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Thread: 240z

  1. #1
    Join Date
    Feb 2001
    Location
    Atlanta, Ga
    Posts
    631

    Default 240z

    Ok, how do you detemine spring rates. I bought a pre-built car and the current springs have no markings whatsoever. The fronts are blue and the rears are a chrome color. These actually match what was on my old 240z but its been 10 years since I monkeyed with the springs on that car so I don't remember.

    I've been going over katman's posts on suspension setup and looking to work with a baseline on the car, but that's difficult with unknown spring rates.

    Are hyperco springs color-coded?

    Where's a shop in Atlanta that can test spring rates? Landrums? Robinson Racing?
    Thanks,
    Tom

  2. #2
    Join Date
    Nov 2005
    Location
    Rocket City, Alabama
    Posts
    607

    Default

    Tom,

    You might get lucky and have the rates scribed on the top/bottom of the coils themselves. I know on my old hypercoils there was only a tag wrapped around a coil that easily is knocked off. Eibachs are only painted on that I know of. I have started using a cheap vibrating scribe to note the rates on the top and bottom flat part of the coils.

    John Williams may be able to point you to someone with a spring rate tester.

    Paul
    Paul Ballance
    Tennessee Valley Region (yeah it's in Alabama)
    ITS '72
    1972 240Z
    "Experience is what you get when you're expecting something else." unknown

  3. #3
    Join Date
    Feb 2001
    Location
    Atlanta, Ga
    Posts
    631

    Default

    Thanks Paul.
    I looked at the tops and they're pretty scuffed up and unintelligible. So I'll try the testing route next. As far as springs go, how do hyperco, eibach and landrum compare?

    Tom

  4. #4
    Join Date
    Jan 2001
    Location
    Atlanta, GA usa
    Posts
    677

    Default

    Tom, I don't have his number handy, but you can try giving Dick a call at Magna Shock in Chamblee (formerly Carrera shocks) and see if he has a spring tester. just an idea.
    Tristan Smith
    1991 Nissan ITR 300zx #56

  5. #5
    Join Date
    Feb 2001
    Location
    Atlanta, Ga
    Posts
    631

    Default

    Tristan,

    Thanks, and that's not for from where I work.

    By the way, the 300 looks great. What colors are you going to paint? Red White and Blue?

    Tom

  6. #6
    Join Date
    Mar 2001
    Location
    Acworth, GA USA
    Posts
    455

    Default

    Spring Rate, K = (G*WD^4)/(8*Ne*Davg^3),
    where G = 11,000,000
    WD = wire diameter
    Ne = number of effective coils
    Davg = average diameter (ID+OD)/2 or OD-WD
    You have to take a wag at the number of effective coils, but for most springs that are ground flat on the ends there's about 3/4 coil on either end NOT effective, so count the total number of coils and subtract 1.5.

    Or, you could stand on them and divide your weight by how much the spring compresses.......or if you were worried about breaking your ankle with that method just go see Harry Robinson.
    katman

  7. #7
    Join Date
    Feb 2001
    Location
    Atlanta, Ga
    Posts
    631

    Default

    Quote Originally Posted by kthomas View Post
    Spring Rate, K = (G*WD^4)/(8*Ne*Davg^3),
    where G = 11,000,000
    WD = wire diameter
    Ne = number of effective coils
    Davg = average diameter (ID+OD)/2 or OD-WD
    You have to take a wag at the number of effective coils, but for most springs that are ground flat on the ends there's about 3/4 coil on either end NOT effective, so count the total number of coils and subtract 1.5.

    Or, you could stand on them and divide your weight by how much the spring compresses.......or if you were worried about breaking your ankle with that method just go see Harry Robinson.
    Keith,

    Or, you could just keep scraping the rusty spot until you finally see a number scribed on the spring. Took awhile, but I found it. Now I have to go see Harry anyhow to get that knee bar installed that you and Chet pointed out about 8 years ago.

    Glad you're still around.

    Thanks,
    Tom

  8. #8
    Join Date
    Jan 2001
    Location
    Atlanta, GA usa
    Posts
    677

    Default

    Quote Originally Posted by Tom Donnelly View Post
    Tristan,

    Thanks, and that's not for from where I work.

    By the way, the 300 looks great. What colors are you going to paint? Red White and Blue?

    Tom
    Thanks Tom,
    Well if you go over there, see if someone will bring you over to my car. It's in that building. Hopefully it will be in Red, White and Blue colors by the end of September.
    Tristan Smith
    1991 Nissan ITR 300zx #56

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