14mpg on 94 octane?

So I finally bit the bullet, reset the trip odometer and calculated my gas usage. 259 miserable miles on a tank of 94 octane. WTF!? Strictly use 94. Clean throttle body, afe dry filter, magnaflow exhaust, somewhat heavy foot

 

Did you only do it once? Try doing it a few times, each time filling the tank the same way, right to the top.

 

I'm on my second time right now at under a 1/4 tank and it looks like it's going to be the same

 

Tires larger?

 

265/70/17 bf Goodrich ko2

 

Any difference in driving experience from using 94 rather than 87/89? Maybe it's just a Canadian thing ya?

 

I got 25.6 mpg out of my tank yesterday with 91 octane 100% gas...

If you want more mileage, the way you are driving isn't working.

 

Imperial gallons and 14 mpg? You're leadfoot is heavier then you think or you have something else going on.That's like 11 mpg in US gallons.

You don't need 94 octane anyways, it's a waste of money.

 

Having similar issue for mine too... Tried babying it on gas and all, still only got my best up to about 15.8mpg. Been tracking it about two months too. I have the bigger tires too (Nitto Trail Grapplers 265/75/16), plus a rear plate bumper, so there is a little extra weight, but it shouldn't be THAT noticeable, should it? Up until about maybe 3 months ago I feel like I was doing fine, then it suddenly dropped. And I've clocked it at upwards of 21mpg highway just last summer on a trip we took, so it's pretty obvious to me.

Next step is pulling the spark plugs and checking them, but I'm only up to 33k miles so they shouldn't be that bad yet I hope.

 

I dive like NASCAR and I get 18-19 MPG....

 

Taller tires will register less miles on your odometer so perceived lower mpg.

 

That's the thing... I was getting that 21+ mpg WITH these tires when they were brand new. Have almost 25k miles on them now.

 

Yeah I wanted to calculate based on my real driving habits. I also Nascar around. It's actually 405km from a full tank. 94 makes a huge difference, I definitely feel it

 

Have you tried 100% gas or at least premium for a couple of tanks?

 

I quit taking off at a stop light like i was staged up against John Force in a drag race and my mileage improved. (22.5 MPG)

 

89 chevron octane. 22 mpg.

 

Octane is the more stable hydrocarbon portion of the gasoline fuel mixture. Higher octane means your engine can abuse it more before it spontaneously detonates. Engines that run hot or use higher compression ratios need higher octane to prevent early detonation/engine knocking.

Lower octane is less stable and easier to ignite/detonate. If you have a low octane engine it is built to take advantage of this instability and you will loose fuel economy by running a higher octane or more stable fuel.

http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/question90.htm

 

Also, your calculations are going to be off if you are judging miles per tank. You need to calculate miles driven since the last fuel up by the amount of actual gallons used to fuel up. Do that three times in a row for an average. Better yet, track your fuel-ups using www.fuelly.com.

 

Thanks very informative.
Question: what's the compression ratio on my engine? The article states that the octane level to be used is dependant on the compression ratio of the engine.

I'll try this. I have to fill up today

 

Once I'm through this tank I'll try the higher octane. Been using regular 87 since I got the truck with no problems until now.

Also, I already use the Fuelly app for tracking. Even before that, though, I knew about using actual miles driven since last fill up to calculate the mpg, it's how I've always tracked it in the past.