MPG 87 vs. 93 Example calculation
Thread Starter
2nd Gear Member
Joined: Apr 2006
Posts: 306
From:
MPG 87 vs. 93 Example calculation
Have a look at this calculation for 87 vs. 93 octane fuel for our 4.0 stangs and see if it seems right to you.
This is based on my typical running cost here in NJ
Example:
87 - $3.00
93 - $3.22
diff = $0.22
Typical fill for me is 13gallons
so, 13 x 0.22 is an additional $2.86
If I were to increase my typical 23mpg to 25mpg by changing fuels I would get 2 extra miles per gallon.
2 x 13 gallons(typical fill) = 26 extra miles
26 miles / 23 current mpg gives 1.13
1.13 x the cost of 87 gas ($3.00) is $3.39
So in this example you spend $2.86 to save $3.39 per tank
Net saving $0.53 per tank + all the benefits of the better fuel
This is based on my typical running cost here in NJ
Example:
87 - $3.00
93 - $3.22
diff = $0.22
Typical fill for me is 13gallons
so, 13 x 0.22 is an additional $2.86
If I were to increase my typical 23mpg to 25mpg by changing fuels I would get 2 extra miles per gallon.
2 x 13 gallons(typical fill) = 26 extra miles
26 miles / 23 current mpg gives 1.13
1.13 x the cost of 87 gas ($3.00) is $3.39
So in this example you spend $2.86 to save $3.39 per tank
Net saving $0.53 per tank + all the benefits of the better fuel
1st Gear Member
Joined: Dec 2005
Posts: 149
From:
RE: MPG 87 vs. 93 Example calculation
...23mpg to 25mpg by changing fuels...
I've always run 89 in mine. I get 28 on the freeway, and an overall average on the 'puter of 22.
I ♥ Acer
Joined: May 2006
Posts: 184
From:
RE: MPG 87 vs. 93 Example calculation
little confusing, but the methodoligy is correct. Would be interesting to plot out based on different mpg's to see if there is a point where you have negative returns.
ORIGINAL: Britinastang
Have a look at this calculation for 87 vs. 93 octane fuel for our 4.0 stangs and see if it seems right to you.
This is based on my typical running cost here in NJ
Example:
87 - $3.00
93 - $3.22
diff = $0.22
Typical fill for me is 13gallons
so, 13 x 0.22 is an additional $2.86
If I were to increase my typical 23mpg to 25mpg by changing fuels I would get 2 extra miles per gallon.
2 x 13 gallons(typical fill) = 26 extra miles
26 miles / 23 current mpg gives 1.13
1.13 x the cost of 87 gas ($3.00) is $3.39
So in this example you spend $2.86 to save $3.39 per tank
Net saving $0.53 per tank + all the benefits of the better fuel
Have a look at this calculation for 87 vs. 93 octane fuel for our 4.0 stangs and see if it seems right to you.
This is based on my typical running cost here in NJ
Example:
87 - $3.00
93 - $3.22
diff = $0.22
Typical fill for me is 13gallons
so, 13 x 0.22 is an additional $2.86
If I were to increase my typical 23mpg to 25mpg by changing fuels I would get 2 extra miles per gallon.
2 x 13 gallons(typical fill) = 26 extra miles
26 miles / 23 current mpg gives 1.13
1.13 x the cost of 87 gas ($3.00) is $3.39
So in this example you spend $2.86 to save $3.39 per tank
Net saving $0.53 per tank + all the benefits of the better fuel
2nd Gear Member
Joined: Mar 2006
Posts: 300
RE: MPG 87 vs. 93 Example calculation
difference in mpg between 87 and 91 tune is minimal. I ran 87 and switched to 91 and maybe .5 mpg improvement.
Please post your improvement considering you are still driving same road at the same speed.
Please post your improvement considering you are still driving same road at the same speed.
4th Gear Member
Joined: Apr 2006
Posts: 1,268
From:
RE: MPG 87 vs. 93 Example calculation
Again, to get a feel for scale, if you average, over all your driving 20 MPG, and you typically buy $2.89 87 octane and you are considering 93 octane at $3.09, the numbers are
Required MPG at 93 = 20 x (3.09/2.89)
Required MPG = 21.3
So for most people, with a range of MPG's and prices, you need between 0.8 and 1.5 MPG improvement.
The real question is this. What does this cost you per year?
By example
You drive 12,000 miles a year. You switch from $2.89 87 octane to $3.09 93 octane. Your MPG goes up from 20.0 to 20.5.
Real Cost Per Year = 12000/87mpg*87cost - 12000/93mpg*93cost
Real Cost Per Year = 12000/20.0*2.89 - 12000/20.5*3.09
Real Cost Per Year = $1808 - $1,734 = $74/year
Geez, with all the money I spend on this car, am I going to spend $74 a year for better performance? You bet. And that's only if the 93 octane makes 1/2 mile per gallon improvement
At 1 mile per gallon improvement, the numbers become
Real Cost Per Year = $1765 - $1,734 = $31/year
At 1.5 miles per gallon, I break even.
Required MPG at 93 = 20 x (3.09/2.89)
Required MPG = 21.3
So for most people, with a range of MPG's and prices, you need between 0.8 and 1.5 MPG improvement.
The real question is this. What does this cost you per year?
By example
You drive 12,000 miles a year. You switch from $2.89 87 octane to $3.09 93 octane. Your MPG goes up from 20.0 to 20.5.
Real Cost Per Year = 12000/87mpg*87cost - 12000/93mpg*93cost
Real Cost Per Year = 12000/20.0*2.89 - 12000/20.5*3.09
Real Cost Per Year = $1808 - $1,734 = $74/year
Geez, with all the money I spend on this car, am I going to spend $74 a year for better performance? You bet. And that's only if the 93 octane makes 1/2 mile per gallon improvement
At 1 mile per gallon improvement, the numbers become
Real Cost Per Year = $1765 - $1,734 = $31/year
At 1.5 miles per gallon, I break even.
I ♥ Acer
Joined: Apr 2006
Posts: 1,141
From:
RE: MPG 87 vs. 93 Example calculation
It turns me on when you get all mathmatical on us LX...Keep it up baby 
ORIGINAL: LX200
Again, to get a feel for scale, if you average, over all your driving 20 MPG, and you typically buy $2.89 87 octane and you are considering 93 octane at $3.09, the numbers are
Required MPG at 93 = 20 x (3.09/2.89)
Required MPG = 21.3
So for most people, with a range of MPG's and prices, you need between 0.8 and 1.5 MPG improvement.
The real question is this. What does this cost you per year?
By example
You drive 12,000 miles a year. You switch from $2.89 87 octane to $3.09 93 octane. Your MPG goes up from 20.0 to 20.5.
Real Cost Per Year = 12000/87mpg*87cost - 12000/93mpg*93cost
Real Cost Per Year = 12000/20.0*2.89 - 12000/20.5*3.09
Real Cost Per Year = $1808 - $1,734 = $74/year
Geez, with all the money I spend on this car, am I going to spend $74 a year for better performance? You bet. And that's only if the 93 octane makes 1/2 mile per gallon improvement
At 1 mile per gallon improvement, the numbers become
Real Cost Per Year = $1765 - $1,734 = $31/year
At 1.5 miles per gallon, I break even.
Again, to get a feel for scale, if you average, over all your driving 20 MPG, and you typically buy $2.89 87 octane and you are considering 93 octane at $3.09, the numbers are
Required MPG at 93 = 20 x (3.09/2.89)
Required MPG = 21.3
So for most people, with a range of MPG's and prices, you need between 0.8 and 1.5 MPG improvement.
The real question is this. What does this cost you per year?
By example
You drive 12,000 miles a year. You switch from $2.89 87 octane to $3.09 93 octane. Your MPG goes up from 20.0 to 20.5.
Real Cost Per Year = 12000/87mpg*87cost - 12000/93mpg*93cost
Real Cost Per Year = 12000/20.0*2.89 - 12000/20.5*3.09
Real Cost Per Year = $1808 - $1,734 = $74/year
Geez, with all the money I spend on this car, am I going to spend $74 a year for better performance? You bet. And that's only if the 93 octane makes 1/2 mile per gallon improvement
At 1 mile per gallon improvement, the numbers become
Real Cost Per Year = $1765 - $1,734 = $31/year
At 1.5 miles per gallon, I break even.