Re: Quattro Vs non-Quattro MPGs

[glen.powell@smc.com]

  The Quattro models should get just about the same MPG as non-Quattro
  models,
  *all else being equal*. Testing has shown that the rolling resistance of
  a tire is reduced if a specific amount of torque is applied. 2WD applies
  too much torque and un-driven wheels apply too little torque to minimize
  MPG. With Quattro drive the torque is 1/2 that of the driven wheels on a
  2WD car and obviously greater than that of undriven wheels. The torque
  applied when all wheels are driven approximates the optimal torque to
  minimize MPG. This effect pretty well negates the extra losses due to the
  Quattro drive's weight and parasitic losses from seals and bearings, so
  Quattro drive in and of itself does not increase fuel consumption. Now,
  of course, *all else is not equal*. Audis with Quattro drive typically
  have much lower final drive ratios and require more revs/mile and hence
  more fool per mile. Final drive ratio is a very significant factor in
  MPG, one of the most significant. Also, Quattro models typically have a
  higher level of equipment, suspension and hence weight. So, between the
  lower final drive ratios and additional equipment and weight you will
  typically see lower mileage in Quattro Vs non-Quattro, but it's *NOT* due
  to the Quattro drive.

  -glen