I bought new struts when I installed my lowering springs in the rear. They are the stock struts with springs that are 3/4in lower, so not much. However, the second I go over a bump the car acts like it has no shocks at all. The back bounces back and forth so much I literally have to stop.
Do I need to buy different struts? How would I even find struts that are correct with the lowering springs?
I bought a pair of KYB KIT234005 GR-2 / Excel-Gs, the only ones available on rockauto. (Also the same struts I had previously)
Yup! the car is alligned.
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Originally posted by fierosound:
OK... this is an odd one, so bear with us.
What year, and was any other rear suspension work done? Does the car move much if you stand in the trunk and "bounce it"?
Thanks for helping!
Its an 87 with a 3800SC in it.
A TON of work was done, literally everything. I removed the whole rear suspension and had it powdercoared. This mean new tie rods, cradle and a-arm bushings, balljoints, brakes, springs, and struts all around. (New stab links in the front as well)
And that last question is why this is so weird for me! I can move it just like before. I can push it down and back and forth and it pops back up but immediately stops like there is nothing wrong..
OK... so it's not a case of "I installed new struts and springs and now it won't ride right..." LOL
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Originally posted by Threedog:
I can move it just like before. I can push it down and back and forth and it pops back up but immediately stops like there is nothing wrong..
Did you torque the rear control arms bolts properly to 66 ft-lbs? There is such as thing as too tight which would prevent the suspension from responding quickly.
Put a jack or stand under the control arm to support the weight of car before tightening. It's important to have torqued all bolts properly on all the front components for proper suspension response as well.
[This message has been edited by fierosound (edited 05-16-2020).]
Lowered cars w/ cut OE springs, spring saddle mods (like adjustable lower saddle) or aftermarkets springs often have 1 or both of these problems...
Springs are too stiff or too soft causing handling and ride problems. Springs allow struts/shocks to hit End of Travel for them causing same. Worse, This can or more likely will quick destroy them.
Vendor claim will work w/ OE struts/shocks are often lairs.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Lowered cars w/ cut OE springs, spring saddle mods (like adjustable lower saddle) or aftermarkets springs often have 1 or both of these problems...
"often"? Perhaps, but certainly not always.
I have cut springs on the back of my '84, and Fiero Store lowering springs on the back of my Formula. Both cars have Monroe Sensa-Trac struts in the back, and both cars handle and feel great. (Yes, the front of each car is lowered as well.)
I bought new struts when I installed my lowering springs in the rear. They are the stock struts with springs that are 3/4in lower, so not much. However, the second I go over a bump the car acts like it has no shocks at all. The back bounces back and forth so much I literally have to stop.
Do I need to buy different struts? How would I even find struts that are correct with the lowering springs?
If the car is rocking so bad that you have to stop, because it feels like it has no shocks, the struts are not working and that's a very dangerous condition. I lost my younger brother to an accident in a car with one of his friends, who for whatever reason was driving a car with the shocks removed and while doing so, made contact with a vehicle driven by another friend, causing the car to bounce and oscillate uncontrollably resulting in a rollover crash.
The shocks and struts are in place to prevent exactly what is happening, and if they're not doing so, they're not working because they're defective in some way, or they are out of their designed function range. I used KYB struts that I modified for coil over use by removing the spring seat and had the car lowered as much as an inch and a half with no such problem.
The struts and shocks are Fiero specific so there's no telling how long they've been sitting on a shelf.
[This message has been edited by Joseph Upson (edited 05-16-2020).]
When I purchased my current Fiero I took a trip in the rain and the car was sliding all over the road. On the return trip bump steer became a problem. Aligned it and it steadied the car,. but when hitting larger bumps it still did create some bump steer. Added the Addco anti-sway bar set and handling is now what it should be. My point is to first check alignment but if you use a spring where the rates are way off stock and the travel is less, that could have a bearing. The first question is after installing the coil overs, did you have the car aligned?
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 05-16-2020).]
Physically riding on bump stops... this happens all the time where people do not verify suspension travel range of motion for desired stance. When you ride on the bump stops, you have virtually zero suspension travel, no shock/strut dampening control, and the car bounces based on the tire sidewall stiffness.
Riding on the end of motion of the shock and strut. I see this all the time... If you remove the springs and bump stops from a Fiero suspension and raise the wheel as high as possible, the shock and strut will bottom out before the tire is within an inch of the fender/top of wheel well. So if you target a 2" fender gap, you have 1" of shock/strut travel and you will bottom them out. If you target 1" or less fender gap, you will be riding on the shock/strut bottomed out. Depending on how much travel you have, this could be a slamming sensation where you have some travel and then hit the limit, or just constant bouncy like riding on the bump stops (because you are). This is why most flip the rear strut hat (on 88s and fastbacks) and alter the front shock mounting point with spacers (88s) or relocating holes to maximize the available travel. This is more of an issue in the rear if you didn't install new bump stops with your new strut
Worn shocks/struts - zero dampening. This will have large amounts of body movement and will oscillate at a much slower rate will will take a long time to settle down after a bump (6+ oscillations)
Springs to stiff for shocks/struts to properly dampen. This is normally found after a bump where it takes several 3-5 oscillations to settle down. Stock front and rear spring rates are about 145 (88) to 195 (84-87) and 145 (88) and slightly higher for the 84-87. Going with 350+ lb springs will be an issue with dampening control. 300 lb/in normally isn't too bad with the KYBs, but I recommend a lot of 250 lb/in rear coilovers.
OP isn't the first one to complain about the ride with the eibachs as several sets of the coilovers I have sold were to replace poor riding eibachs. I haven't ever had the eibachs to measure spring rate, but I suspect they are 350+ spring rate
I have also ran across one brand new KYB strut that had about 2-3" of free movement w/o any dampening effort. So event new parts can be bad... that is why it is good to check prior to install.
Are the strut pinch-bolts at the strut-to-knuckle joint fully tightened? Those can cause serious handling problems resulting in loss of control of the vehicle if they're not tight, particularly the lower one. I have experienced alignment shops forgetting to tighten one or both of these bolts sufficiently. The car can drive fine in a straight line on a smooth road, but as soon as the suspension starts to move, the joint slips and the car is all over the place.
ETA: wftb replied while I was typing
[This message has been edited by Will (edited 05-16-2020).]
Dang-nabbed double posts- I always kill Pennocks window and then re-enter after doing a post (Hitting back button causes double posts)
Couple of things, some of which has been stated....I was driving Redwood road, chasing some MCs, and hit a big dip which caused my car to bottom out- once started it kept hopping until I stopped- there was no damage to the sturts, just bottomed out and started hopping. I then started working on increasing the amount of travel before hitting the bump-stops; Eliminated the normal Fiero bump stop and cut down the top of the strut to allow some entry into the bump-stop housing at the top...Now I have approx' 2.75-3" of upward travel before it hits the smaller rubber bump-stop up inside the top bracket
Next up, had a problem driving home across bridge; If I hit the gas, it would pull to one side, if I let off or hit the brakes it would pull the other way...Inspecting everything, I noticed that one of my GR-2s was wet- oil! Leaking....I had had Arraut convert them to coil-overs and possibly at that point he cracked one while removing the spring seat. If you have this weird problem, check your struts; I pulled mine off and that left one could be pushed down but would not return up- loss of gas pressure and some of the fluid. What I am saying here is, make sure your struts are working and properly filled/pressurized. Take them off and push 'em down, then watch- within a few seconds they should extend back up.
Third, while driving home after the Redwood road fiasco, I noticed the car was driving very strange- the camber had changed from all of that hopping......So check your alignment.
Physically riding on bump stops... this happens all the time where people do not verify suspension travel range of motion for desired stance. When you ride on the bump stops, you have virtually zero suspension travel, no shock/strut dampening control, and the car bounces based on the tire sidewall stiffness.
Riding on the end of motion of the shock and strut. I see this all the time... If you remove the springs and bump stops from a Fiero suspension and raise the wheel as high as possible, the shock and strut will bottom out before the tire is within an inch of the fender/top of wheel well. So if you target a 2" fender gap, you have 1" of shock/strut travel and you will bottom them out. If you target 1" or less fender gap, you will be riding on the shock/strut bottomed out. Depending on how much travel you have, this could be a slamming sensation where you have some travel and then hit the limit, or just constant bouncy like riding on the bump stops (because you are). This is why most flip the rear strut hat (on 88s and fastbacks) and alter the front shock mounting point with spacers (88s) or relocating holes to maximize the available travel. This is more of an issue in the rear if you didn't install new bump stops with your new strut
Worn shocks/struts - zero dampening. This will have large amounts of body movement and will oscillate at a much slower rate will will take a long time to settle down after a bump (6+ oscillations)
Springs to stiff for shocks/struts to properly dampen. This is normally found after a bump where it takes several 3-5 oscillations to settle down. Stock front and rear spring rates are about 145 (88) to 195 (84-87) and 145 (88) and slightly higher for the 84-87. Going with 350+ lb springs will be an issue with dampening control. 300 lb/in normally isn't too bad with the KYBs, but I recommend a lot of 250 lb/in rear coilovers.
OP isn't the first one to complain about the ride with the eibachs as several sets of the coilovers I have sold were to replace poor riding eibachs. I haven't ever had the eibachs to measure spring rate, but I suspect they are 350+ spring rate
I have also ran across one brand new KYB strut that had about 2-3" of free movement w/o any dampening effort. So event new parts can be bad... that is why it is good to check prior to install.
This is exactly what happens. It is oscillating. Thank you so much!
My first attempt is going to be to cut the bump stops. I did not install new ones that were correct. It would also explain why they car seems not to move a lot when I push down when it is parked. My fear is that if I cut the bump stops a little, it will seem fine for a while but if i hit a big enough bump I may lose control, is that a possibility?
If cutting the bump stops doesnt work, I may go with a new setup in the back completely.
I bought new struts when I installed my lowering springs in the rear. They are the stock struts with springs that are 3/4in lower, so not much.
quote
Originally posted by Threedog:
My first attempt is going to be to cut the bump stops. I did not install new ones that were correct.
I didn't cut the rear bump stops in either of my Fieros, one with a duke and one with the 2.8 V6. Both with 5-spds. Neither car has ever bottomed out the rear suspension. Both cars are lowered at least an inch in the back. (I also flipped the rear strut hats on both cars.)
There may be something wrong with the inherent design/function of the Eibach springs, or with these particular KYB struts (faulty?)... but I find it awfully difficult to believe that just a 3/4-in drop alone could be causing all these issues.
However...
I don't know what tranny the OP's Fiero has, but it does have a 3800sc. Perhaps it's a lot heavier and therefore has issues with these springs and struts that a "stock" Fiero wouldn't experience.
[This message has been edited by Patrick (edited 05-16-2020).]
This is exactly what happens. It is oscillating. Thank you so much!
My first attempt is going to be to cut the bump stops. I did not install new ones that were correct. It would also explain why they car seems not to move a lot when I push down when it is parked. My fear is that if I cut the bump stops a little, it will seem fine for a while but if i hit a big enough bump I may lose control, is that a possibility?
If cutting the bump stops doesnt work, I may go with a new setup in the back completely.
Are you sitting on the bumps stops? I suppose it is possible and should be investigated. Wheels off with weight of the car supported on stands under the control arms to see what's going on.
Originally posted by cvxjet: Next up, had a problem driving home across bridge; If I hit the gas, it would pull to one side, if I let off or hit the brakes it would pull the other way...Inspecting everything, I noticed that one of my GR-2s was wet- oil! Leaking....I had had Arraut convert them to coil-overs and possibly at that point he cracked one while removing the spring seat. If you have this weird problem, check your struts; I pulled mine off and that left one could be pushed down but would not return up- loss of gas pressure and some of the fluid. What I am saying here is, make sure your struts are working and properly filled/pressurized. Take them off and push 'em down, then watch- within a few seconds they should extend back up.
That's often cause by iffy cradle mounts and off-center loading of the "dog-bone." That can twist the cradle thus "steer" the rear axle when you hit the gas etc. Contrary to popular myth even solid mounts for 84-87 and 88 can have this problem if cradle hardware is loose etc.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
