crazy_horse3030

Anyone find that switching from 87 octane to a higher octane gives them higher gas milelage. Right now I get 18 mph out of a 2.7 3rz-fe. I heard going to 89 octane or 93 might give me a couple more miles per gallon. Any insight?

thanks

Elkaholic

hasnt helped me yet, thinking Im going back to 87. However I havent done hardcore number tests.

mastacox

It's hard to say, but nothing wrong with a few tanks to see. I would suspect the mpg would do down a little bit because the specific energy content of higher octane gas is lower than lower octane gas (wierd, huh). Then again, depending on the engine, it's possible some engines (especially ones designed to run on higher octane gas, such as forced induction or high-compression) will tend to run a little more efficiently with higher octane gas, yielding a higher MPG rating.

MARSHALLMAY

I just tried a tank of 89 up from 87. Idles smoother. I won't know the mileage change until I fill up, maybe tomorrow or Saturday.

ARB1977

Using a higher octane thats not required doesnt do anything for your engine other than burn hole in your wallet and also creates more carbon becasue of the unburnt fuel.

mastacox

This first part is true...

...the second part, not so much. An engine will not run leaner/richer based on a specific octane gas. That's what an oxygen sensor is for.

Funrunner

I found this to be true. My truck also runs better with the higher octane. It's kind of a trade-off... our gas prices are extremely high here. I try to throw the good stuff in alternating every few tanks.

ARB1977

I run this stuff called FP60 every fill up. Use 1oz for every 5 gallons of fuel. It lubercates the entire full system. It comes in a gallon jug and you can get a 16oz measuring bottle as well.

YUonDAGround

I get 23 mpg using 89octane where I used to get 19 with 87 octane. I actually got 370 miles on my last tank of gas. ALSO I noticed that my valves dont ping whenever I use 89 octane, which was the real reason I went up to 89.

Bruce

crazy_horse3030

edit. I meant MPG. Lol. I put mph. Surprised nobody roasted me on it yet

crazy_horse3030

Can a lack of backpressure cause a poor MPG? I got a Header and a magnaflow flow through muffler. could that allow it to breath TOO WELL?

Thanks

mastacox

Low backpressure can cause a loss of low-end torque, which might in turn cause you to use the accelerator more to get up to speed and use more gas in the process.