FUEL TYPE · E85 / FLEX FUEL
E85 tuning
E85 (85% ethanol, 15% petrol) is a 105 RON-equivalent fuel widely available in the US and parts of Europe. The high octane lets tuners run more ignition timing and higher boost without knock — yielding +20-50% more power on the same petrol turbo platform compared with 95 RON pump fuel. The cost: ethanol's lower energy density means BSFC rises 30-40%, so fuel system sizing matters.
Why e85 tuning responds the way it does
E85 enables aggressive ignition timing + boost increases that pump fuel cannot support. Common gains: petrol turbo on E85 = 1.5× the power output of the same platform on 95 RON.
Services applied on e85 tuning
E85 tuning requires recalibrated fuel maps (BSFC up ~30%), wider injectors (use our injector duty calculator), and a wideband O2 sensor for real-world verification. E85 cannot be flex-blended without flex-fuel sensor support in the ECU.
Engines in this category
Popular engines covered by e85 tuning workflow: