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Handling question

Steering / Suspension

  1. plymouth67

    plymouth67 Active Member

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    So my car has 17 x 8 wheels on the front, all front suspension is new, freshly aligned but still not happy with they way it drives. I'm wondering what you guys who have bigger wheels on your cars have done to make them drive better. My suspension is stock stuff and I dont really have the money to drop on Alterkation stuff or anything like that but, if there are some control arms or things I could change to make it better I could do that. Thanks in advance...
     
  2. DrEamer

    DrEamer Well-Known Member

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  3. gzig5

    gzig5 Well-Known Member

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    Before throwing parts at it, you have to determine where the problem lies. What does the car do that you don't like?
    What are your alignment specs, specifically how much castor do you have? More positive castor usually feels better on these cars. Is the steering box original? If so it probably can use a rebuild stage 2 or 3 from Frim Feel, or Borgeson conversion. What are you using for shocks? Front or rear sway bars?
     
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  4. Adam

    Adam Well-Known Member

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    https://www.mopar-forum.eu/download/file.php?id=6221

    Control Arm Stiffening plates

    Firmfeel Mopar Suspension and Steering

    With my car I did the low buck “pump it down” mod. This was very worthwhile and I like it a lot. Mopars of that era have too much power steering assist, in my opinion.

    The lower control arms are very strong, up and down, but can twist a little under hard conditions. LCA stiffening plates are a cheap upgrade.

    Also, I would recommend a torsion bar upgrade. New, heavier bars will probably be the most noticeable improvement. (Factory bars had a flexible coating on them. New bars probably don’t, but you can spray them with flexible undercoating).

    Originally these cars had bias ply tires,which were not great for cornering, but performance radials will expose any deficiencies in your suspension.

    If you find you need adjustable upper control arms, I would recommend you bite the bullet and upgrade all your suspension bushings while you have it apart. I like polyurethane because they last much longer than rubber, but others prefer rubber, so you need to read up on it to make an informed decision.
     
    Last edited: Oct 31, 2019
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  5. Ralph

    Ralph Well-Known Member

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    Talk to Dick at Firm Feel. He helped me and my cuda corners like its on rails.

    Good person to talk about your problem and he is soft sell.
     
  6. plymouth67

    plymouth67 Active Member

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    Thanks for all your responses, I guess I should be a little more descriptive on suspension and what it does. It has a new steering box, it has Hemi torsion bars, all new bushings, ball joints, factory sway bar, new shocks. So what I don't like about the way it drives is going down uneven roads it really hunts for where it wants to be. It's fine on smooth roads it turns fine, corners ok, just get the slightest funky surface and its searching.
     
  7. gzig5

    gzig5 Well-Known Member

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    I'm not an expert but more positive caster should help with bump steer? You can get more camber cheaply by using the MOOG offset bushings for the stock upper arms.
    Moog Offset Front Control Arm Bushings

    Another way is the Hotchkiss or QA1 tubular upper arms.

    As stated, these cars are over boosted on the power steering IMO. If you have a Saginaw pump, it can be modified to reduce pressure output and reduce assist. I don't think the Federal pumps are easily modified. Reduced assist should help with feel.
     
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  8. plymouth67

    plymouth67 Active Member

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    I took to a local alignment shop and the guy wanted to say its because of the size of the tires and he didnt think there was much they could do to make it any better. I dont ever remember my 70 driving like this, but it had 15" wheels on it. Just hoping to make it better on uneven roads. Decent roads it's just fine, goes straight, uneven roads it's like a dog sniffing around looking for place to poop...lol
     
  9. gzig5

    gzig5 Well-Known Member

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    May not be anything you can do to eliminate it if everything else is in good shape. I have 18x9.5 wheels with 275 wide tires on the front of my BMW. On uneven or rutted roads, it can be a handful darting around. I think it is the stiff low profile tires following the rough road where with a taller sidewall on a 15" tire will flex and absorb the uneven road.

    Maybe try dropping the pressure in the front to soften them up. Some tires have very stiff sidewalls and some don't. I know the Hankook Ventus V12 are softer and provide a better ride while still handling well.
     
  10. 1972 AAR Cuda

    1972 AAR Cuda Active Member

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    Things I did on my '74 Challenger while upgrading The motor and rebuilding the front suspension:
    Firm Feel power steering box upgrade (this was a night and day difference)
    Added a front sway bar and mounts
    Welded up the k-member (butt weld around the upper and lower halves), added additional supports/stiffeners for the Firm feel box, added doublers to the Torsion bar mount and strut rod mount on the K-member.
    Added doublers to the lower control arm (boxed the arms)
    Switched to the larger tie-rod ends and adjusters.
    Replaced the old shocks (Bilstein if I remember right)
    I was selective on the urethane mount - I think I stayed with rubber for everything (been a while now)
    I am still using stock size tires and rallye wheels.
    The Challenger now drives much, much better than the stock car did.
     
    Last edited: Nov 3, 2019
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  11. gzig5

    gzig5 Well-Known Member

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    Any pics of these mods? Can't picture what you may have done for the torsion bar and strut rod mounts.
     
  12. 1972 AAR Cuda

    1972 AAR Cuda Active Member

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    Here are a couple:
    The idea was to add bracing around the steering box and where the torsion bar/lower control arm mount and strut rod mount to the K-member.
    0DA07F1A-F592-493C-B651-FFB1D1AAB873.jpeg 141998AE-7BCE-4A1D-8FB5-8BF42FC14212.jpeg 2CD49BE6-0AF6-4DB9-BF47-3191590D409B.jpeg C7749370-CE80-492B-A139-BC3D122CE84D.jpeg
     
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  13. DrEamer

    DrEamer Well-Known Member

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    Firm Feel also sells the kit if you are not as resourceful as 1972 AAR Cuda

    Firmfeel Mopar Suspension and Steering
     
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  14. gzig5

    gzig5 Well-Known Member

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    Excellent. I don't know if I'm as resourceful as he, but I've got welders and a plasma cutter and I know where the power switches are.
     
  15. timdp

    timdp Member

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  16. 12sandwich

    12sandwich Well-Known Member

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    Ride height is so critical on these cars.
    Unless it’s perfect, there will be an uneven toe change.
     
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  17. Mastertech

    Mastertech Member

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    Before everyone gets excited about throwing parts at this problem it may just come down to alignment. If you are running radial tires on this car you need to bump the caster way up. In fact you may not even be able to get enough caster for your big tires with the stock suspension. This is the reason for the Hotchkiss upper control arm relocation. Remember this suspension was designed for Bias Ply tires and the original settings will not work with radial tires. It will hunt all over the road just as you describe. Back in the day when I put G60R15 radials on my 72 I had the caster moved to the max with only a small amount of camber and toe. Tracked like on rails at 80 going down the road with one finger on the wheel. If you look up the alignment specs for any Mopar after 1975 they changed significantly when the factory changed to radials across the board.
    And yes check that the ride height is correct. If your torsion bars are not set correctly it will also affect steering. Lowering the car by loosening the torsion bars will cause major headaches.
     
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  18. plymouth67

    plymouth67 Active Member

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    Do you have a specific alignment settings chart you would recommend using on my car? Do you know the factory ride hiegth for a 71 Challenger?
     
  19. Mastertech

    Mastertech Member

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    To set ride height you measure from the lowest point of steering knuckle arm ( point B) to floor and from the lowest point of adjuster blade directly below the lowest point of the adjuster blade. The ride height is the difference between A and B A is always greater than B. Do this with a full tank of gas and jounce the car a few times first. The spec is 1 1/8 inch + or - 1/8. Adjust by turning torsion bar adjuster clockwise to raise and counterclockwise to lower. Jounce before each measurement after adjusting. Set one side at time but then double check both sides to make sure their the same when done.

    Camber spec is Left 0 to 1 degree positive with 1/2 preferred. Right is 1/4 to 3/4 degree with 1/4 preferred.

    Caster for radial tires is 1/2 degree positive to 1 3/4 degree positive, if you can go higher to 2 or 2 1/4 great but usually you can't with the factory control arms. You want both sides the same. This will also increase steering effort and reduce some of the over boosted feel of the power steering.

    The Hotchkiss Sport Suspension system gives these cars modern handling and I think is very good investment. Their upper control arms correct for the factory problem of camber and caster change as the suspension moves up and down. Add some chassis stiffening and you will stick right with any new Mustang or Camaro.
    Let me know how this works out for you.
    Terry
     
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  20. 12sandwich

    12sandwich Well-Known Member

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    Great advice ^
    The only thing I would add. Don’t be afraid to let camber fall a little negative up to half a degree to increase the caster some more.
    Probably corner a little better also, and have more returnability, and the tendency to go straight is better.