shift chart

Shift Point Calculations and Speed in Gears

The shift point calculations are based on the dynamometer run for my car. The chart shows the torque to the rear wheels as the engine torque is multiplied by the gear ratios and by the final drive gear ratio. The number at the top of the torque in each gear is the ratio of the gear being calculated.

For example, at 2000 rpm, the torque generated at the engine is 96 foot - pounds, and this gets multiplied by first gear's ratio of 3.116 : 1 and the final drive ratio to get 299 foot - pounds of torque at the rear wheels and a speed of 11 mph.

Assumptions include drive tire size of 225 x 45 x 17 and a circumfrence of 78.45 inches, resulting in 807.61 revs per mile. The final drive ratio is 4.529 : 1.

rpm torque 3.116 1st mph 2.05 2nd mph 1.481 3rd mph 1.166 4th mph 0.916 5th mph 0.815 6th mph
2000 96 299 11 197 16 142 22 112 28 88 36 78 40
2500 103 321 13 211 20 153 28 120 35 94 45 84 50
3000 107 333 16 219 24 158 33 125 42 98 54 87 60
3500 110 343 18 226 28 163 39 128 49 101 63 90 70
4000 112 349 21 230 32 166 44 131 56 103 72 91 81
4500 112 349 24 230 36 166 50 131 63 103 81 91 91
5000 107 333 26 219 40 158 55 125 70 98 90 87 101
5500 105 327 29 215 44 156 61 122 77 96 98 86 111
6000 107 333 32 219 48 158 66 125 84 98 107 87 121
6500 114 355 34 234 52 169 72 133 91 104 116 93 131
7000 118 368 37 242 56 175 78 138 98 108 125 96 141
7500 115 358 39 236 60 170 83 134 106 105 134 94 151
8000 108 337 42 221 64 160 89 126 113 99 143 88 161
8500 91 284 45 187 68 135 94 106 120 83 152 74 171
9000 80 249 47 164 72 118 100 93 127 73 161 65 181
dyno chart