Does higher octane improve mileage?

[Jeff Cozadd]

I recently bought a new impala ls. It's recommended octane is 87. I have been running 93 in it. I assumed the higher the octane, the better the gas. I get around 22-23 mpg for an in-town/city average. I was hoping for a little better mileage. Would I get better mileage running the recommended 87? Anyone else with the impala ls I would be interested in what mileage your car gets and what octane fuel you use. Thanks

 

[Carl Meyer]

I don't have an Impala, but typically on most cars the increased octane does not necessarily improve performance unless the car is programmed to use premium fuel.

 

[Larry Harp]

Use what is recommended by the manufacturer. If it makes you feel better to spend the extra money on your new darlin' go ahead and put the 87 octane in and send me the differance. I promise I will put it to good use.



Seriously, run a tank of both and do the math. If your engine isn't pinging the lower octane should be your choice.



Harpo

 

[Wendell Little]

Normaly there is no added benifit to using higher octane fuel than that which it needs/labeled for. If it's rated at 87 and does not ping, you are wasting your money. If it pings only when at HIGH temp and under a LOAD, use higher octane for those circumstances. Carbon build-up could also increase octane requirements. Wendell

 

[TOMMY RICH]

There is added benefit usually only in higher HP engines that require higher octane to keep the valves from pinging. I burn 92 or 93 in my Silverado if I can get it cheap enough...and keep in mind if you mix 87 with it you'll still have 89 or better. It does improve gas mileage on larger engines but, for everyday situations and the prices the way they are....87 is fine for just about anything.

 

[Andrew Zuber]

We're getting the same mileage as you with 87 Jeff...

How do you like that Impala???



It's a revolution!!!



az

 

[Larry Harp]

I think JR is buying one just like that.



Harpo

 

[Jeff Cozadd]

Andy, I like mine alot. It's victory red, leather, sunroof, xm radio. I am very happy with it so far, only 1,000 miles yet. It was a new 03 so I got a great deal.

 

[Corey Carrico2]

Use what the manual suggests...higher octane gas is less "explosive" than lower octane gas and could actually decrease your horsepower/efficiancy. A lot of the engine management software on todays cars will adjust for the octane being run but you are usually just wasting $$$. Now NEVER go lower than your engine requires...mix a high compression engine with more explosive lower octane gas and push the engine and you could have big problems.

 

[Rich Stern]

You have to test it yourself. Run several tanks of both and measure your mileage carefully, hopefully in the same driving conditions.



Some cars' ECU computer will advance the timing of the engine with higher octane fuel because the high octane prevents predetonation (early combustion of the fuel/air mix before the spark plug fires). The engine will advance the timing to the point where there is slight detonation, and then retard the timing just slightly below that point.



When the timing is advanced (to a certain point), more power is generated on the same amount of fuel, which means more efficiency.



Generally, the gain in mileage is not enough to justify the extra cost in premium fuel. But if your car runs betters, you may be able to justify it.

 

[Bill McElroy]

I had a 2002 Impala and it gave me the best all around mileage with mid-grade. I use that in my Blazer's too...

I don't notice much difference using premium, so i can't justify the addt'l cost.....but I notice a BIG difference when I use Mid-grade(89) over Regular(87). So,..I use 89 all the time, unless my wife puts gas in for me,...then it's going to be 87!!..LOL...She goes for price over performance!!..LOL Stick with 89....you'll be happy with that. BTW,..those Impala's are awesome cars...loved ours!



Mac

 

[Michael Snow]

I've seen several stories about the "premium myth". Quiktrip has or had a pamphlet about it. It said without question that premium will not get you better gas mileage in a vehicle that doesn't call for it.



However, I had an 87 mustang (4cyl) that I SWEAR to you ran better and took more time between fill ups when it ran Amoco 93 octane vs 87. This was back when Amoco was still Amoco and they were running the "promotion" where the premium had a glass in the fuel handle with a few rubber balls in there to show you how "clear" and "clean" their premium fuel was.



With the difference around 20 cents between reg and prem gallons, I would run 87 now .