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| Lowered suspension makes the rear literally bounce around? (Page 2/3) |
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Patrick
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MAY 16, 01:26 AM
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I'd also double-check that all four cradle mounting bolts have been torqued/tightened properly, especially the two rear ones.
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theogre
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MAY 16, 02:24 AM
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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.
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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)
The Ogre's Fiero Cave[This message has been edited by theogre (edited 05-16-2020).]
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Patrick
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MAY 16, 02:53 AM
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| quote | Originally posted by theogre:
Lowered cars w/ cut OE springs, spring saddle mods (like adjustable lower saddle) or aftermarkets springs often have 1 or both of these problems...
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"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.)
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Joseph Upson
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MAY 16, 04:44 AM
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| quote | Originally posted by Threedog:
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? |
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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).]
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Dennis LaGrua
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MAY 16, 09:50 AM
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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?
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" 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).]
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fieroguru
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MAY 16, 11:42 AM
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Bouncy ride when lowered is caused by 4 things.
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.
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fieroguru
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MAY 16, 11:45 AM
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double post.. [This message has been edited by fieroguru (edited 05-16-2020).]
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wftb
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MAY 16, 11:53 AM
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Many people forget to torque the strut to spindle bolts to 140 ftlbs.
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86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms[This message has been edited by wftb (edited 05-16-2020).]
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Will
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MAY 16, 12:26 PM
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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).]
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Spadesluck
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MAY 16, 01:30 PM
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Edit, I saw that you installed the new struts. Bouncing like that could be from riding on the bumpstops like others have mentioned. [This message has been edited by Spadesluck (edited 05-16-2020).]
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