IndyCar engines represent remarkable feats of engineering and experience. These 2.2 liter (135.25 cu in) turbocharged V6 engines weighing a mere 114 kg (250 lbs) might be an appropriate size for pushing along a mid-sized sedan, but pump out about 650 horsepower at up to 12,000 rpm. A combination of direct and indirect fuel injection allows these tiny engines to swallow the enormous amount of fuel needed to achieve such power.
Normal turbo boost is 21.75 psi for these mini-brutes, with a passing option allowing a temporary (15 to 20 seconds, depending on the track) increase to 23.2 psi. Ten such boosts are allowed during a race, after which the capability is self-terminated. It isn't yet clear how much advantage the extra boost will deliver to these E85 powered thoroughbreds, but time will tell.