What do you think the mpg would be on a car with engine that is 100% efficient (I know it's impossible but hypothetically)? - Quora
![FOTW #1237, May 9, 2022: Fuel Economy for All Vehicle Classes Has Improved Substantially Over the Past Two Decades | Department of Energy FOTW #1237, May 9, 2022: Fuel Economy for All Vehicle Classes Has Improved Substantially Over the Past Two Decades | Department of Energy](https://www.energy.gov/sites/default/files/2022-05/FOTW_1237.png)
FOTW #1237, May 9, 2022: Fuel Economy for All Vehicle Classes Has Improved Substantially Over the Past Two Decades | Department of Energy
![FIGURE 8-6 Car and Truck Corporate Average Fuel Economy (CAFE) and Miles per Gallon (MPG): Model Years 1975-2013 | Bureau of Transportation Statistics FIGURE 8-6 Car and Truck Corporate Average Fuel Economy (CAFE) and Miles per Gallon (MPG): Model Years 1975-2013 | Bureau of Transportation Statistics](https://www.bts.gov/sites/bts.dot.gov/files/legacy/8_6_new.gif)
FIGURE 8-6 Car and Truck Corporate Average Fuel Economy (CAFE) and Miles per Gallon (MPG): Model Years 1975-2013 | Bureau of Transportation Statistics
![Fuel economy and average vehicle cost vary significantly across vehicle types - U.S. Energy Information Administration (EIA) Fuel economy and average vehicle cost vary significantly across vehicle types - U.S. Energy Information Administration (EIA)](https://www.eia.gov/todayinenergy/images/2014.07.22/main.png)
Fuel economy and average vehicle cost vary significantly across vehicle types - U.S. Energy Information Administration (EIA)
![New U.S. Vehicles Are More Fuel Efficient Than Ever Before, But Not Enough to Offset High Gas Prices | TIME.com New U.S. Vehicles Are More Fuel Efficient Than Ever Before, But Not Enough to Offset High Gas Prices | TIME.com](http://www.umich.edu/~umtriswt/img/EDI_mpg_February-2012.png)
New U.S. Vehicles Are More Fuel Efficient Than Ever Before, But Not Enough to Offset High Gas Prices | TIME.com
![FOTW# 1177, March 15, 2021: Preliminary Data Show Average Fuel Economy of New Light-Duty Vehicles Reached a Record High of 25.7 MPG in 2020 | Department of Energy FOTW# 1177, March 15, 2021: Preliminary Data Show Average Fuel Economy of New Light-Duty Vehicles Reached a Record High of 25.7 MPG in 2020 | Department of Energy](https://www.energy.gov/sites/default/files/2021/03/f83/fotw1177.png)
FOTW# 1177, March 15, 2021: Preliminary Data Show Average Fuel Economy of New Light-Duty Vehicles Reached a Record High of 25.7 MPG in 2020 | Department of Energy
![FOTW #1237, May 9, 2022: Fuel Economy for All Vehicle Classes Has Improved Substantially Over the Past Two Decades | Department of Energy FOTW #1237, May 9, 2022: Fuel Economy for All Vehicle Classes Has Improved Substantially Over the Past Two Decades | Department of Energy](https://www.energy.gov/sites/default/files/styles/full_article_width/public/2022-05/FOTW_1237.png?itok=bOmGiBgI)