Regular vs Premium Fuel: An Answer (Opinion?) To The Age Old Question

[steelblue5505]

I could not find a reference to Gasahol in post #23 which may have higher octane but lower energy to produce HP.
HKS

Hope this helps.

Gasohol is an alternative fuel consisting of a mixture of typically 90 percent gasoline with 10 percent water free ethanol. Gasohol can be used in most modern and light duty vehicles with an internal combustion.
The ethanol typically used in the Gasohol production is derived from fermenting agricultural crops. Fuel containing ethanol normally has an "E" number which explains the mixture. E10 consists of 10 percent ethanol and 90 percent gasoline whereas E85 is a blend of 85 percent ethanol and 15 percent gasoline. E5 and E7 are also common ethanol blends.

In terms of its octane rating, ethanol has a rating of 113. Fuels with a higher octane rating reduce engine knocking and perform better. Also, almost all gasoline in the US contains 10 percent ethanol. When you mix 10 percent 113 octane ethanol with 85 octane gasoline it increases the octane two points to the normal 87 octane most consumers use. So the higher the ethanol content, the higher the octane. The octane rating for E15 (15% ethanol) is 88 octane and E85 (85% ethanol) is 108 octane.

[TXBlueBird]

Okay, dumb question. I have read that the problem with gasohol, especially in hobby cars, is that water can sublimate out of the ethanol if the car sits for long periods. Mike’s post says the ethanol in gasohol is “water free.” Is this true and, if so, is ethanol undesirable for other reasons?

[HKS]

Okay, dumb question. I have read that the problem with gasohol, especially in hobby cars, is that water can sublimate out of the ethanol if the car sits for long periods. Mike’s post says the ethanol in gasohol is “water free.” Is this true and, if so, is ethanol undesirable for other reasons?

Other reasons. Lower Horsepower. Lower mileage, MPG.

Lately there is a big gripe about European cars misstating MPG.
I don't believe they waste corn to make gasohol over there. Pure gasoline gets better mileage.
About 14 years ago, I drove my Chrysler 300C to CA and Back. I always got 25MPG in Colorado and Utah.
On the way back to Nebraska I had gasohol and I got 22 MPG on every trip for 6 years, on a downgrade all the way to the wide Missouri.

HKS
P.S. Nowadays Colorado has gasohol also.

[007Cruiser]

I just checked on where you can get ethanol free fuel here in NJ. A few years ago the answer was no place. Today there are eleven stations. Six of those are airports and three are marinas. Can’t fill up there as they don’t collect the highway fuel tax. That leaves just two stations in the entire state. Neither is near me. Rusty can go to Downs Ford in Toms River.

You can look for ethanol free fuel here:

https://www.pure-gas.org/

[RustyFrye]

I just checked on where you can get ethanol free fuel here in NJ. ........Rusty can go to Downs Ford in Toms River.

I'd rather go to Mighty Joe's because they have this guy standing outside, but at $5.68 per gallon I'll pass...


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[steelblue5505]

Txbluebird,
Excellent question. All fuel will take on moisture as it sits over time. Fluctuating air temps causes that to happen. As gasoline & ethanol change temp water is formed, not huge amounts but still it is present & water thins almost dissolves out the ethanol separating it from the gas and the octane value goes down along with the quality of the gas & performance of the engine.

Ethanol is at its peak when it is at its freshest. Gasoline held in storage tanks waiting for transport to commercial outlets, gas stations, do not have ethanol in the blend. The mix is made up as the transport is prepared.