[s-cars] Spring Measurements: Eibach/Stock/Audi Euro Sport

[Mark Strangways]

Very nice...
But I thought the Eibachs are a progressive rate spring.
Mine sure look that way.
Mark S

  ----- Original Message ----- 
  From: Voits 
  To: s-car-list at audifans.com 
  Sent: Monday, July 26, 2004 11:49 PM
  Subject: [s-cars] Spring Measurements: Eibach/Stock/Audi Euro Sport


  S-Heads:
  I have benchmarked spring rates for decision purposes, and list the results
  below.  The reason I did this is because the data I've seen online/from
  vendors/word of mouth/urs4.com  did not add up to a coherent picture.  I
  wanted better data.

  Measurements were taken using the QA lab at Curran Coil Spring, Wilsonville
  OR, in May.  Curran manufactures coil springs for OEM applications and they
  do spot testing on their product using this facility.

  The setup allowed for precise measurement (+/- .005" est.) of spring length
  with simultaneous force readout (guessing +/- 5lbs est.)on an automated
  press set-up designed exactly for this purpose. Our process was to begin
  taking measurements at approx 500 lb load, and then to plot two or three
  data points up to about 1100 lbs.

  The contestants:
  (A) Stock springs from my 1995.5 S6
  (B) Audi sport springs (euro OEM option) purchased from Alex Van Gerbig at
  Europrice (802)324-8407
  (C) Eibach springs (purchased from shox.com)
  Front: the correct sedan spring 1527.001VA
  Rear: the avant spring 1517.002HA  This is the culprit in so many 'wrong'
  shipments because orders for the correct sedan 1529.140 box were mistakenly
  fulfilled with the 1529.140E box, the latter from a parallel european part
  numbering system intended for the avant and filled with the 1517.002HA
  spring instead of the correct 1516.002HA part.  I went ahead and tested the
  avant spring for 2 reasons: a) its what I had on hand, b) I'm told the only
  difference b/w the sedan and avant spring is 1 full inactive coil length.  I
  decided to emphasize results from the fronts in any conclusion.

  FRONT:

  Stock Front (labeled silver, silver, yellow)
  Rate: 167 lb/in
  Comments: linear in nature

  Audi Sport Front Spring (silver, pink, pink)
  Rate: 194 lb/in  (+16% over stock)
  Comments: linear in nature

  Eibach Front (labeled 1527001VA, part of 1529.140 <note: not 1529.140E> kit)
  Rate: 200 lb/in (+20% over stock)
  Comments: linear in nature

  REAR:

  Stock Rear (labeled pink, green)
  Rate: 220 lb/in
  Comments: linear in nature

  Audi Sport Rear (labeled blu, blu, blu, yellow, also p/n 4A5.411.115 AG)
  Rate: 232 lb/in (+ 5% over stock)
  Comments: linear in nature

  Eibach Rear (labeled 1517002HA **see note above** part of 1529.140E kit)
  Rate: 249 lb/in (+13% over stock)
  Comments: linear once the car's load collapses the initial inactive coils


  SPRING RATE CONCLUSIONS:
  Even though the test arrangement was precise in nature I chose to focus on
  bench mark type results.  The spring constant of the Audi Sport and Eibach
  springs are similar to one another.  My conclusion is that one should select
  one over the other from a ride height point of view.

  RIDE HEIGHT CONCLUSIONS:
  Since the spring rates are neraly the same, you should choose springs based
  on the ride height.  Eibachs deliver 1.5" drop and the Audi Sport Springs
  are advertised to provide 2 cm drop, or less than an inch.

  EIBACH RIDE HEIGHT OBSERVED:
  I installed the correct Eibach 1529.140 kit (1527.001VA Front, 1516.002HA
  Rear) and I have *exactly* 1.5 drop in both the front and the rear.  Despite
  this exact drop the rear looks a touch low to my eye > so I thought I needed
  to install the 1529.Perch assembly ("spacers") from Eibach which I own, and
  would raise about 3/8 inch.  Before proceeding I placed a bottle jack under
  the center rear body and raised the rear by this amount.  Too high!  I
  decided that the aesthetics are such that one might want to raise the rear
  by 1/8", but the Eibach did lower the car evenly front to rear and that the
  spacer is too much to add.

  ON THE ROAD EXPERIENCE:
  I initially panicked when I installed the Eibach Bilstein setup as it was a
  dramatic change. But after a few weeks have learned I love the trade-offs.
  It remains a bit harsh at low speed on potholes, etc.  but works very well
  at speed and has given the car an altogether safer, more precise &
  commanding feel.  Even the stock brakes feel more sensitive because their
  function is not lost to body squat.  I installed the 2Bennett camber plates
  and aligned to factory specs and tramlining has disappeared.

  I'm convinced the Audi Sport springs would deliver the same experience
  described here, but with more ground clearance. (contact me if you want to
  buy my extra set)

  Steve Voit
  voits at comcast.net
  95.5 S6
  Seattle




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