Pure Gas ( No Ethanol ) experiment

god "speed" with you

 

Good luck. I think there were others who tried it. I will look for the thread if I have time. That said, from a purely economic point of view, you would have to gain 33% better mpg with ethanol free gas in order to recoup what you have paid.

 

I'd be more than willing to pay 33% more for a single tank of gas, as an experiment to determine if there's a 5~10 percent benefit.

I got the bug when we filled the tank, a Chevron station up the coast in a small town. I'm not sure why, and I didn't look at the pump, other than to verify it was regular, but that was our walking-on-water for mpg tank. I suspect it was ethanol-free. From what I've read: there's certain quotas for ethanol addition that must be met, and smaller towns often "miss out".

 

In the U.S., its the renewable fuel standard: Renewable Fuel Standard (United States) - Wikipedia

The short answer is that refineries have to blend a certain volume of renewable fuels (19.92 billion gallons in 2019) into their fuel supplies, but they can do it however they like as long as they meet the volume requirement. That's why you can find places that still sell pure gasoline.

 

Any day of the week I can get pure gas by filling up with Chevron's (or Shell's) highest octane here. Probably a few others. I wonder if that muddies the waters though, is high octane by itself detrimental to mpg?? I have tried Chevron's highest octane once or twice, didn't notice any significant change. Ethanol-free regular is what I suspect I got, that up-the-coast time.

Another question rattling around: if the gas companies are relying on the ethanol addition to achieve the rated octane (ethanol supposedly raises octane), what happens if they omit adding it; is there a workaround?

 

Probably MTBE. That was one of the major additives used to increase the octane rating after leaded gas was banned.

 

And, methyl tertiary butyl ether MTBE is carcinogenic and highly water soluble. Leakage in underground pipes and tanks put MTBE into the water table. Methylcyclopentadienyl manganese tricarbonyl MMT is also used.
Octane Additives - Afton Chemical

Ethanol is the cheapest and least toxic product to raise octane and oxygenate gasoline. Oxygenation reduces carbon monoxide output.

 

Isn't the ICE designed to run on regular 87 octane? If you start running boosted octane will there not be a sacrifice on the back side?

 

+10% is reasonable expectation, but since gasoline is not sold on energy content basis, your mileage may vary (YMMV) from tank to tank.
>>Tell us what brands of gas you are using, for the control and E0 sample. Basically EPA gives some breaks to smaller companies. Also you are purchasing now in warmer weather where MPG Is better and gasoline has better MPG due to they take the butanes out as weather warms.

The basic purpose of an oil refinery is to raise octane (the raw gasoline in crude oil is probably 40 Octane or less), so they simply adjust the temperature on the platinum reformer to hit a higher octane spec. This increases the aromatics as needed to hit the octane spec, and it creates hydrogen as a by-product, which is used to remove sulfur from the diesel and gasoline.

MTBE is banned in USA as are metal octane boosters (MMT).

 

The only sacrifice should be to you wallet. Everything else is supposed to work just fine without any other sacrifices.

 

Plenty of octane boosters to choose from. Xylene and toluene are a couple. Part of the reason premium costs more is that the octane boosters tend to be valuable on their own.

 

...sure but xylene and toluene are normal components in gasoline, so that's what a refinery does if they need a higher octane, they just bump up the concentrations slightly as need to meet the octane. In the USA, the refinery will be limited to what EPA allows them to do, which is impacted by RFG recipe limits, etc.

 

Except for ethanol, everything in gasoline was in or made from petroleum. I didn't mean to imply that was otherwise.

 

1. Higher octane has no effect on mileage or performance on this engine. The engine is designed for 87 octane and I don't think the computer will advance timing or any of the other power-increasing methods in response to higher octane. The only sensor it has for octane (and it's indirect) is a knock sensor, if the Prime even has one. On a high performance engine designed for max power on 93 octane, if you run a lower octane the knock sensor will result in retarding the timing (I have measured the change on a Mazda MX-5).

2. If the energy content of ethanol is 66% that of gasoline, then a mix with 10% ethanol to 90% gasoline should produce a mix with 96.6% as much energy per gallon as pure gasoline. So, at best you should expect a 3.5% mileage increase on pure gasoline.

 

No. Higher octane fuel should have no effect on the performance of this engine.

 

Interesting experiment. Would like to see if any difference justifies the extra cost in pure gas.

 

What exactly leads you to believe that is possible ??

E0 contains about 3% more energy; therefore you should get about 3% better mileage, which is what most people report.......in a non-plugin gas engine or hybrid. Thus, on a strictly economic basis, if you pay more than 3% more for the E0, then it is not worth the money.

Doing this "experiment" with a plugin hybrid is pretty much useless........UNLESS you never plug it in.

 

My concern with ethanol gas in the Prime is it breaking apart since I rarely use the ICE. ive repaired enough lawn equipment and seen yellowish green sediment in the carbs. It lasts 1/2 as long as gasoline (pure).

It's a problem unique to PHEVs since most cars burn through gas fast enough. Last time I filled up, I only put 3 gal in and i have to force the car into HV mode so i can burn it in 3mos. I'm perfectly capable of using the EV mode >95% of the time. Next time i fill up, I'm going to only put in 2gal and pure gas. It lasts 6mo vs 3 from what I've been reading