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1986 Volvo 244 DL, Everything is dying.

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RickHaleParker
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Re: 1986 Volvo 244 DL, Everything is dying.

Post by RickHaleParker » Sat Dec 14, 2019 12:22 am

volvolugnut wrote:
Fri Dec 13, 2019 8:27 am
Then the drag increase is square of 120 MPH and 100 MPH. 14,400 divided by 10,000 is 1.44 or 44% increase in drag.
I'm not sure that the rate of energy loss is proportional to drag but it is a reasonable assumption. All the other factors should be constants. Substitute 1 for the constants then the ratio of 120²/100² = 1.44.

The energy lost due to drag = Fdrag⋅displacement. To check your assumption, you would need to calculate the drag for each speed, know the displacement, calculate the energy lost each speed, then get the ratio.

I do think you are on the correct path. Another equation states: The power needed to push an object through a fluid increases as the cube of the velocity. Image


What surprised me is Drag and Kinetic energy increased at the same rate. Kinetic energy would increase 44% if there was no drag. Then again it is expected if all the other variables can be substituted with 1.

Kinetic energy = 1/2 * Mass * Velocity² .
Ke 100 = 1/2 * M * 100²
Ke 120 = 1/2 * M * 120²

(0.5 * M * 100²) / (0.5 * M * 120²) =
(0.5/0.5) * (M/M) * (100²/120²) =
1 * 1 * 100²/120² =
100²/120²

Same ratio you got in the drag equation.
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Platform: P80 1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.
Platform: X40 (Nedcar) 2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.
Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
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93Regina
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Re: 1986 Volvo 244 DL, Everything is dying.

Post by 93Regina » Sat Dec 14, 2019 6:40 am

Automobile drag coefficient
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Capture.JPG
Capture.JPG (25.11 KiB) Viewed 5 times

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Re: 1986 Volvo 244 DL, Everything is dying.

Post by RickHaleParker » Sat Dec 14, 2019 6:49 am

Per the equation directly above, almost 75% more power to go from 100 MPH to 120 MPH

(120/100)³ = 1.728
--------
Platform: P80 1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.
Platform: X40 (Nedcar) 2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.
Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
Platform P2 2004 S60R, B2524T4, AW50/51 AWD, Bosch Motronic 7.0, BorgWarner K24 turbocharger, Plant Ghent Belgium.

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