To answer Adam's question and look at the "why" of a 6 speed auto lets work some numbers:
The various first gear thru top gear ratios are:
4L65E (A4)= {3.06,1.63,1.00,0.70} (4 speed auto)
6L80E (A6)= {4.027,2.364,1.532,1.152,0.852,0.667}(6 speed auto)
T56 (M6) = {2.66,1.78,1.30,1.00,0.74,0.50} (6 speed manual)
Some quick calculations give the following torque multiplication factors for axle ratios times tranny gear ratios. These use the Corvette axle ratios with the known Caddy A6.
2.56*x6L80E = <10.31, 6.05, 3.92, 2.95, 2.18, 1.71> (*expected axle with A6)
2.73*x4L65E = < 8.35, 4.45, 2.73, 1.91> (*current std A4 axle)
3.15*x4L65E = < 9.64, 5.13, 3.15, 2.21> (*current hi perf A4 axle)
3.42*xT56 = < 9.10, 6.09, 4.45, 3.42, 2.53, 1.71> (*current M6 axle)
Comment 1: The last number in each series is the top effective axle ratio. The 1.71 ratio of the 6 speed manual is matched by the 6 speed auto! Yes Adam that should give a better highway EPA rating.
Comment 2: The 10.31 first gear of the A6 might require a very large tire budget.
Comment 3: The A6 appears to give the best of both worlds. These data were first assembled by RK on another board.
|UPDATED|4/8/2005 9:22:27 AM (AZT)|/UPDATED|
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Curt Franz LeMans Blue Coupe born on Sept 15th, 2005