xpensive,
A BTE of 35% is probably somewhat high for an F1 engine. Brake Thermal Efficiency (BTE) is simply the ratio of the energy available at the crank versus the total (LHV) energy content of the fuel.
An F1 engine design has both good and bad points with regards to BTE. An F1 engine design naturally lends itself to good BTE because it is designed to operate mostly at Wide Open Throttle (WOT) conditions, which minimizes pumping losses. And also over a very narrow speed range, which means accessories and intake/exhaust tuning can be optimized for max efficiency rather than driveability. The high CR also helps produce a more efficient combustion cycle.
Unfortunately, an F1 engine is also designed for max power output. Which means that the bore/stroke dimensions are abnormally over-square. A large bore/short stroke engine naturally has high thermal losses, due to greater heat transfer with a large piston crown and combustion chamber surface area exposed to the max temp conditions at combustion TDC. A high RPM engine must also have early EOP valve timing to scavenge properly, which means less total work is extracted from the expansion of combustion gases.
I did a quick calculation, and by my math a modern F1 car uses about 5.3 lbs of fuel per minute at race speeds. At 720BHP and WOT, that would equate to a BSFC of around 0.44 lb/hp-hr, or a BTE of about 29.6% with a fuel having an LHV of 18,400 Btu/lb.
Can someone check my math?
Regards,
Terry