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  1. #1

    Gts 1997 eibach caps hard koni

    hello everyone, gts 97 I have modified the original suspension. I hardened the koni, I put on the Eibach springs, and I put on the caps. I have a tire size of 315 / 30r18 pirelli pzerorosso. my problem and that In the bends rather fast, the rear go suddenly without warning. do you have any ideas why the rear leaves so sharp?

  2. #2
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    Are you asking why the rear washes out so quickly? Why it’s loose?

    What does “hardened the koni “ mean? Did you stiffen the the rear suspension?

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    And what about the tires? Same size all around? They seem quite narrow for the rear and wide for the front.

  5. #5
    Yes exactly

    - - - Updated - - -

    Quote Originally Posted by Viper98 View Post
    Are you asking why the rear washes out so quickly? Why it’s loose?

    What does “hardened the koni “ mean? Did you stiffen the the rear suspension?
    Yes exactly

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    Ok, so you stiffened the rear. Tooo stiff will do what you are describing.
    I have limited knowledge, but there are many very sharp people here.

    Can you give more specs?

    What are you doing with it:Road race? Drag? Other?

    Spring rates?

    Front and rear tire sizes/offsets/air pressures?

    Other specs?!

    The more info you can supply the better.

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    Hello Mike.

    Sounds like you have what we call a " snap loose" problem. Does the car " snap loose" in the turn when you hit a bump or put a little more steering wheel into the turn say on a decreasing radius turn???

  8. #8
    Thanks for your answer . In short, for oem koni I went with the rears set to setting 2 or one full turn from full soft. The fronts at setting 3 or one and a half turns.I do mountain roads, no circuits. with lowering with caps and eibach springs. i also have offset wedges only for the rear wheels.

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    Quote Originally Posted by Mike 45 View Post
    Thanks for your answer . In short, for oem koni I went with the rears set to setting 2 or one full turn from full soft. The fronts at setting 3 or one and a half turns.I do mountain roads, no circuits. with lowering with caps and eibach springs. i also have offset wedges only for the rear wheels.
    "off set wedges"???? Im guessing your using the offset washer plates to lock in camber and caster and you have factory rubber bushings?

  10. #10
    Enthusiast GTS Dean's Avatar
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    Hello Mike - I'm assuming English is not your first language and we are trying to help. Gen 2 Vipers are prone to snap oversteer - especially if you jump off the throttle suddenly in a turn. Remember to be VERY gentle in this situation. What model Koni's do you have - 2812? What spring ratings? Careful experimenting with shock settings will help you. Rear wheel caster alignment is critical to a controllable back end. If it is not positive and equal on both sides, you will have different handling in right and left turns. Please be as specific as you can with your modifications.
    96 GTS. Viper Days Modified Class. Fresh motor 10-2020!

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    Mike, you have very stiff and shorter EIBACHS on the rear.

    You say you hardened the OE Konis, but only 'two or one turn from full soft.'

    Do you mean clicks? Do you feel the click-stops? (not full-turns, but ratcheting click stops?)

    Becasue the rear adjustment is TOO SOFT, and lowered, rear is bottoming out and washing out on hard-G-force turns, especially on public roads with bumpiness. You must adjust (harden) the Konis to 3 or 4 clicks away from FULL HARD.

    Rear tires size and age is important

    This all assumes you have good rubber, not old, properly inflated. Car came with 17" wheels. 315-18 at front is +4 wider than stock. Exaggerates snap-oversteer as Dean says.

    Or do you have 18" rears now? Or 18F 19R '?

    Good Luck
    Last edited by JonB ~ PartsRack; 10-25-2021 at 04:57 PM.
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  12. #12
    Thank you for your answers and I am sorry for my English which is not easy to understand.

    my tires are 285 in front and 315 in the back.

    for the Koni suspensions they are original (blue color ?)

    to regulate them I have clearly told on the ''click''.

    adjust them harder ? but I saw on the adjustment on the internet that it should not be too hard at the rear because it should let ''work''.

    I have the front and rear lowering caps and the shorter front and rear Eibach springs.



    so according to you it is necessary:



    harden the back, ok but by how much?



    change the tires from 315 to 335 ... OK

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    My 2000 Viper is on stock Koni shocks(Non ACR). The Damping is set 3/4 stiff, stock springs but on lowering caps. My rear end is very controllable.
    Tyres on the front are Toyo R888 Proxys, 295 x 30 x18. Tyres on the back are 335 X 30 X 18 also Toyo R888 Proxys.

    It seems to me your rear tyres are too Narrow, Stock size is 335 on a 13 J width wheel.

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    Quote Originally Posted by Mike 45 View Post
    Thank you for your answers and I am sorry for my English which is not easy to understand.

    my tires are 285 in front and 315 in the back.

    for the Koni suspensions they are original (blue color ?)

    to regulate them I have clearly told on the ''click''.

    adjust them harder ? but I saw on the adjustment on the internet that it should not be too hard at the rear because it should let ''work''.

    I have the front and rear lowering caps and the shorter front and rear Eibach springs.



    so according to you it is necessary:



    harden the back, ok but by how much?



    change the tires from 315 to 335 ... OK
    No worries Mike your English is good.

    1. If your car is loose ( rear no grip) do not harden it ( add compression ......+ compression) adding compression will simply make problem worse. Take compression out make it softer ( -compression). You can also disconnect rear sway bar if you need to. Usually we only do this in rainy or very low traction conditions but it also works to help diagnose problems.

    2. If your rear goes suddenly ( snap loose) you most likely have a mechanical issue. Roll bind, no bump stops or incorrect bump stops, much to low a spring rate, variable rate springs, shocks need rebuild.

    If the terms I used dont make sense Mike or your not sure let me know and I can explain them.

  15. #15
    Enthusiast nrs1's Avatar
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    At one time I had the Eibach springs (progressives) on my 97 with the caps and stock Konis. My stock shocks were rebuilt and revalved, so the settings would not be the same, and I don't know where they were set, since the suspension engineer set them. But I had the Eibach progressive springs measured and here are the rates: Front 257 lbs - 343 lbs (progressives get stiffer through their travel) Rear 383 lbs - 800 lbs
    97 B/W GTS, Cordes Performance Racing built, Greg Good H/C, StopTech BBK, MCS suspension, Autoform Aero

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    If Mike 45 is running eibach progressive springs this could also amplify the " snap loose" problem. Progressive springs are just fine for getting ride comfort and easy driving street use. But for track setups or more aggressive street use they can cause stability problems.

  17. #17
    Ok you say disconnect rear sway bar . It s not dangerous ?

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    Quote Originally Posted by Mike 45 View Post
    Ok you say disconnect rear sway bar . It s not dangerous ?
    Hello Mike 45
    No not dangerous to disconnect rear sway bar. You only need to disconnect one side and make sure the down link is completely removed......... Or out of the way and secured with zip tie.
    It would be good to get more information from you about your setup to help diagnose and improve your problem.


 

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