It's more likely these "people" aren't so good at math or accuracy of the basic information. I've been using pure gas from several different locations in the north west in 3 different vehicles and basically see 10% difference between pure and E10. This is a welcomed benefit of pure 92 in my land rover which on E10 does well to get 16-18 mpg. I now see 18-20. It's almost tolerable! It seems that on a GSA, you'd have a fuel range difference of almost 50 miles but my rover has 2 tanks for a total of 50 gallons so my fuel range difference is almost 100 miles. A BMW sales person told me the E10 causes some issues when a bike sits too long...
I don't know where the 3% comes from but lots of numbers are doctored to prove invalid points. My numbers were gallon of pure gas to gallon of pure alcohol. Gas has more energy than alcohol period. I get about 10% better mileage every time I use it. After a whole bunch of chem labs in college I know how to run an experiment and come up with apples to apples. I didn't mention this before but I get way better throttle response too.
You're correct that gasoline has a higher energy content per gallon. You can look it up and it's a matter of fact. In a 10% blend, gasoline with mtbe has 2% less energy per gallon and gas with ethanol has 3% less energy per gallon. To get the appropriate amount of fuel for a given amount of air, the injection times need to be 4% longer for 10% ethanol or the fuel pressure needs to be about 8% higher. Obviously, I can't speak to what you get in your vehicle.
Here is a good starting point. http://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf If you look at page 2 you can see that gasoline has 124,340 BTUs per gallon. E100 (pure ethanol) has 84,530 BTU/Gal. So E10 is (.9*124,340)+(.1*84,530)=120,359 BTU/Gal.. Then to see the % difference: 124340 / 120359 = 1.03307. So 124.3k is about 3.3% more energy than 120.3k. Now I don't want to claim more knowledge than I have. Its very possible that due to many things such as ignition point, burn speed, etc, that an engine designed for gasoline can't effectively utilize all those BTUs. Some ethanol may not burn completely, or it may burn in the exhaust providing heat but not power. But the above is where the 3% number comes from. EDIT: I just noticed that that chart has a "lower heating value" and "higher heating value". I honestly don't know what that means, but if you do the same calc with the lower numbers you get a 3.5% difference, so the same basic ballpark. Geof
agree...there are a lot more variables that go into the heat extracted from the fuel in an IC engine cycle than just LHV (or HHV) of a fuel...valve timing, fuel flow, ignition timing, engine speed, flame speed, etc. As an example, that chart shows a 113% increase in heating value of diesel compared to pure gas, but we all know how well that works in a gas engine Im assuming there is a reason that top-fuel dragsters run alcohol based fuels instead of pump gas.
I totally agree with you about the variables. Back in the muscle car days when you hit 10:1 compression ratio you had to go to premium or it detonated. Head design made 10:1 and higher run on regular, depending on the engine. For a long while 1 HP per Cu In seemed like a rock wall, no more. A lot of that had to do with studying flame fronts in the combustion chamber. Gas and ethanol burn differently. Size of valves, number of valves, valve shape, head shape, etc, etc all affect the flame front. If this conversation is to mean anything you have to talk apples to apples. To get there, despite the basic numbers, you need to take stock bikes and put them on a dyno and compare graphs of gas against E10 / Exx. Then do mileage tests over the same course and conditions. Until that happens, my assdyno says gas runs better than E-whatever, but only for driveability. Mileage, every time, straight gas gets better mileage. Last thought, the Brazilians have done a lot of work using Triumph Tigers, probably because they are easy to remap for both A/F and ignition. They had to remap from idle to redline for various mixtures of ethanol. I used several of those maps. What they all had in common was mileage went down significantly.
We go out of our way in this house to use the ''pure gas''. Every vehicle is has a log about its oil & filters, tires & mpg tell quickly when some is about to go wrong . Across the wide range of different vehicles the MPG have increased. Some as high as 16%. The lowest is STILL in the J-20 Jeep truck. We pay about the same cost as the high test fuel. Sometimes pennies more a gallon. The vehicles that sit up for weeks w/o being ran around never NOW have a starting issue. We never use a fuel additive, anymore. Fuel additives are not free & when factored into the cost of a tank of fuel the miles per dollar drop. All vehicle tanks are kept full when not used.
Here's a article that Cycleworld just put out on the subject : http://www.cycleworld.com/2013/07/05/everything-you-need
Garmin's latest software update for the POI Loader broke the proximity alerts option for custom POIs in case your wondering why it no longer works. Garmin 665 in my case and Windows 7 - 64 bit. I habitually return to Pure-gas.org to get their latest POI file and update my Garmin 665 with it. That way if I go out of my area I can get a heads up on non ethanol stations which I try and hit if I can while on a ride. Anyway I just spent a good hour and a half with support and their software team is aware of it - they took a sample csv file for testing and hopefully will get a fix in shortly. In the mean time you can call Garmin to get their previous version of the POI Loader program if you need the proximity alerts enabled again. It's around 12 megs. I have it (windows version) but I don't have a big file share site or program... and I'm not sure if regular email will handle that... really doubt it. Garmin will set up a remote sharing to get the file.
At the fire station we use it for our small engines, fans, pumps, chainsaws, etc. They run great on it but if the fuel system isn't airtight i.e. vented caps, the pure gas evaporates very quickly for some reason. A full tank in a pump can be half full in a month. I don't know why this is but it happens.
I fill up with ethanol free gasoline anytime I run across the stuff, but I'll be honest in that I can't really tell any appreciable difference in performance either way.
I can't either with my later model vehicles that I have. But I've got a '93 work truck and all of my small gas engines that literally loves that stuff. So I try and make it a habit on the GSA. My guess is the later model fuel mappings can handle ethanol better than the earlier ones. And I fill my stuff up with this for winter storage to help prevent issues later. -Edit- I work with a couple of people who have paid good money to clean their carburetors out on their fishing boats running ethanol gas who now have switched.
I just installed an APP on my iphone called Pure Gas and it gives locations and directions to stations nearest me. I cross refrenced to the Pure GAs map posted earlied and it looks the same. Handy........
Here's a Link to Google Play for the Android version - phone application... tablet???? Don't know about that one. It's free
I'm not sure if by the term performance you included burn rate or just meant throttle power. I use ethanol free up here in da north exclusively. I did the grand tour of the US of A last July and filled with whatever crap gas was available when the tank was low. I can tell you for certain my MPG dropped significantly. The fuel burn rate readout on the dash was always lower and the kms per tank were always less than the ethanol free good stuff.
