93 Octane VS. 87 Octane Gas

[freesiagirl]

I can get 93 Octane Gas on Fridays, for the same price as Mid-Grade, which is about .8 cents more than the 87 Octane. So, is it worth it? Does it improve gas mileage? Does it burn cleaner? What's everyone's opinion?

[citydragon]

Originally Posted by freesiagirl

I can get 93 Octane Gas on Fridays, for the same price as Mid-Grade, which is about .8 cents more than the 87 Octane. So, is it worth it? Does it improve gas mileage? Does it burn cleaner? What's everyone's opinion?

Unless you have an octane starved engine like a big block V8, using gasoline higher than 87 octane on a small engine like the Metro is like throwing nickels and dimes out the window. Most cars these days are designed to run on 87 octane and so is the Metro. A well maintained tuned car with proper inflated tires and easy driving will give the best fuel economy.

[91Caprice9c1]

Originally Posted by citydragon

...using gasoline higher than 87 octane on a small engine like the Metro is like throwing nickels and dimes out the window. Most cars these days are designed to run on 87 octane and so is the Metro. A well maintained tuned car with proper inflated tires and easy driving will give the best fuel economy.

I second this. The octane rating of gasolines is directly related to the fuels RESISTANCE to igniting, designed for cars with higher compression/turbo cars/cars running on nitrous etc. Higher octane fuel actually burns cooler, and is harder to ignite. It is best to use the octane that the application is designed for, running a higher octane will only add carbon deposits to the motor.

-MechanicMatt

[idmetro]

To help answer the question about the fuel mileage I experimented with my 86 Sprint running the lowest octane fuel (83 I thnik) versus the highest (93 I think). When the difference between regular and premium (this was in the days before "mid-grade") was .10 per gallon or less I got enough better fuel mileage to pay back the cost of the premium. Once the price spread exceeded .10 per gallon I could not recoup the additional investment. Keep in mind this was on a carbuerated engine. I'd say if curiousity is killing you give it a try, record your results and see how you do, although my bet is with fuel injection you won't see much of a difference.

[Icanfixit]

Originally Posted by 91Caprice9c1

I second this. The octane rating of gasolines is directly related to the fuels RESISTANCE to igniting, designed for cars with higher compression/turbo cars/cars running on nitrous etc. Higher octane fuel actually burns cooler, and is harder to ignite. It is best to use the octane that the application is designed for, running a higher octane will only add carbon deposits to the motor.

-MechanicMatt

Yes I agree with this guy. Your car is designed to run the lower octane gas. And it is true that higher octane fuel burns cooler but like said it is harder to ignite.So in turn your not doing your little car any good by running 93 octane. SO run the cheap gas. 87 octane. And occasionaly run a tank of gas with fuel injector cleaner. Helps keeps the carbon deposits from building up.