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Old 03-22-2015, 05:30 PM   #52 (permalink)
Vekke
Mechanical engineer
 
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Join Date: Jan 2009
Location: Kitee (Finland)
Posts: 1,272

Siitin - '98 Seat Cordoba Vario
90 day: 58.56 mpg (US)

VW Lupo 3L --> 2L - '00 VolksWagen Lupo 3L
Diesel
90 day: 104.94 mpg (US)

A8 luxury fuel sipper - '97 Audi A8 1.2 TDI 6 speed manual
90 day: 64.64 mpg (US)

Audi A4B6 Avant Niistäjä - '02 Audi A4b6 1.9tdi 96kW 3L
90 day: 54.57 mpg (US)

Tourekki - '04 VW Touareg 2.5TDI R5 6 speed manual
90 day: 32.98 mpg (US)

A2 1.4TDI - '03 Audi A2 1.4 TDI
90 day: 45.68 mpg (US)

A2 1.4 LPG - '02 Audi A2 1.4 (75hp)
90 day: 24.67 mpg (US)
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http://www.caranddriver.com/features...d-tires-tested
I did some number crunching:
Estimation of the VW Golf 2.5 automatic weigth: 3000 lbs
Biggest weigth difference in the test was 54 lbs vs 40 lbs -> 14 lbs x4=56 lbs of standing weigth. Because its rotating weigth you can try using x3 to get actual effect to acceleration. --> 168 lbs lighter car
168/3000=0,056 ->5.6% ligther car

0-60 MPH acceleration: (7,6sx0,056)+7,6s ->8,02seconds slower time with heaviest wheel. measured time was 7,9s for that 19" wheel set

1/4 mile: (15,9s*0,056)+15,9s -->16,8s. Actual time was 16.1s so calculation is not accurate here for some reason. Check that last link. In 1st and 2 gears the wheel weigth effect can be up to 30% higher than with higher gear as low as 5% with same weight difference.

Then again 0-100 mph: (22,3s*0,056)+22,3->23,5s measured time was 23,4s. I think here the aero starts to slow down as effect was not that big at that 1/4 mile times even speeds were already 86-88 MPH.

Here is nice calculator: http://stephenmason.com/cars/rotatio...ml#wheelstires
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Last edited by Vekke; 03-22-2015 at 06:08 PM..
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