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Old 05-29-2015, 07:14 PM   #13 (permalink)
BabyDiesel
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Join Date: Dec 2012
Location: Johnston County, NC
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Quote:
Originally Posted by NeilBlanchard View Post
I did a coastdown test on my Scion, and my method of data collection worked well, I think: I video recorded the SG II set to KPH. I paused the video at the instant the car reached the 70KPH, noted the time, moved 10s forward, and noted the speed.

There is no bias.

The challenge with this is to "know" the Crr in order to get the estimate for the Cd.
No bias with my brother. He kept an eye on my speed and did the timing. I have no way of knowing the coefficient of drag of my tires. I have searched Google and nothing turned up The are Chinese made, regular car tires, so I knew the Crr would be between 0.01 & 0.015 from researching typical Crr's Mine came out on the low side.
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Past threads:
ZX2 modding thread
Ecomodder's Top 10: How they do it!
ZX2 Aerodynamics: Shooting for 0.15 Cd
ZX2 coast-down testing for Cd & Crr
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