Ethanol free gas and performance?

ASPC

ASPC

Joined
Jul 3, 2021
Messages
599
Location
Louisiana
Bike
07 ST1300 ABS
Has anyone noticed an increase in performance when using ethanol free premium fuel?
At the moment I haven’t used it enough to tell if it’s just in my head or not.
But its got me wondering how much ignition retard the ECM is using when running 10% ethanol.
My bike also runs just fine on regular gas with ethanol all due to the ECM.

The first thing I have noticed is an increase in fuel economy, which unlike perceived seat of the pants performance increases can be seen and measured.

The difference appears to be significant.
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I had a very noticeable increase in power when running ethanol free premium in a 2012 Super Tenere when given wide open throttle. I also was using the clutch fuse bypass which alters timing in the first few gears.
 
I definitely see better mileage when using 91 octane no-ethanol gas, something like ~10% over using 87 which always has ethanol in it. I know that is not apples-to-apples. And the engine runs smoother.
 
10% of your fuel is getting you 20% less power and mileage at best. In the recent past, ICE's were expected to transition to 20% ethanol. Haven't heard much about that recently, what with the push for EV's.
 
It's about time someone put their bike on a dyno and tested this out for a specific model - our ST's. Speculation and anecdotal seat of the pants evaluations don't cut the mustard.
 
I didn't think about the difference in mileage between the ethanol and non-ethanol gas but I did fill the tank with non-ethanol two weeks ago before doing a 300 mile around the thumb of Michigan. When I I had to refill, I calculated almost 50 mpg. I didn't baby the bike nor did I do hard accelerations, but I may have been traveling above the posted speeds once or twice. :) That mpg was a couple of miles better than I normally get using regular 87 octane.
 
As a contrast to others, I have almost always used e10 in all my bikes from my GW to ST1100, CTX1300, Burgman 650 and my AK 550. All of those only needed 87 octane and in central Iowa the most common available is e10. Don't know how much difference there would be in a bike that is made for premium gas like the ST1300. Non-ethanol gas is around but much more effort to find, and then no guarantee that it really is non-ethanol. Most gas stations in Iowa have some ethanol content but don't need to put that sticker on the pump if it's under a certain %. Back in the '80s I tested the difference in my car since I was riding about 35 miles one way for the commute and was mostly Interstate. One month non-ethanol and one month with ethanol with all the same driving conditions. No difference in gas used, mpg, or performance was noted. When I travel to events I do find more gas stations that have non-ethanol (or very low ethanol) since I just fill where I need to fill while traveling. I find little to no difference on any of my bikes going back and forth with e10 and non-e10. Though I don't ride as hard and fast as some riders so that may be the difference. Maybe more of a difference when operating near the end of the envelope of performance but I never see that.
 
Walleye said:
Dyno Shmyno, it takes 1.5 gal of ethanol to equal the btu of 1 gal of gas.
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I'm not arguing your point, however, there is a difference between theory and practical application. We know eth has a lower energy content, and can easily calculate what the reduction in mileage, power, etc. might be for gasahol, but do the bikes know that and actually deliver 2% less power on 90/10 or are they unhappy to the point that they deliver 5% less power and mileage? Inquiring minds want to know.
 
I didn't look it up until after getting some really bad ethanol from a local station. I had been running "regular" gas for the most part, and wasn't always able to buy the non-ethanol gas. However there have been quite a few studies/comparisons with motorcycles (search "ethanol vs non-ethanol gas motorcycles) There are some mixed opinions, but the majority show improvements. Mind you I don't remember seeing any that were ST specific. But it seems that the evidence points that direction.
 
rjs987 said:
As a contrast to others, I have almost always used e10 in all my bikes from my GW to ST1100, CTX1300, Burgman 650 and my AK 550. All of those only needed 87 octane.
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Just for clarification. Does the CTX require only 87 octane per the honda spec. I only ask because it has the same engine as the ST13, which requires 91 octane. Which hardly anyone sells.
 
Does anyone have actual PERSONAL DATA regarding the 1300 and non-ethanol as regards recorded gas mileage?
Many of the posters here ride the ST1100, if I'm not mistaken.
I would anticipate better fuel economy, but have no proof.
I can buy regular and premium "pure gas" at Bucc-ees, but it would take almost a gallon of fuel to get there.
TIA.
 
etalors said:
Just for clarification. Does the CTX require only 87 octane per the honda spec. I only ask because it has the same engine as the ST13, which requires 91 octane. Which hardly anyone sells.
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Yes, one of the minor changes to the engine was the compression being lowered. That and a few other even more minor changes resulted in Honda specifying 87 octane for that version of the engine.
Acceleration was diminished a little due to different throttle bodies but torque and HP were boosted to be higher than the ST1300 down between 1800-4000 rpm as a result of all the changes. I could run at 30-35 mph all day in 5th gear without lugging the engine, and have enough grunt to easily accelerate up from there. If I didn't have to stop I'd get into 5th gear and just leave it there the entire ride.
 
Sadlsor said:
Does anyone have actual PERSONAL DATA regarding the 1300 and non-ethanol as regards recorded gas mileage?
Many of the posters here ride the ST1100, if I'm not mistaken.
I would anticipate better fuel economy, but have no proof.
I can buy regular and premium "pure gas" at Bucc-ees, but it would take almost a gallon of fuel to get there.
TIA.
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Mileage is a very slippery beaste. Regardless of how hard we try, there are too many variables in everyday life. First of all, do we fill the tank to the exact same point, using the same pump? How accurate are the pumps, and what about the quart to half a gallon that we pump that is the gas pumped by the previous customer? Your mileage will be affected by your route, speed, winds, hills, etc.

I try to keep every receipt for gas that goes into my bikes (and cars) and I enter the info on an Excel spread sheet. Despite trying to be as accurate as possible, my mileage varied somewhat from year to year. I think I was riding faster on freeways for the last three years, but otherwise cannot explain the difference. I regularly alternated between 91 and 87 octane to try to average what Honda wanted, and usually filled up at half a tank.

Here is my data by year, and the miles were distance covered that year:
2014 4681 mi 44.54 mpg
2015 3408 42.15
2016 4216 39.90
2017 5081 39.72
2018 5056 39.60

Based on my experience with my ST, and the fact that my VStrom's numbers similarly vary, I think that picking up a difference of a few percent by using gasahol vs gasoline would be extremely difficult.

If you wanted to do the test, one would have to control for as many variables as possible. For example, you could yank the fuel tank and hang a fuel bottle next to the bike, which is strapped to a dyno, carefully measure the fuel that goes in the bottle, verify the accuracy of the rear tire's circumference, record ambient conditions, and run the bike on the dyno for several carefully programmed accelerations, decels, maybe even stops, or a steady 60mph. Then repeat for your other fuel. This would eliminate wind resistance, but would give a baseline improvement (either pos or neg) using 100% gas. It's probably not going to happen.
 
I only buy non-ethanal gas when I know my bike is going to sit for any amount of time. Other than that I can detect no difference in idol, power, or MPG when running E-10.
 
I get significantly better MPG using non-ethanol gas. However, it also costs more per gallon here in the Seattle metro area. You will have to do the math to see if it's actually worth paying more for the non-ethanol gas. It's about even when considering the cost difference vs. mileage earned with non-ethanol gas. The only long term consideration would be the impact on the motor over time and if there's any mechanical benefits.
 
I think that a bigger difference would be noticed with a ST1100 and it's carbs than a ST1300 with it's fuel injectors (presuming the FI system makes adjustments). All four of my ladies are lot happier when they get the pure stuff - which ain't very often as there are very few places around me that sell the stuff without the corn squeezings in it.
 
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