Installed Metco UCA install with BMR diff. bushing

Discussion in 'Suspension and Chassis' started by drano38, May 17, 2019.

  1. drano38

    drano38 Wayne

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    About a month ago I finished the Metco UCA and bracket install, along with the BMR poly diff bushing kit.
    I like how the Metco UCA has a pivot assembly for the yoke to prevent binding.
    I used the high bracket hole location due to BMR Kelly's posts on various web sites/forums. (Metco instructions say use the low hole for a lowered car).
    Luckily I was able to remove the stock UCA/bracket and get the new one in without lowering the gas tank or remove any of the Whiteline WATTS link pieces (although some of the ratchet swings were extremely limited).
    Cleaning the stock rubber/sleeve out of the diff was pretty easy. I used a Harbor Freight 2" cup brush that I trimmed the flared part of the cup off so it would fit into the diff sleeve - it ripped the remaining rubber out of the sleeve with ease.
    https://www.harborfreight.com/wire-wheelcup-brush-set-6-pc-60475.html
    After install, I put the axle on jack stands to load the suspension, and adjusted the UCA length for driveshaft pinion angle (although not critical since DSS uses a CV joint), and the CV housing to shaft length that DSS calls for.
    Overall it feels good after a couple weeks of driving to work and some good turns and acceleration onto Interstate on-ramps.
    No noticeable NVH change.
    IMG_20190419_200401779.jpg
     
  2. xr7

    xr7 Overdosed on TMO

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    I've been interested in that Metco part but couldn't find anyone that had installed it. Excellent write up!
     
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  3. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    Metco has historically been into suspension mods for the straight line crowd, so they're going to be more oriented toward the rear suspension's side view instant center and raising the anti-squat value than keeping rear axle roll steer from going oversteerish.

    Doesn't mean their parts can't work in a corner-carving environment, and you ought to be more than assured that they'll be strong enough for most any road course use.


    Norm
     
  4. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    This is is good to know, thanks for sharing. It's the only way I'd find it acceptable to use poly for handling applications.

    How freely does it move/spin?
     
  5. drano38

    drano38 Wayne

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    It turns pretty firm. It's inside that big block of steel where the yoke narrows down and welded on. Can't take it apart to see how its built because the screws are spot welded in place. The hex nut just in front of the yoke is turned to adjust UCA length, then locked with the big lock nut.
    I'd say its sorta like once a blue locktite bolt is broke free, but the residual drag of the locktite continues to resist the bolt turning.

    Norm, as I was installing this, I read more on the 'net about UCA angles -- wow, everything affects everything!
    If my angle measurements are accurate, my UCA is ~ 13.5 degrees nose-down to the Kenny Brown jacking rails welded to the inside of the pinch welds. Don't know if that is good, bad, or otherwise.
     
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  6. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    UCA is only half of what you need in order to determine where the rear suspension side view instant center is located. And it's the SVIC that determines the anti-squat percentage and the side view swing arm length (SVSA), which are more useful things to know than the arm inclinations themselves. SVSA is linked to how fast the anti-squat percent changes as the suspension moves. Longer SVSA and slower rates of change in anti-squat seem to be generally preferred over shorter/faster.

    It's not hard to calculate where the SVIC is if you have fairly careful measurements to where the LCA and UCA pivot points are. Vertical (referenced to a flat, hard surface) and arm lengths are enough, with a little trig.

    (most drag racers call SVIC "instant center" because they don't care about front view ICs)


    Norm
     

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