. I don't recommend doing a full cross member like I did as that is way too much work for what you get in the end. Trust me.....

    These instructions are to replace oem Fiero front control arms with tubular control arms and coilover shocks:
    • Get some poly bushings that will fit in both the front cross member pivot and the rear pivot
    • Get the round tube that fits over the poly bushings
    • Get ball joint mounting plates that you will use for the outer ball joint location on the new control arms
    • Take all your oem Fiero control arms off and lay the lower control arms to start on a flat surface so you can see the angles of the control arm
    • Mark the locations of the Fiero control arm pivot mounts.
    • Make some mounting tabs that you can secure to your flat surface to locate both mounting locations
    • Secure the tabs to the workspace and put a bolt through the oem control arm pivot mounts
    • Mark the location of the ball joint on the workspace.
      • Make sure you mark both width out and location in relation to the mount points so you have an accurate location of the ball joint.

    • Measure the distance up off the workspace to a repeatable reference on the ball joint.
    • Measure the angle of the ball joint plate relative to the workspace
      • You will need both of these to relocate the new ball joint plate further out
      • Maybe also make a jig up that will place the ball joint and plate in the same location/orientation for the ball joint so you can use that in the new, outward location

    • Once you have these measurements and the pivot points are securely fixed to the work space, remove the Fiero control arm
    • Now measure outward to the control arm width you want
    • Place the new ball joint jig and plate/ball joint out over the new location and secure it to the workspace
    • Mount your new front and rear poly bushings to the mount locations.
      • You now have the three important locations for your front extended control arms.

    • Take whatever round tube you are comfortable with and fit between the front mount and the ball joint plate
    • Bend the tube to set the proper angles etc. for the ball joint plate
    • Once you have the front/main control arm tacked in place, make a rear stabilizer to connect the mount piece to the main control arm tube
      • The rear stabilizer on the aftermarket units has an adjustment capability to lengthen or shorten the rod to allow for some fine tuning of the suspension positioning.
      • You can also do this if you wish.

    • Tack everything together and do the same on the other side.
    • Do the same procedure for the upper control arms extending them the exact same amount out as the lowers to maintain the hub mounting geometry
    • You now have extended control arms but no shock mounts....
    • Coilovers will vary a bit depending on which ones you end up buying to start with
      • My shocks were longer than the usual suspects so my upper shock mount ended up being different.
      • If you get the shorter shocks, I think the 8" length fits nicely in the Fiero control arm area then you can use the list below

    • On the upper Fiero cross member you will see an additional plate that holds the bump stop, upper control arm and mounting tube.
      • This next part is important as you need to make sure you set up the upper control arm mounts the same to ensure you end up with the same antidive angles

    • Take the upper mount plate off the cross member
    • Make up jigs on your work surface that positions the upper control arm mount tube solidly in the jigs.
    • This ensures the same anti dive angle etc. on the new plate you are going to build
    • Set up a jig to accurately align the five mounting holes on the plate.
      • Two in the bottom that connect to the cross member and three that connect to the wheel well on the frame

    • Once all these are set up and confirmed as accurate, remove the Fiero mounting plate and build a new plate that places the mounting tube and mounting holes accurately in the new mount plate.
      • I used 1/8" flat plate but I have seen 1/8" thick angle iron also used for the upper mounting plates

    • Once the plate, control arm tube and mounting holes are done, you now work on the upper shock mount
    • I put all control arms on to the cross member and set up everything so it was nice and level and secure to mount the coilovers
    • Set the coilover to the centre of the travel using the adjusting screw for the coilover as this will be the final location of the shock when mounted and the car is at your desired ride height.
    • This is where you can place your control arms and mount plate on to the Fiero and put your tire on the hub and rest it on the ground and adjust the car height with a floor jack.
    • Once you have your ride height set to your satisfaction, secure the lower control arm in the desired location and take the tire off.
      • You now have access to the suspension and you can place the coilover in the control arms and measure where you want the coilover to be placed relative to the suspension.

    • Tack in a lower control arm tube between the two control arm tubes at the location out along the lower control arm where the lower mount of the coilover will be
    • Tack on the lower shock mounting plates to that cross piece
    • Put the shock into the lower control arm shock mounts and place the coilover where you want it at the upper mount location.
    • Tack in your upper coilover mounting plates to the upper control arm mounting plate.
    • Next you now add in a plate to mount your sway bar links.
    • The plate should be set up pretty much to butt up against the coil over cross tube and the front control arm tube.
    • Cycle the suspension to each end of the coilover length to make sure you still have full clearance.
    • Take the new suspension parts off the car and finish tacking everything.
    • Do the same thing for the other side using the positions and measurements for the side you just finished
    • Take your parts to a welder or trust your own welding and finish up the welding of all the parts.
    • Last item is to put it all together and cycle both sides through full suspension travel to make sure nothing has moved during welding.
    • You have, as an option, to make a bump stop and that can be done wherever you feel is acceptable and doesn't interfere with the travel or tire/rim.

    That is about it for my thoughts. I will make up some drawings for the jigs and mounts etc. when I get a chance.

    308 Ferrari replica
    Prova Countach 5000S

  • #2
    Thanks Don for taking the time to write this up. -Vinny
    Remember, there is always next year.


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