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Thread: High LF weight?

  1. #1
    Join Date
    May 2007
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    Default High LF weight?

    Does this concern any of you guys, when your scaling your race car?

    I notice that LF is unusually heavy, and it affects cross weight, ussually 450 ish RF, and 575 or so LF. Ride heights are good.

    Wedge is like 75lbs in the rear.

    What would cause this? how do i fix it?

    Thanks, Krom.

    Just say no...

  2. #2
    Join Date
    May 2009
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    1,336

    Default

    Whats your percents? High Left Side Percent,
    Quote Originally Posted by Kromulous View Post
    Does this concern any of you guys, when your scaling your race car?

    I notice that LF is unusually heavy, and it affects cross weight, ussually 450 ish RF, and 575 or so LF. Ride heights are good.

    Wedge is like 75lbs in the rear.

    What would cause this? how do i fix it?

    Thanks, Krom.

  3. #3
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    May 2007
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    2,927

    Default

    It was up there about 54% at one time, i got it down to 52% at the end of last year but never got to run the car but the LF weight was still high.

    If that wheel weight is high, the CG of the car has to be closer to that corner? so i need to move weight away from that corner.

    I am thinking about moving the battery, from the normal over the LR spot, to directly across the Driver on the right side.

    Just say no...

  4. #4
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    May 2007
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    Kansas
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    Default

    Quote Originally Posted by Kromulous View Post
    It was up there about 54% at one time, i got it down to 52% at the end of last year but never got to run the car but the LF weight was still high.

    If that wheel weight is high, the CG of the car has to be closer to that corner? so i need to move weight away from that corner.

    I am thinking about moving the battery, from the normal over the LR spot, to directly across the Driver on the right side.
    A heavy LF weight is because of the low Wedge in the car for that given left and rear%. If you want to stay with that wedge you either have to decrease left side% or increase rear %. Or if wanting those %'s then increase wedge.

  5. #5
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    Jun 2007
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    Default

    Bottom line is that if you want the the front tires to weigh the same, your cross weight percentage must be equal to the left side percentage.
    For a 2300 pound car, 52% cross yields 92 pounds of LR bite. 54% would yield 184 pounds of LR bite.
    Personally, I don't think I would like a setup like that. As you increase left side and cross at the same time (which is what you have to do to keep the fronts close), you're freeing up entry quite a bit. I would think a stiffer LF spring would be in order to bring some dynamic balance back.

  6. #6
    Join Date
    Jul 2014
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    Default

    How did you do to get left % down to 52% from 54%?

  7. #7
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    Default

    krom, had a problem like that with a grt, when I had a steel motor in to the left, moved over to right and it helped alot

  8. #8
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    Moved a 25lb weight off the LR frame rail, to just in front of the dry sump tank. Then added another to the RR frame rail.

    I like 92lbs at ride height, and 52 left idea. Maybe 52.5 or 53. Somewhere in that range, What would the rear percent need to be?

    I don't want even, but maybe within 50 to 75lbs would be nice.

    Just say no...

  9. #9
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    Jul 2014
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    Not sure what your after. What L&R and cross % to run? Where to place ballast? To change L & R % you have to move, add / remove weight, or relocate rear axle L-R. How much ballast is on car?

  10. #10
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    Jun 2007
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    Quote Originally Posted by Kromulous View Post
    Moved a 25lb weight off the LR frame rail, to just in front of the dry sump tank. Then added another to the RR frame rail.

    I like 92lbs at ride height, and 52 left idea. Maybe 52.5 or 53. Somewhere in that range, What would the rear percent need to be?

    I don't want even, but maybe within 50 to 75lbs would be nice.
    Okay...I'll ask the obvious question...Why do you want the LF 50-75 pounds heavier than the RF?

  11. #11
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    May 2007
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    I meant to say i like 92lbs LR bite, thats a good number for me.

    The problem i usually see is the cross percentage is hosed up due to the high left front wheel weight. i can never get the cross % to 49 or 50 %. Some people say not to worry about it, but i don't know. That's why the 50lbs split question comes from.

    I am tinkering with LS% in an effort to create more scrub, or right side side bite, that may be all wrong too.

    I have 50lbs on the car now, i will run over weight. We run 2350lbs after race but i dont really care i would rather get the numbers i want.
    Last edited by Kromulous; 02-28-2017 at 08:29 AM.

    Just say no...

  12. #12
    Join Date
    Sep 2007
    Posts
    164

    Default

    Move the weight from the right rear to the center of the car, also move the battery as you describe. Weight in the center of the car isn't too bad and helps balance the car to the numbers you want. Also move the the motor to the right as someone above mentioned. How much does the driver weigh?? His weigh can make a left front heavy condition as well.

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