Need advice on my suspension

Discussion in 'Suspension, Brakes & Chassis' started by krishelnino, May 4, 2020.

  1. OP
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    krishelnino

    krishelnino Well-Known Member

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    So this thought popped up in my mind after reading your last post. If the FP front spring rate is indeed linear, then i could probably keep it as is and just swap the rear springs to SP083R? This way i don't have to mess anything at the front of the car. The rear i'll just thrown on the OEM PP/GT350 swaybar to keep the balance.
     
  2. Bluemustang

    Bluemustang Well-Known Member

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    You could. The FP front spring will ride lower, increasing your rake at least another 1/8 or 1/4".
     
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  3. OP
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    krishelnino

    krishelnino Well-Known Member

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    Probably a bad idea, i realized i forgot about the ride height. The SP083 springs have the ride height optimized for geometry.
     
  4. TeeLew

    TeeLew Well-Known Member

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    What's the consensus on the S550 rake sensitivity? In theory, lowering the front and/or raising the rear should reduce understeer. Do people find this to be the case in practice? What else do they find?
     
  5. bnightstar

    bnightstar Well-Known Member

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    I switched my tires to 275/35 all around which made my front to be higher than the rear but this made the car to oversteer.
     
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  6. TeeLew

    TeeLew Well-Known Member

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    That's a little counterintuitive. What tires did you have on the car previously?
     
  7. bnightstar

    bnightstar Well-Known Member

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    I have a PP car so 255/40 Front and 275/40 Back
     
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  8. TeeLew

    TeeLew Well-Known Member

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    Ok, now it makes sense. That extra inch of rubber on each front tire is a big deal.
     
  9. Bluemustang

    Bluemustang Well-Known Member

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    Yeah. The staggered rear is gonna make the car push. Without that, the balance shifts more towards the neutral/oversteer side of scale. Also, even things like tire pressure can change the balance, so depending on his tire psi that can also contribute.
     
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  10. bnightstar

    bnightstar Well-Known Member

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    It does become oversteer so I will buy bigger front sway to push it back a bit. Because I also switched to Semi-Slicks and they are stickier so the car is leaning a lot with them. Next track event is 05.06 which will be my first with this tires.
     
  11. OP
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    krishelnino

    krishelnino Well-Known Member

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    As an update, I've been waiting few weeks since my order but the BMR front 3-adjustable bar is not expected to be available until Jun 20th. So i decided to keep the FP 36.5mm bar at the front for now and set it to stiffer setting. I've also postponed the RLCA bearings and Shock mounts upgrades to couple of months later when I do the diff swap.

    Tomorrow i'll be getting these installed
    BMR SP083
    BMR vertical links TCA048
    OEM PP rear bar
    MGW X-Spec.

    along with this alignment
    F Camber: -2.0
    Toe: 0.05 per side, total 0.10
    R Camber: -1.7
    Toe: 0.10 per side, total 0.20
     
  12. shogun32

    shogun32 Well-Known Member

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    Maybe -1.5 on the rear to match that front? BMR etc recommend more like 0.12-0.15 rear toe per side. Admittedly I don't know how much difference that makes.
     
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  13. Bluemustang

    Bluemustang Well-Known Member

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    I concur. Try to achieve a 0.5 deg less rear camber. It's a good balance, and IMO should work really well with his stiff front sway bar and the SP083 springs.

    Running less rear camber will give lower rear cornering grip, but you need more front anyway, and by running that camber split front-rear it makes the car more lively and helps rid the car of it's terminal factory understeer. However, less rear camber will make it hook up better in a straight line. His stiff front bar will also help plant the rear tires so I think it should come very close to balanced out - giving him a slight understeer at the limit.

    Edit: as a side note, I am planning basically the same thing, only he may end up with a touch less camber overall than me and his front sway bar will be a little stiffer than mine.

    Also, BMR recommends 0.10 rear per side if you have the FP toe/knuckle bearing - 0.12 without.
     
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    krishelnino

    krishelnino Well-Known Member

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    Thanks @shogun32 @Bluemustang, i'll stick to -1.5 camber at the rear then. And for the rear toe, I have the FP toe/knuckle bearing so don't want to go beyond 0.10.

    Also, does the front toe make any difference between 0 to 0.05 ? What are you guys running for street use.
     
  15. TeeLew

    TeeLew Well-Known Member

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    No.
     
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