An 8.3 degree Celsius increase in temperature makes a car 7% slower in acceleration from 115km/h to 140km/h
Temperature Effect on Acceleration – How the tests were done
6 back to back full throttle pulls, 3 in one direction, 3 in the other, on the exact same piece of road and within 30 seconds of each other.
6 pulls done at a low temperature (9.3C)
6 pulls done at a high temperature (17.7C)
A pull consisted of a full throttle acceleration in 3rd gear from 115km/h to 140km/h so as to not include any gear changes.
The acceleration times were averaged to give one average acceleration time for the low temperature runs
The temperatures were averaged out to give one average temperature for the high temperature runs.
A further two pulls were carried out at 12C with the predicted acceleration time of 4.05 seconds to 4.1 seconds. The actual average acceleration time of the two 12C pulls was 4.07 seconds. Confirming the accuracy of the low temperature and high temperature results.
Temperature Effect on Acceleration – Results
The car accelerated 0.3 seconds slower due to a temperature increase of 8.3C
Acceleration time from 115km/h to 140km/h was 7% slower at 17.7C compared to 9.3C
Temperature Effect on Acceleration – Conclusion
Temperature plays a surprisingly large effect on acceleration times.
Where acceleration times are quoted for a vehicle, the times should be accompanied by the ambient air temperature. Without knowing the ambient air temperature, acceleration times can be thought of approximate at best.
For large/long acceleration times, for example 10 seconds or more, an 8.3 Celsius difference in temperature could effect the results by 0.7 seconds.
Temperature Effect on Acceleration – Weakness of the Methodology
The difference in barometric pressure was not measured between the two sets of runs.
Thermometer used to measure the temperature of the runs only measured to whole numbers. Using a thermometer which measure to a tenth of a Celsius would yield more accurate results.
Instruments Used For Measurements
Acceleration Times – RaceLogic Performance Box
Temperature – Thermometer built into cars onboard computer. Accuracy of thermometer tested against wunderground.com live temperature reading at same location over 5 days. On board thermometer matches perfectly with wunderground.com figures. Thermometer is consistent and accurate. (Nissan Primera P11)
Low Temp and High Temp Runs
|Temperature C||Accel Time 115-140||Avg Acc Low Temp Runs vs High Temp Runs||Avg Temp Low Temp Runs vs High Temp Runs||Accel Time Difference||Temp Difference|
Addendum Run at 12C