can you put 87 in a flex fuel car

[Pete]

Yes, you can safely put standard 87-octane gasoline in a flex-fuel vehicle. Flex-fuel cars, often identified by badges like "Flex-Fuel," "E85," or a yellow gas cap, are engineered with a hardened fuel system to run on a wide range of fuels, from pure gasoline (all grades: 87, 89, 91/93) up to E85, which contains up to 85% ethanol. The vehicle's engine control computer automatically detects the ethanol content and adjusts the ignition timing and fuel injection to ensure optimal performance and protect the engine.

However, while it's safe, it's not always the most efficient choice. E85 typically has a higher octane rating (around 100-105), which allows the engine to produce more power when tuned for it. But ethanol contains less energy than gasoline. You'll experience fewer miles per gallon (MPG) on E85 compared to 87-octane gasoline. The key is to use what's available and convenient; the car is designed for this flexibility.

The following table compares the key differences between the two fuels in a flex-fuel vehicle:

Fuel Type	Typical Ethanol Content	Octane Rating (Approx.)	Impact on MPG	Performance	Best For
87-Octane Gasoline	10% (E10) or less	87	Better fuel economy	Standard power	Daily driving, maximizing range
E85 Flex Fuel	51%-83%	100-105	Reduced fuel economy (15-30% less)	Potential for more horsepower	Performance driving, lower fuel cost per gallon

The main advantage of a flex-fuel car is this choice. If E85 is significantly cheaper per gallon than regular gasoline in your area, the lower MPG might be offset by the lower price, saving you money. Just check your owner's manual for the manufacturer's specific recommendations.

[Cayden]

Absolutely. My truck is a flex-fuel model, and I use 87 all the time. It’s perfectly fine. The whole point of these vehicles is that the computer figures out the fuel mix and adjusts everything on the fly. I only bother looking for E85 if I’m towing something heavy and want that extra kick, or if the price is just too good to pass up. For everyday driving to work and back, regular unleaded works without a single issue.

[AveryLee]

From an engineering standpoint, the vehicle's fuel system components—such as the lines, injectors, and pump—are constructed with alcohol-resistant materials. The engine control unit continuously monitors the air-fuel ratio via an oxygen sensor. When it detects a higher ethanol concentration, it increases the fuel injection pulse width to compensate for ethanol's lower energy density. Using 87-octane gasoline simply means the ECU will maintain a standard calibration. There is no risk of knock or damage.

[McKathryn]

Think of it this way: a flex-fuel car is like a multilingual person. It understands and operates perfectly well in multiple "languages" (fuel blends). Putting in 87-octane is just speaking to it in its most basic, common language. The car handles it effortlessly. You won't gain the potential performance benefit of E85, but you also won't have the fuel economy drop. It's the default, worry-free option for most driving situations.