Subaru Outback Forums banner

Status
Not open for further replies.
41 - 59 of 59 Posts

·
Registered
'03 Outback H6-3.0 Black Granite Pearl, base model with cold weather package and cloth seats.
Joined
·
1,053 Posts
I thought the adoption of ethanol as a gasoline additive was to replace MTBE as an oxygenate, used to minimize ozone production in the atmosphere. MTBE was getting into ground water, and there was a movement to replace it with something safer and more environmentally friendly. There certainly was political input into ethanol's selection over other options, but I believe moving away from MTBE was the prime focus.
 

·
Registered
2019, Subaru Outback Limited 3.6R
Joined
·
908 Posts
Correct!
 

·
Registered
Joined
·
100 Posts
Discussion Starter #47
I would think that if 85 octane gas is bad for your car, there would be higher repair rates in the states that it is available. It is not a case of people avoiding using it, in CO 80% of the gas sold is 85 octane, 9.5% of gas sold is 87, and 10.5% higher. I first used it back in 2003 when taking a trip to CA. I may have used it earlier but don’t recall. So it has been around for a long time. Modern vehicles adjust their timing to the octane level (knocking) so the only result should be less power and mileage, but my experience is that I get better gas mileage in the Mountain states regardless of the vehicle I drive. Yes, you are climbing, but it is a free ride going down.

In the case of E10 vs. E15 all the studies I have seen show there is little difference in performance. The slightly lower energy content (2%) of E15 is offset to some extent by the increased octane which modern vehicles adapt to by advancing timing. Interestingly (to me anyway) is that three of Subaru’s vehicles now allow E15 to be used, yet it does not appear to me that the engines are new. What’s new is the owners manual, these are new vehicles.

BTW, both E10 & E15 are blends of alcohol and 84 octane gas, resulting in 87 and 88 octane
 

·
Registered
2016 Outback Premium 2.5 CVT w/EyeSight+SRVD
Joined
·
6,842 Posts
I would think that if 85 octane gas is bad for your car, there would be higher repair rates in the states that it is available. It is not a case of people avoiding using it, in CO 80% of the gas sold is 85 octane ...
85 AKI fuel is the default in mountain states because the lower air density due to altitude reduces the octane requirement for normally-aspirated engines. (On the other hand, turbocharged/supercharged engines still require the same octane rating as at sea level.)

What’s new is the owners manual, these are new vehicles.
Nope. What's new is ECM calibration for each new engine/vehicle type. Some fuel system components may be different, too ... e.g. higher flow rate injectors. The Owners Manual simply reflects the technical differences.

For small changes like E10 to E15, a manufacturer might simply run qualifying tests to establish that the E10 fuel system is capable of running E15 without modification. In that case, the Owners Manual and vehicle placards might be the only changes.
 

·
Registered
2016 2.5i Limited, 2013 Tesla Model S 85
Joined
·
1,052 Posts
90% of the gas sold in CO is 85 octane, so people are voting with their wallets. I believe it is only sold in CO, MT, WY, & UT. Many stations do not sell 87 octane gas because nobody wants it. So if there is something wrong with using 85 octane, you'd think these states would have higher than normal engine breakdowns.
I have never noticed pinging coming from my engine while using it. You'd think with all the elevation gains, somewhere along the line I'd notice pinging.
85 octane rating at elevated altitudes is perfectly in spec for 87 AKI rated engines.

The most unexpected place I have seen 85 AKI was in Dayton, OH. The elevation does not justify.

“85 octane” used to mean 85% iso-octane, 15% iso-heptane. Gasoline is a cocktail of many different hydrocarbons so we use ratings to compare equivalent function. There are 2 accepted standard test engines+procedures, Research, and Motor. In USA we buy gasoline labeled (R+M)/2, the average of the two, combination labeled as AKI, Anti Knock Index. Europe and much of the rest of the world uses only the Research number, labeled RON, Research Octane Number
 

·
Registered
Joined
·
12 Posts
Interesting discussion. I'll relate (again) the experience I had with E10 and E0 fuel my 2000 V6 Camry (with 5-speed MT!)

When it was new, I was getting mileage around 27 mi/gal on a tank when the bulk of the driving was my daily 12 mile, twice a day commute, about half on free-flowing highway and the rest not terribly congested city driving, with short lunch trips and a few putz-around-town trips, filling up about once every two weeks. This was very repeatable over a span of years. Then, I noticed that I was no longer getting that mileage - it had dropped rather abruptly to between 24 and 25 mi/gal for several tankfuls with the same driving pattern, and stayed there.

A while later I had forgotten to get gas when I meant to, and was at lunch with a nearly-empty tank. The mom-and-pop gas station next door had a sign "100% Gas! No Ethanol!" It cost more (20¢/gal, as I recall, less than 10% higher) but I really needed to fill up and get back to work, so why not? The mileage from that tank was back to 27 mi/gal. Hmmm... that's interesting.

Next time, I had filled at the usual place, noted the "May contain up to 10% Ethanol" sticker on the pump, and got about 25 from that batch. Filled with E0... 27. Filled with E0 again, and again got 27. At this point I started to routinely use E0 if practical, and the mileage stayed at 27 for those routine tanks, dropping consistently by about the same amount when I did use E10. I was literally getting 8 to 10% better mileage with the Ethanol-free gas, and noticed that the car seemed to like it better - it ran smoother - too, for a price around 8 to 10% higher. This went on for several years until the price of E0 increased rapidly to about 40¢ over E10, at which point it no longer made economic sense to me, and I mostly quit using it.

When I traded the Camry in for the 2015 Outback, I tried a few tanks of E0, even at the much higher cost, but did not notice any change in mileage at all. By then I was retired and my driving pattern was much more varied, so the tank-to-tank consistency was gone. Still, over several tanks I was pretty sure I'd see a difference if it was as large as with the other car, but nada, so I never use the stuff now.

I'm not sure what it was about that Camry, but it did not like gasoline with Ethanol, and for a while E0 was priced so that it was a no-brainer! YMMV.
I had similar experiences with motorcycles. I try to never use ethanol laced fuel in my motorcycles. They sit too long, the gas goes ‘sour’, and I had one gas tank perforate due to water absorption. Mileage; consistently 10% less with 10% ethanol. The idea, I think, is to save gasoline by diluting it with alcohol. However, if I get 10% less mileage I’m still using the same amount of gasoline. IMHO, it’s all a boondoggle to shore up the corporate corn industry. From everything I’ve been able to read, E15 is horrible on small engines and is not supported by the motorcycle industry. Got an old classic? Fagitabowdit
 

·
Registered
2011 Outback 2.5i; 2017 Outback Touring 2.5
Joined
·
42 Posts
I don't think it's a much about whether the vehicle will run on E10 or E15, but what damage that extra ethanol level will do to the seals, gaskets, fuel lines (if internally coated), plastic gas tank parts, fuel pump, injectors, etc. FlexFuel vehicles are built so that their fuel systems don't disintegrate with different types of fuels and they easily handle high ethanol ratings, up to E85.

I have both a Honda-powered generator and a Honda-powered powerwasher, and their owners manuals expressly state NOT to use any gasoline higher than E10. They run fine on E15, but its what it does to the fuel delivery system that is of concern. Many of these carbs use plastic floats and other parts, synthetic gaskets, etc. There is no remedy for this, unless I go to the local airport and guy some AvGas, which is not subject to federal and state roadway taxes (so it's illegal for use in automobiles that travel public roadways).
 

·
Registered
2020 OB Limited, Titanium & Magnetite Grays
Joined
·
545 Posts
A Summary of what was previously written here and what I know about this subject

  • 85 Octane is for high (well above sea level) altitudes. Since the air density is lower the intake stroke takes in fewer air molecules. Then during the compression stroke there is a lower volume of air resulting in a lower compression pressure.. Lower compression can run lower octane without the knock. This is applicable to high altitudes such as the Rockies. Lower octane run at sea level may not knock due to modern sensors and computer controls but performance will suffer. Before modern sensors lower octane gas was sold at higher altitudes and owners that lived at these altitudes sometimes rejetted their carburetors for better performance and less carbon build up..
  • As previously stated, adding 10% ethanol lowers the energy by 3% by volume. The math is based on the fact that ethanol contains ~30% less energy than gasoline by volume. The math concludes that on average of all vehicles the mileage will drop by 3%. Gasoline supply chain will be selling 3% more fuel. With estimations of a fixed refining overhead there is a real economic motivation to add ethanol. State governments get a 3% increase in gas tax revenues so they are benefiting from the addition of ethanol. In CA this is a lot of revenue.
  • Ethanol is corrosive, let me say it again ethanol is corrosive. Therefore E15 is 50% more corrosive than E10 due to ethanol. I believe that when manufactures say their vehicles can run up to 10% ethanol that suggests the fuel system contains materials that should be able to withstand this mixture for an expected life time. Running E15 in a system designed to handle E10 is expected to have an earlier failure, on the average, than a system following the manufacturer's specification. You may not see the result of a decision to run E15 but keep the vehicle long enough and...
  • Ethanol raises the octane of gasoline. Starting with a lower octane gasoline costs the suppliers less money to make the gasoline. The octane is then raised by adding more expensive ethanol and at the same time they sell more, 3%, fuel.
 

·
Registered
2016 Subaru Outback Limited, 2.5l CVT
Joined
·
27 Posts
I can also attest to this. I had a 2004 Suburban that I drove on long hwy trips for my business. Unless I was pushing it I always averaged around 20 MPG. Go forward a few years and all the sudden my MPG's dropped. Driving the same way I was struggling to get 18 MPG. Changed spark plugs, etc. No change. Then I found out almost all the gas that was available to me was E10. GRRRRR! I'm still so anti ethanol if I was a terrorist there would not be an ethanol plant in this country that was not smoldering. Add to that making all my small engine yard tools throw away every year or 2 as the stinking fuel system parts are priced through the moon. Ever priced 1 of those little primer bulbs ya pump to start 1? Should a dollar part, last time I priced 1 it was $15.00!


:devilish:
Buy your primer bulbs on Ebay. Much cheaper. Can also buy in bulk. Ali Express is also a good place to buy if you can wait a month for delivery from China. I know. I know. They are all made in China anyway.
 

·
Registered
2008 Outback H6 LL Bean , 94 Ford Aerostar
Joined
·
115 Posts
I thought the adoption of ethanol as a gasoline additive was to replace MTBE as an oxygenate, used to minimize ozone production in the atmosphere. MTBE was getting into ground water, and there was a movement to replace it with something safer and more environmentally friendly. There certainly was political input into ethanol's selection over other options, but I believe moving away from MTBE was the prime focus.

Yes the MTBE was the problem but the refiners went to the CARB and said we can make the Calif gas without an oxygenate so lets just do that. But federal law requires an oxygenate so an exmeption was applied for to the Feds and it was denied forcing Calif refiners to go with the ethanol, pure politics nothing else !!!
BTW I run pure gas, low octane but no additives nor ethanol in my 7000 Honda generator and with the fuel injection motor it gets more run time per tank and lasts a long time. It's costly compared to pump "gas" but worth it to me. I get it in 5 gal cans well sealed, no longer afraid of PG&E , well blackouts anyway :) .
 

·
Registered
2008 Outback H6 LL Bean , 94 Ford Aerostar
Joined
·
115 Posts
What happened to the EDIT button???
Well, I meant to put a comma between sealed and no.
 

·
Registered
Joined
·
313 Posts
What happened to the EDIT button???
Well, I meant to put a comma between sealed and no.
The 3 vertical dots, on the right/top side of your post.


edit: Also, watch where you start typing. You need to be at the BOTTOM of where you're typing, otherwise your reply ends up in the quoted area.
 

·
Registered
Joined
·
100 Posts
Discussion Starter #57
A Summary of what was previously written here and what I know about this subject


  • As previously stated, adding 10% ethanol lowers the energy by 3% by volume. The math is based on the fact that ethanol contains ~30% less energy than gasoline by volume. The math concludes that on average of all vehicles the mileage will drop by 3%. Gasoline supply chain will be selling 3% more fuel. With estimations of a fixed refining overhead there is a real economic motivation to add ethanol. State governments get a 3% increase in gas tax revenues so they are benefiting from the addition of ethanol. In CA this is a lot of revenue.
  • Ethanol is corrosive, let me say it again ethanol is corrosive. Therefore E15 is 50% more corrosive than E10 due to ethanol. I believe that when manufactures say their vehicles can run up to 10% ethanol that suggests the fuel system contains materials that should be able to withstand this mixture for an expected life time. Running E15 in a system designed to handle E10 is expected to have an earlier failure, on the average, than a system following the manufacturer's specification. You may not see the result of a decision to run E15 but keep the vehicle long enough and...
  • Ethanol raises the octane of gasoline. Starting with a lower octane gasoline costs the suppliers less money to make the gasoline. The octane is then raised by adding more expensive ethanol and at the same time they sell more, 3%, fuel.
nice theory, but you are forgetting or neglecting to say that the increased octane rating offsets some of the loss due to the lower energy content, that is not theory, that is fact, modern engines adjust to the fuel, studies have shown that the loss of power/mileage is closer to zero than 3% you have stated.

secondly, I have listed the car manufacturers that have approved E15 for use, it is the vast majority of autos made, the notable exception, notable because this is the Subaru OUTBACK forum (not the Suburban Forum, not the lawn mower Forum, Not the classic motorcycle Forum, ...) again, I have not been able to find any study showing an increase in failure, only studies that show no difference in failure, saying E15 is 50% more corrosive is totally fake news, a 50% increase to zero is zero

there might very well be a good reason Subaru does not approve E15, it could be connectors that cannot withstand a simple increase in alcohol content, it could be a polymer, or it could be that Subaru, being a small company, just didn't apply the resources to find out. Since not many people use E15, they didn't bother with it. But notice that new models do allow for E15, and they use the same engines as other models. There could be new parts involved, but that is only speculation, where is the proof? Subaru isn't going to call out new parts just to allow for using a gas almost nobody uses, that is contrary, auto companies try to use the same parts as much as possible.
 

·
SubaruOutback.org Founder
2018 Outback Limited 2.5L - 100,000+ miles
Joined
·
4,913 Posts
@ArF193 requested that I add this, thread will remain closed.



Label required on pumps that dispense E15. Label reads as follows: ATTENTION. E15, up to 15% ethanol. Use only in (1) 2001 and newer passenger vehicles (2) flex-fuel vehicles. Don't use in other vehicles, boats or gasoline-powered equipment. It may cause damage and is prohibited by Federal law.'t use in other vehicles, boats or gasoline-powered equipment. It may cause damage and is prohibited by Federal law.

It is important to note that dispensing E15 into a vehicle or engine that may not use E15 is prohibited by federal law.



Sorry, but I stand by my statement there is a 3% loss in mileage when running E10 compared to E0. Ethanol has 30% less energy, by volume, than gasoline. The math: 30%*0.10=3% less energy..

Octane has nothing to do with energy.



Corrosion References

Oak Ridge Labs: aluminum is most vulnerable to extensive corrosion in ethanol environments having trace water concentrations

Ethanol's role in corrosion

Ethanol as a carrier of corrosive compounds

Pitting corrosion of stainless steel in ethanol/gasoline blends studied

Ethanol is corrosive in a fuel tank made of metal

.gov site reports about corrosion of steel in petroleum pipelines and storage tanks



Fuel Economy References

The Environmental Protection Agency says E10 lowers mileage approximately 3 percent, which would drop your mileage from 19.6 to 19.0 mpg

US Gov Says: vehicles will typically go 3% to 4% fewer miles per gallon on E10 and 4% to 5% fewer on E15 than on 100% gasoline.

EIA: Vehicle fuel economy may decrease by about 3% when using E10
 
41 - 59 of 59 Posts
Status
Not open for further replies.
Top