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Increase MPG by 2.9 mpg

27K views 135 replies 55 participants last post by  BikeBugger 
#1 · (Edited)
i recently did a 900+ mile 87 vs 93 octane mpg compar-o.. i averaged 2.9 more mpg with the 93 octane. works for me. :yesnod: i didnt include the mpg of the transition tank of fuel in the compar-o. so i accually rode a total of 1100 miles for this experiment. http://www.ehow.com/how_4911241_check-gas-mileage.html
one of the detonation (distortion) indicators when using lower octane fuel, is a drop in mpg. which is what happens to me every time i use 87 octane fuel. note: just because you dont hear engine ping doesnt mean it not happening. just means you cant hear it ping.
 
#3 ·
Depending on how you calculate your numbers, I don't believe you are saving $$$$ (maybe 1/10 of a penny per mile.....or something like that, assuming Premium Gas costs $0.15 over Regular??)......but you ARE getting more miles per tank full.....which could help out in the boonies/traveling cross-country. :thumbup:

(......and if you are "trolling" to get a debate going, I swallered the hook. line, sinker, and half the pole..........)

I would like to see someone create a spreadsheet covering 5-10 tankfulls of Regular vs. Premium Gas and the numbers generated.........????
 
#18 ·
... ... covering 5-10 tankfulls of Regular vs. Premium Gas and the numbers generated.........????
i did something like that last year. when i did a 3000mile low, middle, high-test fuel
compar-o. my results were middle grade better mpg than low grade, and high-test was better mpg than middle grade.
BTW, mpg experiments can be personal and informal. after all, we're not talking about subatomic particles here. IOW's try your own compar-o. find out for yourself. which ever grade fuel gives you the best mpg is going to be the best fuel for your bike.
 
#6 ·
I've had tanks full yielding anywhere from 39mpg to 62mpg on the same octane rating depending on conditions. 2.9mpg is not a scientifically significant difference with external parameters like speed, wind, temperature and air density uncontrolled. A double blind test with identical vehicles running together and switching octanes then riders during the test such that each vehicle, rider and octane combination would travel equal length legs would produce figures I'd be interested in. Even then, tank amounts would need to be better regulated than merely filling up for 2.9 to be a significant number.
 
#120 ·
As the man said, with one little addition: Not only that 2.9mpg is scientifically (statistically?) insignificant, it's also impossible. Higher octane number means more anti-detonation additives, ergo less power-producing fuel. Additives are not fuel and do not produce any power when burned (if anything, the actual fuel energy is wasted on burning them).

The only way higher octane fuel will yield better mileage compared to lower octane fuel is in an engine that requires higher octane fuel for proper operation anyway. Detonation (self-ignition) damages the engine, reduces power and wastes fuel at the same time.
 
#8 ·
You did do the math on that, right? A DL1000 gets about 40mpg and regular 87 octane gas is $3.39 a gallon, which is what it is right now that's 3.39/40 = $0.085 cents per gallon. Assuming $0.50 more per gallon for 93 octane, which is what it is around here right now, and that supposed 2.9 mpg increase, that's 3.89/42.9 = $0.091 cents per gallon. Exactly what part "Worked for you"?
 
#12 ·
I have randyos experience. My Vee will ping under load or heavy acceleration with 87 octane and hot temps. In the winter it doesn't ping hardly at all.

I am so indecisive I solved my problem by using mid grade 89 or so octane.

As for saving money....last I checked it was a bike. It eats a tire every 9,000 miles. I dream up reasons to ride it. I can do a 400 mile weekend and not even realize it.

I save money by not having to use a psychiatrist, that is what the Vee is for.
 
#13 ·
I save money by not having to use a psychiatrist, that is what the Vee is for.
abso-friggin-lutely!!!!!

even if the results are consistent, given a 5 gallon tank (minus reserve), you only yield 14.??? miles more per tankful. i guess it might save you if you cut fuel calculations VERY narrowly...
 
#16 ·
hard to tell - recommended might be best

Again I think Greywolf is right more similar miles might be needed. I don't trust small differences in my own mileage readings.

Performance is sometimes an indicator but that is I think hard to tell. I have come to concusion it is best to run what is recommended based on my old R80ST. The BMW counter guys told me I'd be better to run premiun even though manual said regular. I tried both and my pipe ran cleaner and better color with regular and it seemed to have better mid range pull with the regular - although hard to tell. With a cleaner pipe and no pinging I used regular. I figure that the combustion druation/timing was better suited to how that engine was designed.

My Wee pings occasionally on hills if I get on it. It is only mild so no fuel change for me.

I have had folks in cars tell me that they get better mileage with mid-octane fuel on trips - might be so I guess.
 
#19 ·
Oh my...

In the very best case scenario, an engine can extract the same amout of energy from super than from regular though super generally has less potential because the additives don't react as much as the fuel itself (that's what they're designed to do).

Then there's the little detail of compression: a higher compression ratio is required to extract the most energy out of super.

So, running super in an engine designed for regular will develop less power, which will yield less mileage. I don't think the performance difference would be significant, but the extra cost of the super might.

But since reality is usually never a best-case scenario:
The only thing super will do in an engine designed for regular is stop it from pinging and a non-pinging engine will make more power than the same engine if it is pinging since combustion in a pinging engine is necessarily incomplete.

IF you see better mileage with super, it's because your engine pings on regular, whether you hear it or not.

I found that my wee gets better mileage since I started riding in 4th and 5th on the highway. I've concluded that accelerating hard in 6th at 100km/h was causing the engine to ping.

Try using regular again, but shift down from 6th when you accelerate or ride uphill; I'm sure you'll see a fuel consumption difference, possibly a bigger one than by running super. My wee would consistently blink the fuel icon after 250 kms of commuting; since I stopped using 6th gear, it blinks around 320.
 
#20 ·
Actually

A little light ping is about the best timing available, so long as it doesn't get severe enough to start damaging your piston. Putting in premium to stop it (again light ping) will likely hurt your mileage. Of course, if your supplier uses a significantly different formulation (not ethanol) to get 93 octane, the gas may just have more intrinsic energy content per gallon. Might be kinda fun to weigh a precisely measured gallon of each. No use going into viscosity differences that might allow our blind FI system to provide a better mixture with one rather than the other. Of course, if yours is one of those enlightened states that think informing consumers of ethanol content constitutes too much information, then all bets are off. Oh, Nebraska is one of those states where it is hard find anything much above 91 octane without going to a racetrack or specialty supplier. And increasingly the 91 has ethanol in it, meaning energy content is way off. I suspect you could influence MPG a couple just depending on which jacket you wear, and whether it is tight and zipped or flapping in the breeze.
 
#21 ·
Putting in premium to stop it (again light ping) will likely hurt your mileage. I suspect you could influence MPG a couple just depending on which jacket you wear, and whether it is tight and zipped or flapping in the breeze.
i like your comments and i think there interesting but, i dont think you know what youre talking about. do a compar-o and find out for yourself. that way you'll have something to back up what you say. g-luck & ride safe.
 
#34 ·
Ya know, out of all of this, the takeaway I get is "darn am I glad the EPA uses an unrealistic formula for MPG rather than wading through all this muck!"

JRWalker, if you REALLY want to do this scientifically, you'll need to do multiple tanks with each octane level. You can use that to get the standard deviation (a measure of how much your samples change without changing octanes, due to things like temperature, how well you fill your tank, etc). You can then say "I want to test whether higher octane improves my milage with a significance of 90%," or whatever percentage you want (90%, 95%, and 99% are common in most sciences. 50% and 70% are common in ugly disciplines like psychology that need humans in the loop). There's some math you can crunch to see if you have actually proven that octane was significant. Actually, there's a TINY bit of math, followed by a few lookups in a table in the back of a statistics textbook!

There's a way to figure out how many tanks you need to prove it, but I got a D on that particular test in my statistics course, so you're on your own !:headbang:

If you want the non-statistical method do two things:
- Try 5-10 tanks (preferably 10) with each octane. Try your very best to fill them in the same way as much as possible. On a car (which is what eHOW was targeting) you've got a 14-20 gallon tank, so inaccuracy in filling is a lot less important than it is on a motorcycle tank. When I'm filling, I find my fill can vary by about 1/4 gallon just by how I hold the filler nozzle.
- Alternate octanes, to minimize effects like temperature changes
- Try to forget about the test when you're driving. If you think premium should improve MPG, you'll start driving more efficiently on the premium side and throw the results.
 
#35 ·
[...] You can then say "I want to test whether higher octane improves my milage with a significance of 90%," or whatever percentage you want (90%, 95%, and 99% are common in most sciences. 50% and 70% are common in ugly disciplines like psychology that need humans in the loop). [...]
Whoever taught you should have gotten the D, not you. I run an alpha of .05 in all my psychology experiments. That means that the difference between the experimental conditions has a 5% probability of occuring by chance; no self-respecting psychologist would expect to publish anything with an alpha of more than 0.1.
 
#37 ·
I use premium at all times, Chevron 94 whenever possible, because I do not want my bike to run on corn.

I can add 5KM per liter to my gas mileage on long slab runs by merely not having to accelerate through the gears....

3 mpg?? hahahahah!!! lower your shift point by a couple of hundred RPM's you will get that saving....


:beatnik:
 
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#40 · (Edited)
You've mentioned that before; you've also already said that it worked for you.

Here's a suggestion: increase your sample size (to at least 30 tankfuls) and report back to let us know if the increase in mpg is real.

Flipping a coin once and getting tails is not exactly a reason to believe that all coins will always land tails-up, is it?
 
#45 ·
Rather than continue with this "I get it, you don't" back and forth, I'll go away and let the readers decide.
 
#48 ·
i recently did a 900+ mile 87 vs 93 octane mpg compar-o.. i averaged 2.9 more mpg with the 93 octane. works for me. :yesnod:
Seems like they did a reasonable "compar-o" and came up with a reasonable conclusion. :thumbup:

It also seems like most of the other posters are trying to tell them their "compar-o" is flawed. :thumbdown:


How about this: Nice job on finding a way for you to get 2.9 more MPG's :hurray:
 
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