87 vs. 89 vs. 91 Octain fuel. My findings....

That's some good info, chris!

Thanks for doing the legwork!

 

but how much more did you pay per gallon of 91? the mpg may not make up for the initial investment in $ per miles lol

 

Well for the 155 mile trip assuming a difference of 20 cents per gallon between 87 and 91, you'd save about $2. I personally have never noticed a difference in my cars. Shouldn't make too much of a difference, only difference is a higher flash point on the 91.

 

X2

What's the cost factor broken down into your findings?

 

Do you have 93 stuff over there in AZ?

I think the gas here in Texas is 87 91 93.

I use the 91 stuff ever since I noticed a better performance from 87.

 

what about pure racing fuel. could that be good or bad. i know that there could be a possibilty of burning the o2 sensors out and all but still...

 

I run premium. I can feel a difference in how my truck drives, and I usually get 1MPG more than I do with regular. For me, its worth the extra cost.

 

You guys KNOW how I feel on this=thats why I say 91 ALL THE WAY Screw that 87 crap!

 

Now, that's only for engines that can make something out of 91.

If you put 91 in an engine that recommends 87, I doubt you'd get anything extra out of it.

 

R ight you are

 

How'd you figure $2.00?

What's all that break out to be in cost per mile for both?

 

Let's say Plus is about 15 cents more than Regular. It's more like 10-12 cents more here in Texas, but lets use 15 cents for the nationwide average.

A fill up of 20 gallons would be 20gal * $0.15 = $3.00 more if you use Plus, or also $3.00 saved if you use Regular over Plus.

Let's say that using Plus gets you 1.5mpg more than regular. Could be as low as 1, could be higher.

So, 1.5mpg * 20gal = 30 miles more per tank. Most of us get ~18mpg, mixed driving (don't kid yourself with lifted with heavy off road tires).

So 30mi/18mpg = 1.667 gallons worth of "extra" gas if we had used plus. Well, currently gas averages $3.65 (Reg) nationally, so 3.65 * 1.667 = $6.09 more than would have to been spent using Regular to travel as far as when using Plus. So, $6.09 - $3.00 saved earlier when using Regular = $3.09 saved when using Plus.

 

That's terrible MPG!! 80-90 mph up hills.. must be those AZ money trees?

 

I looked at it a different way....
Using Chris's original figures of 20cents more (per say) for 91 versus 87.

87 Costs $4 a gallon (for example) He's getting 15.5mpg. That's $.2581 cents per mile.
91 Costs $4.20 a gallon. He's getting 16.6mpg. That's $.2530 cents per mile.

We'll say you're getting 350 miles per tank - which leaves you with a total cost of:
$90.335 for 87 for 350 miles
$88.55 for 91 for 350 miles
That's only $1.79 savings for 350 miles.

If you drop the gas price to $3.50 & $3.65 - then the difference is only $2.06 per 350 miles.

The cost per mile will probably vary a lot between one truck to the other and how we drive etc. You'd probably have to run your own tests to see how your own results end up.

 

91 octane (that is 100% pure gas here in WI) that has the +1 mpg advantage over 87 10% ethenol and with the added benefit of cleaner engine if your keeping the truck well into its later years could be argued as the way to go indeed!

After my intake install this week, I will try to get some results with 87 - 90 % gas vs. 91 - 100% gas