Tesla still doing poorly on J D Powers survey

[Calliope]

For example, they publish the roll down coefficents. These generate the power curve for all speeds.

Could you tell me more about that?

 

[bwilson4web]

Could you tell me more about that?

Google "EPA Test Car Database" and you'll find a link to: https://www.epa.gov/compliance-and-fuel-economy-data/data-cars-used-testing-fuel-economy

Download the version you want and load it into a spreadsheet. The coefficients are in the right-most columns:

• Target Coef A (lbf)
• Target Coef B (lbf/mph)
• Target Coef C (lbf/mph**2)

The HP power formula is:

• $E2*(B$2 + (B$3*$E2) + B$4*($E2*$E2))/375
  • $E2 - velocity in mph
  • B$2 - Coef A
  • B$3 - Coef B
  • B$4 - Coef C
  • 375 - constant

So I was able to make this chart:


The EPA has well documented test procedures which makes comparing different vehicles easy.

Bob Wilson