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Using Ethanol Free Gas = VROOM!

DanW

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The ethanol free gasoline produces slightly (very slightly) more power and efficiency because ethanol has fewer BTUs than gasoline. The octane is the same, whether it has ethanol, or not. 87 is 87. The higher octane is more resistant to pre-ignition, or knock. lower octane is less so. Some engines, like the Jeep 2.0 turbo, will advance the timing with higher octane fuel and will give you a slight horsepower and efficiency boost. Most engines won't take advantage of it, though. I had a 2006 Solstice 2.4 that produced probably 5 to 10 more horsepower on 91 than it did on 87. I don't really think I could feel it, but it did get slightly better mileage.

As for ethanol, any engine will have a horsepower advantage with less or no ethanol. I can't tell a difference in my 3.6 in ethanol free, or with higher octane, but my old 3.8 JK simply runs better on higher octane and ethanol free. It gets about 1/2 mpg better on 91 ethanol free and is very slightly smoother with no knock. I'm not sure it actually gains enough power to feel it, but the fact it runs smoother makes it feel quicker. Every engine is different, though, so your mileage may vary, literally.
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Al13

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I filled up the JLR with top tier ethanol free 87 octane gas. There is a noticeable increase in power. I can't say anything about improved MPG, because my driving habits are so variable, it's tough to make a good comparison without effort. And price wise, it was maybe ten cents more a gallon than a nearby corporate gas station (Chevron). I'll need to pay attention to the temp gauges, because it may run 5'ish degrees F hotter.

FYI- first time I've used ethanol free gas.

FYI I use Pure Gas Org (free iphone app). It's really well done.
I use it in my Harley unless I am out of the area and unable to get it.
 

stil2low

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I’m curious to see the difference in the JL being already way better on fuel than my JK
I’m in a boarder town and we have non ethanol fuel in most of our pumps but when we go state side to wheel I can definitely see the drop in mileage using e10. Usually dropped my mileage by about 4 mpg on the JK
 

ALRUI

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My wife filled up the other day with the ethanol free & immediately noticed improved gas mileage & slight power increase. Were getting scammed at the pump every time we fill up thanks to greedy politicians and ill informed environmentalists folks. Ethanol is a scam all around and it isnt good for older vehicles or equipment either!
 

UKCATS

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GM did a study several years ago, comparing regular gas vs E85. They reported a 18% loss in efficiency with E85. I read in a car mag. I’ll see if I can find it.

EDIT: Hmm, at first glance looks like 25% less MPG. That is not a minimal loss.

“E85 fueled MPG and range are lower than gasoline by about 25% • Slightly better than fuel
Δ energy (for normally aspirated S.I”

https://biomassboard.gov/pdfs/jones...ve_fuel_ethanol_in_the_us_gm_experiencekw.pdf
 

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DesmoDog

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Sorry about that, point is the same, gas ignites (or blows up, catches fire, detonates) before it is supposed to causing your rod to exit the side of your block. You want to correct me on my bad terminology there too?
Well since you asked... ;-)

Actually you didn't say all of this so consider this a community post, not one aimed at you directly.

Pre-ignition is not the same as detonation/knock. Pre-ignition means a hot spot ignites the mix before the plug fires. This can lead to detonation but it doesn't HAVE to. Either one can happen without the other. The thing is, if you get pre-ignition but no knock, you'd never know it pre-ignited. And that slight knock you get towing a trailer up a grade in August is not caused by pre-ignition.

Normal combustion - Plug fires, air/gas mixture ignites and then burns because of the flame front(s). This takes time, and as it's happening, the unburned part of the mix is exposed to higher temps and pressures. With normal combustion the pressure in the cylinder ramps up relatively smoothly. Google "indicator diagram" and it'll show pressure/volume curves for normal use. No sharp peaks, no shock waves, no explosions.

At high temps and pressures, the mixture will eventually auto-ignite/detonate/knock. There is a limited amount of time the mix can withstand a given high temp and pressure before it goes BOOM. No flame front, it just explodes. This is not normal combustion. The trick is to burn the mix before this happens. MSD ignitions, dual plugs, swirl in the intake, it's all there to burn the mix faster.* When the mix detontes, the pressure doesn' tramp up. It's a shock wave. In fact it's the shock wave that gives "knock" it's sound and name. The sound is caused by the shock wave crashing around in the cylinder. Indicator diagrams of cylinders that are knocking will show spikes.

Anywhos like I was saying, detonation happens when the mix is exposed to high temp and pressure for too long. Higher octane gasoline can resist auto-ignition from high temp and pressure longer than lower octane gasoline. That's all the octane rating indicates.

To sum it up, pre-ignition happens before the plug fires. It can lead to detonation but is not required to get detonation. Detonation happens after the plug fires. There are high speed photos/slow motion films that clearly show this.

*Not to derail the thread further but this hints at debunking the wive's tale that high octane gasoline burns slower to control knock. No it doesn't, and if it did burn slower the tendancy to knock would get worse, not better. Don't take my word for it, Google what fuel companies (NOT Hot Rod Magazine or your buddy's uncle's ex-wife who's dad worked at a gas station in the '50s) have to say about octane rating vs flame speed in pump gas.
 
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1quick1

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I drove through somewhere in the Midwest, maybe Iowa or Indiana and they had 87 ethanol free and it was like $.40 more. I tried it but honestly didn't notice a difference.
 

Ronnie S

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I drove through somewhere in the Midwest, maybe Iowa or Indiana and they had 87 ethanol free and it was like $.40 more. I tried it but honestly didn't notice a difference.
We got a couple stations here that have ethanol free in Brighton Michigan (Shell and Sunoco). I might try it and see if I notice a difference.
 

higbyz

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I pay $3.09 for 91octane non ethanol Mobil gas (93 0ctane W/ ethanol is $3.19.) I use it in my bike, Allroad , and 4cyl 2018 JLU. It definitely improves mileage . Not sure I notice a power difference because I have been using it for so long . My Harley is 14 years old, I love feedin it the good stuff !
 
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jbozz

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That may be the case, but recall the specs say don’t put fuel with ethanol beyond e85. So I would not interpret that the motor is tuned to e85. I’ve never actually seen e85. In Washington state the upper limit is e90. I will say categorically, you can notice more power with e100 (ie ethanol free, top tier). And laws of physics (Newtonian and conservation) say more power for same unit of fuel equals more mpg.
you are correct. the owners manual says DO NOT use
DO NOT use E-85, gasoline containing methanol, or
gasoline containing more than 15% ethanol (E-15). Use of
these blends may result in starting and drivability
problems, damage critical fuel system components, cause
emissions to exceed the applicable standard, and/or cause
the Malfunction Indicator Light to illuminate. Please
observe pump labels as they should clearly communicate
if a fuel contains greater than 15% ethanol (E-15).
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