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Thread: Spring Rates on a Datsun 510 ITC

  1. #21
    Join Date
    Dec 2001
    Location
    SF Bay Area, California
    Posts
    170

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    Quite so, Harry.

    If you've followed the link below to the small web site about our team, you've seen that one of my particular interests has been in the technical side of racing. So it is natural for me to ask questions and test & evaluate.

    So yes, I'll follow Al's advice and look into all those issues. But I'll also recalculate base spring rates for our car based on its actual corner weights. Since the car came with adjustable dampers and anti-roll bars, further refinement is just a matter of testing and evaluation.

    Thanks! Happy New Year All...!

    ------------------
    Stan
    1972 Datsun 510 ITC
    1995 Ralt RT-41 FA
    RPS Motorsports

  2. #22
    Join Date
    Jan 2002
    Posts
    4

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    Hey haven't looked for a while but great! to see 510 talk. I run 250 up front and 1000 in rear. My research shows like said before-stiff in back to limit toe change. As suspension moves up in back toe-in increases and obviously neg camber increases. Stiff keeps toe settings more constant. I have used Dons stuff and been quite pleased(Design Products) he has all spherical bearings for suspension pickup points and sells everything you need for your suspension. First class operation. I use his tublar bars(fully adjustable) and am still trying to dial out ultra high speed oversteer
    otherwise its feeling the way I like it. Would like to start a jetting discussion.
    ITC 13 Mid Div

  3. #23
    Join Date
    Dec 2001
    Location
    SF Bay Area, California
    Posts
    170

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    Yeah, I forgot about the geometry when I first asked the question. Before the season starts I'll scale the car and ensure I don't have any binding and that the spring rates match the actual corner weights...

    So, you have any ideas about jetting the engine off the dyno?

    ------------------
    Stan
    1972 Datsun 510 ITC
    1995 Ralt RT-41 FA
    RPS Motorsports

  4. #24
    Join Date
    Mar 2002
    Location
    ACT, Australia
    Posts
    8

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    Apologies, double post. Can this be deleted pretty please?

    "I love the smell of Avgas in the morning..."

    [This message has been edited by Group3J510 (edited March 03, 2002).]

  5. #25
    Join Date
    Mar 2002
    Location
    ACT, Australia
    Posts
    8

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    Hi guy's,

    I run an IP 510 in Australia. I'm currently running 310lb front's and 780lb rears in my car. The car has very neutral handling - so the balance is good. Stiffer would be nicer, but softer allows you to ride the ripple strips a bit more easily without upsetting the car. Softer also seems to give slightly better feel of the limit of adhesion in the wet in my experience.

    Hope that helps.

    Cheers

    ------------------
    "I love the smell of Avgas in the morning..."

  6. #26
    Join Date
    Dec 2001
    Location
    SF Bay Area, California
    Posts
    170

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    <font face=\"Verdana, Arial\" size=\"2\">I'm currently running 310lb front's and 780lb rears in my car. The car has very neutral handling - so the balance is good. </font>
    Neutral handling is certainly what I'm looking for. Cabn you tell us your corner weights?

    Thanks! Stan

  7. #27
    Join Date
    Mar 2002
    Location
    ACT, Australia
    Posts
    8

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    Hi Stan,

    Unfortuately I can't as I don't have any corner scales (they're around $2500 over here - which is out of my budget). I do have front/rear weights, but not with me (I'm at work atm). I'm working again in 2 days (I do shift work), so I'll bring in my development book and let you know then.

    One thing I didn't mention is that the car does understeer a bit in the wet - although this can be overcome with power oversteer. I've found that this is tuneable with tyre pressures to some degree, but it's an intrinsic part of the handling. If you're running any sort of fixed locked diff (welded, spool, etc) then it'll be worse again. I'm runnning an LSD with 120 lbs of preload and it's been perfect up until now. I've just done some engine mods so I may need to raise the preload, which will in turn change the handling. I've found that running the LSD gives much better turn in than when I was running a locker (welded).....good improvement in handling.

    Cheers

    ------------------
    "I love the smell of Avgas in the morning..."


    [This message has been edited by Group3J510 (edited March 03, 2002).]

  8. #28
    Join Date
    Dec 2001
    Location
    SF Bay Area, California
    Posts
    170

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    If you're running any sort of fixed locked diff (welded, spool, etc) then it'll be worse again. I'm runnning an LSD with 120 lbs of preload and it's been perfect up until now. I've just done some engine mods so I may need to raise the preload, which will in turn change the handling. I've found that running the LSD gives much better turn in than when I was running a locker (welded).....good improvement in handling.
    Hey, thanks for the timely thoughts! I just bought a 3.73 LSD from a Subaru to swap in my 510 in place of the welded 4.10, so your comments will come in handy. I don't know what kind of preload the LSD has, but it's whatever came stock. In any event, I'm running a "blueprinted" stock 1600, so the power isn't overwhelming.

    Lemme know what your front and rear weights are when you get back to work, will you?

    Thanks! Stan

    ------------------
    Stan
    1972 Datsun 510 ITC
    1995 Ralt RT-41 FA
    RPS Motorsports

  9. #29
    Join Date
    Mar 2002
    Location
    ACT, Australia
    Posts
    8

    Default

    G'day Stan,

    Sorry it's taken me so long to get back here, but things have gone a bit awry.

    Anyhow, the weight distribution of the car was until recently 530kg's at the front and 400 kg's at the rear (930kg's total). This was taken with 15L of fuel in the car and no driver or passenger. It was done at a public weigh bridge. The reason I say recently is because I had a steel cage put into the car, replacing the old alloy one, so the overall weight would have increased...although I imagine that the distribution would be pretty much the same. Having said that, as soon as the car is running again, I'll take it to the weigh bridge and measure it again.

    Hope that helps

    Cheers


    ------------------
    "I love the smell of Avgas in the morning..."

  10. #30
    Join Date
    Jan 2001
    Location
    Buffalo, New York
    Posts
    2,942

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    Whatever BADAL says should probably taken as gospel for the 510.

    He is mighty quick with that car.

    Cheers.

  11. #31
    Join Date
    Feb 2001
    Location
    Trussville, Alabama, USA
    Posts
    1,087

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    the oscellations you describe in the front of the car have nothing to do with the springs. the shocks are designed to dampen the movement of the springs. either the shocks are all wrong for the springs, or they are tired and can't control the weight, assuming they are not adjustable. if they are adjustable, increase both compression and rebount dampening one incriment of adjustment until the unwanted actions cease..good racing

    ------------------
    Chuck Baader
    SEDIV ITS #36
    E30 BMW

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