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    Results 1 to 6 of 6
    1. #1
      Join Date
      Jan 2004
      Location
      NW Suburbs, Chicago
      Posts
      560

      Auto X last weekend

      So I was at an Auto X this past weekend and am looking over my G-tech readouts and lookin over my videos a little. My G-tech shows me pulling .9G lateral and .05 longitudinal. So does that mean I pulled .95Gs total or is the total number different or does it even matter?

      The reason I ask is I was running on my Penske Kmart junk tires that were sitting in my garage for 6 years and I was just surprised that they held up that well and that I turned the times I did with them.



    2. #2
      Join Date
      Jul 2005
      Location
      Mountain View, CA
      Posts
      9,583
      Country Flag: United States
      The .5 longitudinal is recorded under acceleration or braking and the .9 lateral during cornering. Two different axis of motion.

      The .9 was likely a transient spike. Different from a skid-pad measurement which is a measure of sustained cornering load.
      True T.

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    3. #3
      Join Date
      Jan 2004
      Location
      NW Suburbs, Chicago
      Posts
      560
      Ok so the sustained cornering Gs are different from what I experienced in Auto X? Correct me if im wrong but also with using the G-tech if I reach a high enough spike in the lateral Gs the car will obviously spin out. With that when it does actually go into a spin that should show me what the peak is that the tires I have can hold at? or does it vary a lot depending on other factors?

    4. #4
      Join Date
      Nov 2002
      Location
      state of confusion
      Posts
      1,499
      Country Flag: United States
      Your resultant acceleration at any given instant is the vector sum of the longitudinal and lateral acceleration terms, and is not necessarily in either direction (and generally isn't).

      [Resultant Acceleration] = SQRT ( [LAT ACCEL]^2 + [LONG ACCEL]^2 )

      If you actually did see 0.9g lateral and 0.5g longitudinal at precisely the same instant, the car was seeing a resultant acceleration of just under 1.03g in a direction about 29* off the purely lateral.

      Norm
      '08 GT coupe, 5M, suspension unstockish (the occasional track toy)
      '19 WRX, Turbo-H4/6M (the family sedan . . . seriously)
      Gone but not forgotten dep't:
      '01 Maxima 20AE 5M, '10 LGT 6M, '95 626, V6/5M; '79 Malibu, V8/4M-5M; '87 Maxima, V6/5M; '72 Pinto, I4/4M; '64 Dodge V8/3A

    5. #5
      Join Date
      Nov 2005
      Location
      Beacon Falls, Connecticut
      Posts
      239
      .901g at 32.5 degrees. it was .05g not .5, unless it was a typo in the original post right?

    6. #6
      Join Date
      Nov 2002
      Location
      state of confusion
      Posts
      1,499
      Country Flag: United States
      Make that 0.901g at 3.2* and I think we'll finally all be on the same page.

      (I must have not looked far enough up the topic before - 1.03g is rather optomistic performance for the tires as described . . .)

      Norm
      '08 GT coupe, 5M, suspension unstockish (the occasional track toy)
      '19 WRX, Turbo-H4/6M (the family sedan . . . seriously)
      Gone but not forgotten dep't:
      '01 Maxima 20AE 5M, '10 LGT 6M, '95 626, V6/5M; '79 Malibu, V8/4M-5M; '87 Maxima, V6/5M; '72 Pinto, I4/4M; '64 Dodge V8/3A





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