YouTuber LegitStreetCars has done the seemingly impossible by getting 40mpg in a 400hp Corvette C5. The challenge was to take a Corvette and max its fuel millage without robbing the car of its inherent Corvetteness. The test took a 1999 C5 Corvette, dubbed the "Ecovette", from Chicago to Madison, Wisconsin and back to the same gas station to refuel and test the results.

3 Prep Work

via motor1.com

To prepare for the hypermiling run LegitStreetCars did a lot of the usual work on the car. It had nearly 140,000 miles on the odometer, so a full tune up was in order. He replaced all the fluids, plugs, and some wires to freshen up the engine. Next was filling the tires up to max pressure and lowering the car for a lower drag c0effecient.

2 Better Living Through Chemistry

via motor1.com

The biggest change done to the 5.7l V8 was in the fuel mixture. The keystone tune actually added 16 hp to the car but more importantly adjusted the air fuel ratio (AFR) at lower revs. The goal was to achieve the stoichiometric ratio, the exact amount of fuel needed to burn all the oxygen present. At low RPMs the cars AFR went from a standard 14.5:1 to 17:1.

1 314.6 Mile Round Trip

via motor1.com

After getting baselines using the Corvette for his general commute, the hypermiling test was done via a round trip from Chicago to Madison and back again. In winter driving before the tune he was managing 20mpg in mixed use, with the tune he was able to add another 5-6mpgs. With the addition of a wide band O2 sensor to monitor when the car was in lean burn mode. The final result was an average of 40.2 mpg from a 20 year old 400 hp V8 Corvette. Not bad at all!

via LegitStreetCars