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The big Ethanol debate....

7K views 30 replies 9 participants last post by  XJman 
#1 ·
Looking for opinions on which would be better for my new 2017 WRX. It is NOT a daily driver so a tank of gas lasts me a month or 2 at least.

93 Octane premium fuel with Ethanol

OR

89 Octane Non-Ethanol fuel

Aaron
 
#2 ·
Are you kidding?

93 w/ 10% ethanol has much higher AKI.

Your car requires 91 octane IIRC.

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#5 ·
I always wondered why does everyone say "ZOMG!!!111! that fuel has 10% Ethanol, its Uber Crap!!" when essentially it's just that.... ethanol, great for suppressing knock. Are they worried what a measly 10% ethanol will do to their fuel pumps and fuel lines?

Just saying because the more pricey gas stations here boast having less ethanol like it's a good thing... and here I am like :confused1
 
#8 ·
And it also could be that in some older cars' owner manuals people are used to seeing something like "do not use fuel with more than 10% ethanol" and folks recall seeing such a thing but do not recall the actual number and haven't actually read their newer manuals (like our WRXs) to notice they no longer say such a thing.
 
#9 ·
I mainly worried about it sitting in my tank for an extended period causing phase separation or water accumulation in the fuel. I run Non-Eth in my boat for that reason. Sorry for the stupid question, I was just trying to find out what everyone thought. 93 Octane ethanol it is. I thought this forum was about asking questions.
 
#12 ·
Ditto for 2-stroke engines which you may find with chainsaws and snowmobiles . . . and it was more of a concern for folks running older two stroke engines . . . but it's less of a concern now for the most part (although some places like to blame just about every problem on the ethanol). It is however more of a concern when it comes to long-term storage, such as leaving your sled full of gas for the spring, summer and fall (although this issue can be remedied with some stabilizer, such as Phase Out or Star-Tron.)
 
#11 ·
I only have the choice between 93E10 and 91E0 now. I run the 93.

Years ago, we had a few options of 93E0, and a few of us locally did some experimentation on MPGs. As a collective, over many different tanks, being driven in typical fashion (we weren't counting tanks with Auto-X events), we would see 1-2 MPG higher out of the ethanol-free.

Back when the experiments were ran (and 93E0 was available), I was driving 15K miles/year. I could postpone my hoonage as to not affect my results. I'm only putting 150-175 miles/month on the car, so I have pretty much made the conscious decision that even if we get 93E0 back again, unless I'm going to be driving the car for a significant time (e.g., the truck is down for repairs for two weeks), I'm staying with 93E10.

There was a comment about small carbureted engines; I always used to use whatever regular pump gas was. I made the switch over to 93E0 (when it was available), and now continue with 91E0. When serviced in the off-season, I'm glad I spend that little extra money throughout the year.
 
#14 ·
I run strictly Non-Ethanol in all my lawn equipment. Also my boat which has a 90hp 2 stroke. I was mainly worried because I know the Ethanol fuel breaks down a lot quicker and I will only be driving 100-200 miles per month. I didn't want bad fuel ruining my engine.
Aaron
 
#19 ·
There hasn't been a vehicle past the mid 90s that didn't have ethanol based fuels in mind. They actually began addressing the issue years and years prior with the "gasahol".

As far as practical, making substantially more power easily and more safely. It's actually going to have fewer adverse affects than gasoline itself.

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#21 · (Edited)
Pretty sure there was some mention of power, and some excuses in there.

Not a "witch hunt". I simply won't run it. However many times "tuners" rave about power and "good but. . ".
My car will get a new fuel system as part of due maintenance. And a tunable ecu + injectors and such. Out with the old. In with the new. But looking for a moderate, reliable and consistent gain in hp. No plans to run the corn juice.

Hard for those on the bandwagon to understand. It's an unnecessary hurdle to make streetable power.

And how dare you sir. :wiggles: my car is still 16. Not 20+ years. -dec 1999. Not an "old car" at all.:confused1
 
#25 · (Edited)
:bs:

So i filled up my tank with "Hi-Oc". And asked the attendant. Yo, what octane number is this stuff? He says it's 100. Yup. That is why my car is happy. Drinks the good stuff.;)

Keep your corrosive dry fuel that likes water.
 
#28 ·
100RON would probably be closer to 95 (r+m)/2 in terms of AKI, but your point stands.

I seem to recall pure Ethanol is close to 112 (r+m)/2 based on analogous anti-knock.

Yes, E85 is corrosive, but not any more so than normal petrol. The hygroscopic properties of ethanol does place real concern on fuel tank rust, but it sounds as though additives are available to suppress this problem.

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#30 ·
I'm not sure. I know my WRX had a polymer lined tank, as does my STI. I can't comment on a 1998 STI.

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#31 ·
You've got to remember in the mid to late 70s they have been playing with ethanol mixed fuels. This isn't something that automotive manufacturers are suddenly dealing with. The fuel system in any modern vehicle sold in the us shouldn't have any issues with e10 blends. Not until higher % blends does it become an issue and require special pumps.

The amount of water collected by e10 will probably match what's mixed in gasoline tanks underground at the gas station. Many many stations have poor tank maintenance practices and leaks and water ingress is extremely common.

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