91-octane PURE gas vs 93-octane 10% ethanol-blend

See if your car LIKES "Pure" Gas. Try it.

I know my F430 hated it (starting problems at 5250') whereas it loved 10% Eth.

(Mileage? - ROFLMAO)

 

That's good Jim, define "Pure" these days!

There you sit surrounded by corn fields Blampee.... the very place that brings us this rabbit piss fuel we now have mandated here and YOU are able to buy Pure Gas?! Here we sit at just under 6K elevation in Planet Boulder, where we dont have enough oxygen to burn even pure gas well and we get nothing but the alcohol swill grown in your area. Perfectly logical to some Govmnt folks I guess, that allows me to sleep better at night.

 

List of ethanol-free gas stations in the US:

http://pure-gas.org/index.jsp

 

And at least for Colorado, out of date. Ethanol free gas is not available at any service station in the Denver area.

 

Where I live SHELL (and a few others) has 91 octane ethanol free gas and HUSKY has 94 octane 10% ethanol gas........I didn't notice any difference (except for the premium price the supposed 94 octane is sold at).......and we're at 3,800' ASL........

There are more than a few threads here about the effects of long term use of ethanol blends though.........

 

recently I've had to go to the trouble of 'washing' this crap fuel blend to get ethanol free fuel, otherwise the two-stroke engines don't run. I'm soooo very tired of trying to get the old merc to run on this crap too, OK it's only a 20yr old car but seriously this ethanol is bad across the board and doubly so for older low compression motors.

and for those wondering, water is miscible with ethanol but not hydrocarbon chains, hence it's ability to 'wash' out the ethanol. with it's specific gravity greater as well it sits at the bottom in a denser layer, also since ethanol is hydroscopic it does this naturally in your tank. and on older not sealed so well tanks you're pumping a higher concentration of water/ethanol blended fuel at start up. sometimes it'll be worse and your pump will seize fuel lines will dissolve etc... entropy working overtime. all brought to you by big brother who knows better right?

 

there is a number of factors at play to answer that question correctly. For new engines in the last say oh 2-4yrs they have been designed to run optimally with ethanol, higher compression, ECU 'epa' programing, compatible materials etc..

for engines that were developed prior to ethanol fuels, not so much. although there is an increase in octane with ethanol it's flame front and burn rate speed is not advantageous with lower compression engines. there is a Gov payed for research paper that did just that, looked into the effect it would have on fleet vehicles. long long paper short, vehicles prior to 1995 were horribly effected in almost every single category. those post 1995 better tolerated higher concentrations of ethanol then the 10% available i.e. 20~30% was less damaging.

there are numerous 'shadetree' reports where the ethanol lowers MPG significantly and this in turn requires even more fuel to be used. I can say this is factual with my daily driver, I went from 26mpg to a horrid 18mpg due to this piss fuel. and here's an interesting point, removing the ethanol and running the lower octane resultant fuel improves the mpg to 24! and if I inject the ethanol/water into the intake stream it will improve performance better than blending it into the fuel.

 

It doesn't leave an aftertaste after you swish it around in your mouth.

 

If your car does not "ping" on 91 octane, then 93 octane brings you no benefits. {Independent of 93 pure gas and 91 pure gas.}

Alcohol slowly consumes ruber products (like thos found in <say> gas tanks, and fuel lines.) Dave Helms is working to address some of these issues.

Your engine makes optimal power on the lest octane that does not "ping" or detonate.

Modern engines have "ping" (i.e. knock) sensors and retard ignition timing and add fuel when knock is detected. Ferrari has stated that their cars run just fine (i.e. does not self destruct) as low as 89 octane, but does not make optimal power until 91 octane.

Just because the pump is laeled 93 does not mean the gas you get will be 93 (it could be 91.5 to 94.5) but will average 91 over long periods of time.

Making alcohol (i.e. fuel) from food is an idea that borders on an IQ = 1.22 (that is one point 22 or slightly less than 1 and a quarter, where normal is 100.)

 

10% ethanol has lots less energy. Go pure.

Another brilliant plan brought to you by lobbyists and special interest groups.
Rot.

 

Not shadetree reports, but simple chemistry - the heating value of ethanol-blend fuel is lower than the one of pure fuel. I have some exact measurements... somewhere...

 

I think E10 is about 118kish BTU vs the 125kish of gasoline.

 

Sounds about right. Ethanol has about 50% the energy of gasoline, so E10 has about 95% the energy content of pure gas.

Octane has nothing to so with energy content, just resistance to detonation. If you have a high compression engine, higher octane gasoline will let you run more ignition advance which generally results in more power. There are other factors involved such as quench and cylinder head design, but that is the basics.

 

Lot smarter guys than me have answered up above. The bottom line is in your DD it's probably fine to run the lowest grade of whatever it won't ping on. I had a Lincoln that needed 91+ or it would start to ping. My truck doesn't care as long as it burns so I use 87. Both mixed with ethanol here. In this area they didn't use to mix it but even out in the sticks "big brother" couldn't leave well enough alone.

For your 355 I'd run whatever the lowest grade that it won't ping on but NOT use ethanol if straight gas is readily available.

Your 355 is slightly older than your DD and even though you drive it often, it has the potential to sit for at least days on end without use. From what I'm hearing and reading the really bad part is when the E10 sits it starts separating and attracting water. Both not good things for parts like tanks and hoses.

Then again I'm no expert and I stayed at my own home last night not a Holiday Inn!!

 

From Hagerty's website:

http://www.hagerty.com/ethanol/faq.aspx

Here's a picture of my 2005 Crossfire SRT6:
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That's the real answer. Gas has higher energy content than ethanol so the answer appears straight forward. BUT, that assumes a constant engine operating condition. The 93 w/ethanol may produce more usable power IF you ran more advance to take advantage of the higher octane.

Then again, here in CA it all has ethanol so really doesn't matter.

 

Hopefully this list is up to date. I found a place not too far from me. I drove by tonight after they were closed and didn't see any stickers on the pumps. I'll give them a call Monday when they're open and see what they say.

 

But Dave, didn't Colorado also mandate MBTE or whatever the hell it is 20+ years ago?
Methyl-butol whatever the hell..

 

Methyl tertiary-butyl ether (MTBE), supposedly to make the fuel burn "cleaner". Yeah, whatever . . .

 

and Canada

I didn't realize that ESSO in all of Ontario (91 octane) is ethanol free...when I asked them, they told me it does contain ethanol

 

Yes!!! The station that's within about 20 miles of me is ethanol free! Guess where the 308 will be dining from now on??!!

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