Project is officially started
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Weight of those 15" wheels 5.8 kg per piece.
Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com
Rough calculations of the project first with only diesel powertrain.
On lupo 3l you can reach 3 liters at 100 km/h speed with 1.2 TDI.
Lupo weights 950 kg with driver and A8 target weight 1500 kg = 36,7% difference in weight every 10% increase is 2-4% on highway --> max 14,7% higher fuel consumption
Lupo 3l CdA 0,29*2,0=0,58 Audi A8 modded 0,23*2,2=0,506 = A8 is 12,7% better so 12,7% less fuel consumption on highway speeds
That means I should try to keep the gear ratios pretty close to same as in my Lupo 3l gearbox. That is one reason behind that I will first test 195/65R15 tires. Other is weight savings and ofcourse the frontal area gets smaller.