ECO-Fit DiscussionThreads discussing the pursuit of ultimate economy, hypermiling techniques & maximizing your MPG
Welcome to Fit Freak!
Welcome to Fit Freak,
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!
Around here this weekend regular is $2.49 and premium $2.69 per gallon.
Thats 8% increase in cost. In places its 30c per gallon more, or a 12% penalty. The difference between 32 and 34 mpg is 6%.
When you spend 8% more for gasoline to gain 6% in mpg, that isn't worth the money.
Engineer you may be, but an economist you ain't. That is misleading math you're doing there. What you want to determine is dollars per mile.
$per gallon, $2.49: divided by miles/gallon, 32: equals $0.078 per mile
$per gallon, $2.69: divided by miles/gallon, 34: equals $0.079 per mile
Not much difference -- or is it? Let's toss some miles in there so the numbers get bigger.
10,000 miles at $0.078 per mile equals $778.13
10,000 miles at $0.079 per mile equals $791.18
Still not much difference. The fact of the matter is that the cost of gasoline is a relatively small portion of the total cost per mile to drive a car. By far, depreciation is the greatest cost, followed by fixed costs such as insurance and maintenance. Next comes gas, followed very closely by interest on the car loan (if gas was $2/gallon, interest on the loan would be higher).
Bottom line: using the cost difference as a reason to use 87 octane instead of 93 octane doesn't really add up. And if you really, really want to save money on driving, buy old cars that don't depreciate and pay for them in cash.
Quote:
And true premium does burn slower, which is why static timing on premium fueled vehicles are more advanced than regular fuel specifications. But unless those premium fuel specified vehicles (BMW etc) are programmed to advance further unless spark knock is detected no advantage is gained but hp is. . Few cars specifying regular fuel have that programmed simply because the gain in hp isn't important..
It's already been shown that the Fit does indeed advance timing further when burning 93 octane than it does when burning 87. However the tests were performed at WOT, so there is still some question as to the benefit of higher octane under normal driving conditions.
It's already been shown that the Fit does indeed advance timing further when burning 93 octane than it does when burning 87. However the tests were performed at WOT, so there is still some question as to the benefit of higher octane under normal driving conditions.
If I can get the software sorted out (working on it now), I'm gonna log some 93 octane runs today . . . Hopefully be able to get some consistent part-throttle runs in as well as WOT. Gotta find someplace to do it, though. Then I'm heading on a trip tomorrow, so I'll burn through the rest of the tank & put 87 back in. Test w/ the 87 & repeat next weekend.
I feel I should repeat, though - just because ignition timing advances with the higher octane, that doesn't necessarily mean the engine is making any more power, or running any more efficiently.
Engineer you may be, but an economist you ain't. That is misleading math you're doing there. What you want to determine is dollars per mile.
$per gallon, $2.49: divided by miles/gallon, 32: equals $0.078 per mile
$per gallon, $2.69: divided by miles/gallon, 34: equals $0.079 per mile
Not much difference -- or is it? Let's toss some miles in there so the numbers get bigger.
10,000 miles at $0.078 per mile equals $778.13
10,000 miles at $0.079 per mile equals $791.18
Still not much difference. The fact of the matter is that the cost of gasoline is a relatively small portion of the total cost per mile to drive a car. By far, depreciation is the greatest cost, followed by fixed costs such as insurance and maintenance. Next comes gas, followed very closely by interest on the car loan (if gas was $2/gallon, interest on the loan would be higher).
Bottom line: using the cost difference as a reason to use 87 octane instead of 93 octane doesn't really add up. And if you really, really want to save money on driving, buy old cars that don't depreciate and pay for them in cash.
It's already been shown that the Fit does indeed advance timing further when burning 93 octane than it does when burning 87. However the tests were performed at WOT, so there is still some question as to the benefit of higher octane under normal driving conditions.
Yep.
You did the same math I did. Note that spending 8% more to gain 6% in mpg is a 2% loss; its is exactly the same as 778.13 vs 791.18 using your numbers. You just don't think saving a near tank's worth of refill per 10,000 miles is significant.
An economist says the $13.50 is significant because its money wasted. you didn't get your money's worth because you traveled only 12.64 miles per dollar instead of 12.85 miles.
If you were running a business thats very signicant. Again, its not the amount of difference its that you spend more than you get.
While gas is not the biggest portion of vehicle cost it is the largest of variable costs, the things I can do with my fleet that affect my costs. When I run 10 trucks at 5000 miles each per month, thats $67.50/mo (or $810 a year) I can put in profit that I wouldn't have. Add that to a hundred other things I kept careful tabs on amounted to probably $1000 per month my business didn't throw away. Or I had to charge my customers for unnecessarily. you need to sharpen your thinking on whats proper spending or I'll sic Clark Howard on you. LOL
Just where do you find the advance curves for Fits showing further advance when using premium? The ones run here shown them the same within one degree, our maximum margin of error. While there is a retarding program when spark knock is detected I find none that advances the curve when no spark knock is detected.
If I can get the software sorted out (working on it now), I'm gonna log some 93 octane runs today . . . Hopefully be able to get some consistent part-throttle runs in as well as WOT.
I'm looking forward to that!
Quote:
Originally Posted by mahout
An economist says the $13.50 is significant because its money wasted.
Meh. 13 bucks over 10,000 miles, that's a whole year for a lot of people. If putting premium in their cars gives them greater peace of mind, then it's worth it to them. My point is, and remains, that it isn't really that significant in the grand scheme.
That said, if someone really wants to spend a little extra on gas I still strongly advocate spending it on quality 87 before discount 93. For our cars, the additives in the brand name fuels are worth far more in terms of engine longevity that a couple points of octane ever will be.
Quote:
Just where do you find the advance curves for Fits showing further advance when using premium? The ones run here shown them the same within one degree, our maximum margin of error.
Daemione, I tried to use the Palmer download and it doesn't want to work citing Unregistered user..... I am sure that the results proved that there was some difference and probably enough to influence you to look at possibly wanting to start using 92 octane fuel or at least doing some more research before deciding not to..... I hope that there is some way for you to share your results as it is a topic that stimulates a lot of debate and is of great interest to those of us here that are pen minded.... European owners have claimed that their Fits are more powerful and get the best fuel mileage on 97octane fuel.
... European owners have claimed that their Fits are more powerful and get the best fuel mileage on 97octane fuel.
That is also true here but in Europe the cost penalty for using premium is much less economical thanks to $8 and $9 a gallon gasolines.. Its cents per mile that counts.
Octane rating and heats of combustion are not the same thing.
Honda designed the 1500 engine to use the most available gasoline around the world - 87 octane but of varying energy levels.
Daemione, I tried to use the Palmer download and it doesn't want to work citing Unregistered user.....
Go ahead and run it unregistered - it'll let you view log files without getting a license for it. I'm running it unregistered on my desktop, with the full version on my laptop.
That is also true here but in Europe the cost penalty for using premium is much less economical thanks to $8 and $9 a gallon gasolines.. Its cents per mile that counts.
Even if my mpg increase is zero, a 2 or 3 horsepower improvement is attractive to me. I'll somehow find room in my budget for the extra $2 once or twice a month . . .
But getting data that shows it actually results in extra power is going to be more involved. Maybe I'll check around my area for any events that might be running a dyno-day discount or something . . . run the car to almost empty on one grade of fuel, do some runs, then fill it up with the new grade & do a few more runs. And pray conditions are comparable between runs that day.
Even if my mpg increase is zero, a 2 or 3 horsepower improvement is attractive to me. I'll somehow find room in my budget for the extra $2 once or twice a month . . .
But getting data that shows it actually results in extra power is going to be more involved. Maybe I'll check around my area for any events that might be running a dyno-day discount or something . . . run the car to almost empty on one grade of fuel, do some runs, then fill it up with the new grade & do a few more runs. And pray conditions are comparable between runs that day.
Before I super charged my, car I was consisitently getting 37 to 39 MPG, mostly in the mid 38 mpg area..... This is driving the speed limit, slow and easy, where there are likely to be cops and 75 to 100 mph on stretches where I feel safe..... I was able to manage 33.7 when I filled up today but I am soft pedalling most all of the time, but when I get on the boost on occasion, it really kills my mileage average.
That is misleading math you're doing there. What you want to determine is dollars per mile.
Linear Mode
