As you're probably aware, Honda supplies all the engines for the IndyCar series, which is moving from a 90 percent methanol/10 percent ethanol blend to a 100 percent ethanol fuel this year. Honda's been testing the new E100 friendly engines since last year (see related links below). All IndyCar teams will use Honda's V8 HI7R engines again this season, and the engine displacement has been increased to 3500cc (from 3000cc). This increase gives the cars more torque at low-rpm ranges and is necessary because horsepower output with ethanol is lower than with the old methanol/ethanol formula. Auto Racing Daily says the new engines are getting "rave reviews."
ARD asked race team technical leader for Honda Performance Development Roger Griffiths about the new engines, and he said:
"The most important aspect to the fuel change is making sure that all components in the engine that come into contact with the fuel are 'ethanol compatible.' This includes the fuel injectors, fuel lines and seals. The Engine Control Unit [ECU] settings also have been adjusted to meet the "burn" requirements of ethanol. Fuel mileage also has improved, to the point that the 2007 fuel cells have been reduced in size to 22 gallons."