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Thread: A Corner Ballancing Story.....

  1. #1
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    Default A Corner Ballancing Story.....

    I did a corner ballance on the Z3 last Saturday. I'd planned to install 45lbs of weight. I didn't bolt it down in case I needed to move it. Well when I finished I had 695 on the LF and 696 RF, but my total weight with ~7 gallons in the tank was 2763lbs. So I'll need to add more weight, maybe ~ 20lbs should be enough. I guess I'll have to redo the corner balance. Oh yeah, Front/Rear was 50.2/49.8, I guess the car's a tank if it could take the roll and still be this close on the corner ballance
    STU BMW Z3 2.5liter

  2. #2
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    Try putting 165 pounds of balast in your car! I've got that and still struggle to hit 3055 :-(
    BenSpeed
    #33 ITR Porsche 968
    BigSpeed Racing
    2013 ITR Pro IT Champion
    2014 NE Division ITR Champion

  3. #3
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    Quote Originally Posted by benspeed View Post
    Try putting 165 pounds of balast in your car! I've got that and still struggle to hit 3055 :-(
    psh.. 165.. that's nothing!

    200 in the MR2, and if they do move the 99 si to ITA it would require so much weight ~400+ that we won't run it.
    Track Speed Motorsports
    http://www.trackspeedmotorsports.com/

    Steven Ulbrik (engineer/crew/driver)
    [email protected]

  4. #4
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    How about a fire system or an Accusump placed dead denter in the car?

  5. #5
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    I don't think he was complaining about the ballast, he was showing off how well-balanced the car is.
    Josh Sirota
    ITR '99 BMW Z3 Coupe

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    Quote Originally Posted by joeg View Post
    How about a fire system or an Accusump placed dead denter in the car?
    I've already got a fire system... I could use an accusump, or maybe a suit cooler.

    Josh, pretty much nailed it

    Though I have to wonder how much reinforcement is needed. Also, has anyone used RTV between the plates to keep the weight room sounds to a minimum?
    Last edited by Z3_GoCar; 05-10-2010 at 11:53 PM.
    STU BMW Z3 2.5liter

  7. #7
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    Quote Originally Posted by Z3_GoCar View Post
    Josh, pretty much nailed it

    Though I have to wonder how much reinforcement is needed. Also, has anyone used RTV between the plates to keep the weight room sounds to a minimum?
    Betcha that isn't legal per 9.1.3.L but I would also think that if you fasten them properly, you wouldn't hear any noise, no?

    Nice numbers. I especially like the front L-R numbers. Some people shoot for the best possible cross at the expense of throwing the LF-RF out of whack - and then they wonder why they get lock-up in a straight line...
    Andy Bettencourt
    New England Region 188967

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    Quote Originally Posted by Andy Bettencourt View Post
    Betcha that isn't legal per 9.1.3.L but I would also think that if you fasten them properly, you wouldn't hear any noise, no?

    Nice numbers. I especially like the front L-R numbers. Some people shoot for the best possible cross at the expense of throwing the LF-RF out of whack - and then they wonder why they get lock-up in a straight line...
    Two 1/2" grade 8 bolts per stack with grade 8 washers, the largest stack is five 10lb weights, the second is a 10lb and two 5lb'ers. So what additional reinforcement should I use maybe some 1/8" plate?
    STU BMW Z3 2.5liter

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    So, I went back to Walmart and got an additional 25lbs of weight plates, for a total of 70lbs. I'm glad I asked for the re-evaluation of this car because I'm not installing an additional 30lbs. Before I started drilling holes I decided to move my fire bottle closer to the tunnel to allow the weights to be closer to the outside. I put the 50lb stack to the rear, and the 20lb stack just ahead. Then I started the ballancing again. When it was close I went ahead and marked then drilled the holes, bolted the weights in place, and futzed with the corner balance one last time. The results with a full 12 gallon tank are 2818lbs total, so I can use all but about the last 3 gallons of fuel and make weight. The final corners are: LF: 700lbs RF: 700lbs RR: 700lbs and LR: 718lbs. So, I'm starting out slightly tail heavy, but by a half tank I'll be a little nose heavy. I've also decided to go back to the oe sway bar on the rear, it's tiny like about a 1/2" bar, but it'll allow me to continue running my 550lbs/in rear springs instead of purchasing a set of 600 or 650 springs. I was running with out the rear bar, but I think the car was running a little tight, while the adjustable bar I was running on full soft was a little loose. My next race is this weekend, I'll be running ITR and STU, wish me luck :026:
    STU BMW Z3 2.5liter

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    Thanks to all who wished me luck because I scored my first first, in STU. It was a well fought race aginst David Allen in an e-30.

    [ame]http://www.youtube.com/watch?v=6Rh3iJo3r5A[/ame]
    STU BMW Z3 2.5liter

  11. #11
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    Here's some laps from my ITR win:

    [ame]http://www.youtube.com/watch?v=cWJHPOaI0-E[/ame]

    What you won't see is my car overheating ending my weekend. I've since pulled the head and discovered a very slightly burned head gasket.
    STU BMW Z3 2.5liter

  12. #12
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    Quote Originally Posted by Z3_GoCar View Post
    Two 1/2" grade 8 bolts per stack with grade 8 washers, the largest stack is five 10lb weights, the second is a 10lb and two 5lb'ers. So what additional reinforcement should I use maybe some 1/8" plate?
    Yes - or at least 1/16" When I used to have weigh in my car (200 lb. or so) I used a rectangular plate that was about 8" x 3", with the two mounting holes about 5" apart (the weights were made about 10" x 6" and came from a stock car shop and were pre-drilled). Underneath the floor I used large and strong fender washers.

    You don't want that s&*t coming loose when you roll the car!
    timo

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