Fasterproms Flex fuel kits allow for newer GM performance engines to run on straight gas, straight ethanol, or any blend of e85 and straight gasoline. The most popular combinations are E85 (85% ethanol and 15% gasoline) or your everyday gas (10% ethanol and 90% gasoline). Please remember that our E85 Conversion Kit works in conjunction with your car's computer and together will automatically sense the gas to ethanol ratio and make all of the adjustments necessary for a seamless FlexFuel experience. Users can experience gains as high as 65RWHP on E85 in forced induction applications. We have also observed over 40RWHP on direct injection naturally aspirated applications. Tuning required for proper functionality.