Thread: When to shift
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Old 07-05-2009, 08:25 PM   #5
loosecannon
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Join Date: Jun 2009
Location: canada
Posts: 12
I auto-x my 2004 Boxster (non-S) and was curious about what is the best RPM to launch and shift at. I experimented with launching at 3000, 4000 and 5000 rpm, and with shifting at 6000, 6500 and 7000 rpm. I used a MaxQdata system and did it on a runway we use for auto-x, always starting in the same area, going in the same direction and letting the tires cool between runs. The tires were Bridgestone RE-01R and the only mod to the car is a home made cat back exhaust. I re-tested the different launch RPM at the end of the test to ensure that the conditions were the same. Sorry for not listing the other shift data but I deleted all the data except for the launch at 5000, shift at 7000 rpm ones because that was easily the quickest. Launching at 5000 rpm, shifting at 6000 rpm resulted in 6.1 seconds, shifting at 6500 was 5.7 seconds. Here's the data to 60 mph when shifting at 7000 rpm(before it hits the rev limiter at 7200 rpm) but I have the whole chart to 1/4 mile-note that 0-60 mph is 5.5 seconds:
Time------g--- MPH-- ft
0.000 +0.65 4.04 0.0
0.050 +0.58 5.27 0.4
0.100 +0.54 6.28 0.9
0.150 +0.53 7.06 1.4
0.200 +0.54 7.69 1.9
0.250 +0.55 8.28 2.6
0.300 +0.55 8.86 3.2
0.350 +0.55 9.40 3.9
0.400 +0.57 9.89 4.6
0.450 +0.58 10.37 5.4
0.500 +0.58 10.90 6.2
0.550 +0.58 11.50 7.0
0.600 +0.59 12.14 7.9
0.650 +0.60 12.79 8.9
0.700 +0.62 13.44 9.8
0.750 +0.60 14.47 10.9
0.800 +0.60 15.91 12.1
0.850 +0.63 17.54 13.4
0.900 +0.67 18.79 14.7
0.950 +0.69 19.83 16.2
1.000 +0.69 20.90 17.7
1.050 +0.65 22.09 19.4
1.100 +0.57 23.11 21.0
1.150 +0.51 23.95 22.8
1.200 +0.45 24.69 24.6
1.250 +0.42 25.36 26.5
1.300 +0.43 25.94 28.4
1.350 +0.47 26.45 30.3
1.400 +0.49 26.91 32.3
1.450 +0.49 27.38 34.3
1.500 +0.48 27.87 36.4
1.550 +0.46 28.38 38.4
1.600 +0.45 28.89 40.6
1.650 +0.48 29.38 42.7
1.700 +0.51 29.87 44.9
1.750 +0.54 30.35 47.1
1.800 +0.56 30.82 49.4
1.850 +0.54 31.32 51.7
1.900 +0.52 31.86 54.0
1.950 +0.49 32.52 56.4
2.000 +0.48 33.24 58.9
2.050 +0.46 33.98 61.4
2.100 +0.46 34.62 63.9
2.150 +0.46 35.17 66.5
2.200 +0.47 35.68 69.1
2.250 +0.48 36.18 71.8
2.300 +0.48 36.69 74.4
2.350 +0.48 37.19 77.2
2.400 +0.47 37.68 79.9
2.450 +0.49 38.16 82.7
2.500 +0.50 38.66 85.6
2.550 +0.51 39.11 88.4
2.600 +0.54 39.52 91.3
2.650 +0.53 39.93 94.3
2.700 +0.53 40.40 97.2
2.750 +0.50 40.89 100.2
2.800 +0.47 41.32 103.2
2.850 +0.44 41.71 106.3
2.900 +0.44 42.14 109.4
2.950 +0.44 42.55 112.5
3.000 +0.43 42.90 115.7
3.050 +0.41 43.22 118.9
3.100 +0.39 43.59 122.0
3.150 +0.36 44.02 125.3
3.200 +0.29 44.35 128.5
3.250 +0.23 44.58 131.8
3.300 +0.17 44.76 135.1
3.350 +0.08 44.95 138.4
3.400 +0.10 45.10 141.7
3.450 +0.18 45.16 145.0
3.500 +0.28 45.23 148.3
3.550 +0.42 45.41 151.7
3.600 +0.54 45.75 155.0
3.650 +0.58 46.22 158.4
3.700 +0.58 46.77 161.8
3.750 +0.52 47.35 165.3
3.800 +0.45 47.93 168.8
3.850 +0.38 48.50 172.4
3.900 +0.35 49.03 176.0
3.950 +0.35 49.43 179.6
4.000 +0.36 49.71 183.3
4.050 +0.36 49.93 186.9
4.100 +0.36 50.21 190.6
4.150 +0.38 50.52 194.3
4.200 +0.38 50.83 198.1
4.250 +0.38 51.12 201.8
4.300 +0.37 51.46 205.6
4.350 +0.37 51.82 209.4
4.400 +0.37 52.18 213.2
4.450 +0.37 52.52 217.1
4.500 +0.35 52.88 221.0
4.550 +0.34 53.25 224.9
4.600 +0.34 53.60 228.8
4.650 +0.35 53.93 232.7
4.700 +0.37 54.27 236.7
4.750 +0.38 54.62 240.7
4.800 +0.38 54.96 244.8
4.850 +0.38 55.31 248.9
4.900 +0.38 55.69 252.9
4.950 +0.36 56.08 257.1
5.000 +0.34 56.44 261.2
5.050 +0.34 56.77 265.4
5.100 +0.33 57.12 269.5
5.150 +0.32 57.47 273.8
5.200 +0.33 57.82 278.0
5.250 +0.34 58.15 282.3
5.300 +0.35 58.50 286.5
5.350 +0.38 58.86 290.9
5.400 +0.37 59.23 295.2
5.450 +0.38 59.62 299.6
5.500 +0.38 60.01 304.0

Last edited by loosecannon; 07-06-2009 at 06:47 AM.
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