93 octane 10% ethanol vs 92 octane 0% ethanol

[masraum]

If you had your choice between 92 octane ethanol free gas or 93 octane w/10% ethanol, and you weren't worried about fuel lines/components, which would you choose and why?

The 92 will make more power, right?

But if your car calls for 93, how much are you in danger of retarded timing?

If the pump says 93 w/10%, is that 93 effective or has the 10% effectively knocked it back a bit more?

Just curious.

[Chocaholic]

Literally all modern fuel injected cars would do just fine on either. I’d probably go for for the non ethanol fuel more for political reasons than anything.

[berettafan]

Yep, **** the corn lobby.

[Bob Kontak]

Ethanol pops fast like low octane gasoline but it does pop good, increasing octane.

I would set aside conspiracy theories about how the big oil man is out to get you. If it says 93, it's 93, and will work fine and deliver more power under the right stress conditions than 92, no ethanol.

[cabmandone]

92 0 ethanol. Wish I could still buy 0 ethanol locally
If you're burnin through it, either one.

[red-beard]

The 92 Octane fuel without ethanol has more energy.

If it is truly dry, ethanol has 53,956 BTU/gallon while gasoline has 116,090 BTU/gallon. The 93 Octane has 109876.6 BTU/gallon. But all this will do is reduce your mileage by ~5%. The real problem is it attracts moisture, which means up to 10% water, which will make 98267.6 BTU/gallon, or almost 15% less mileage. Reality is it will be somewhere in between.

The 93 Octane fuel CAN produce more power IF the engine has higher compression and the timing is set properly. But between 92 & 93, it won't be much,

The other thing, that pure gas will probably be a LOT more expensive, since it is not made in the giant batches like the E10. So any mileage gain will be lost in the $/gallon. And any performance gain by the 93 Octane will be minimal.

Part of WW2 air war was won by 120 octane fuel

[cabmandone]

^^^
That's what burns me. 92 No ethanol fuel was only about ten cents more than 93 ethanol fuel around here until they pulled it. I used to put 92 no ethanol in my 911 at the last fuel up before storage and some Stabil.

[island911]

Originally Posted by red-beard

The 92 Octane fuel without ethanol has more energy.

If it is truly dry, ethanol has 53,956 BTU/gallon while gasoline has 116,090 BTU/gallon. The 93 Octane has 109876.6 BTU/gallon. But all this will do is reduce your mileage by ~5%. The real problem is it attracts moisture, which means up to 10% water, which will make 98267.6 BTU/gallon, or almost 15% less mileage. Reality is it will be somewhere in between.

The 93 Octane fuel CAN produce more power IF the engine has higher compression and the timing is set properly. But between 92 & 93, it won't be much,

The other thing, that pure gas will probably be a LOT more expensive, since it is not made in the giant batches like the E10. So any mileage gain will be lost in the $/gallon. And any performance gain by the 93 Octane will be minimal.

Part of WW2 air war was won by 120 octane fuel

THIS^

My 911 goes much further on a tank of 92 octane 0% ethanol than the typical. I was seeing ~10% better.

[Ctopher]

I would be less worried about 92 in a modern car and run it over the 93 for normal daily driver.

How about a twist on the OP question that I’m still undecided on here in south Texas. 93 with ethanol or 90 with 0 ethanol. We have a lot of QuickTrip stations popping up along with some Murphy’s with 87 -0%.

More specifically in my 87 Carrera and 2000 S2000, both cars are fun cars and don’t get driven but every couple of months. Shoot the S2000 went a whole year since it was last driven. Both cars get Stabil Marine fuel treatment but concerned with water buildup over time in the tanks. Concerned with lower octane in hot weather and driven hard when put to use.

So would you drop down to 90 octane with no ethanol for a non-daily driver old/modern car?


CTopher

[JackDidley]

Go ahead and hate on me but I like ethanol. Not E10 though. E85 burns sooo clean. Octane is very hgh. I do not think you can get spark knock with it. That makes it safe for high compression and spark advance. I used it for 3 years in my Corvette and only stopped due to lack of availability.

[red-beard]

That was one of the advantages of using MTBE. 5% MTBE hardly affected the BTU content of gasoline and it would not pickup water.

Around 2002-2003, in California my Jeep Cherokee would do around 15-16 mpg on the highway, with E10. With MTBE gas in Arizona, the mileage would jump to around 17 MPG. About 10-15%.

[cabmandone]

Originally Posted by JackDidley

Go ahead and hate on me but I like ethanol. Not E10 though. E85 burns sooo clean. Octane is very hgh. I do not think you can get spark knock with it. That makes it safe for high compression and spark advance. I used it for 3 years in my Corvette and only stopped due to lack of availability.

Not hatin on ya... just don't like the drastically reduced fuel mileage in my E85 F250. Don't mind saving the environment but DAMN... it gets expensive.

[red-beard]

Originally Posted by JackDidley

Go ahead and hate on me but I like ethanol. Not E10 though. E85 burns sooo clean. Octane is very hgh. I do not think you can get spark knock with it. That makes it safe for high compression and spark advance. I used it for 3 years in my Corvette and only stopped due to lack of availability.

For that application, as long as the mileage (~50%) isn't an issue and the car can take it, ethanol is a great fuel. 105 octane!

Remember, we were originally using ethanol as an Oxygenator, not to save the planet. MTBE was supposed to be poison (as is gasoline!). But we could have switched to ETBE instead which is far less poisonous, cheaper than ethanol, etc. But it was MTBE or Ethanol. MTBE lost the protection from lawsuits, so everyone switched to ethanol for oxygenation. Then the Renewable Fuel Standard came in. And that mandated 10% ethanol everywhere. And the corn farmers want 15%

[MAS956]

Originally Posted by cabmando

^^^
That's what burns me. 92 No ethanol fuel was only about ten cents more than 93 ethanol fuel around here until they pulled it. I used to put 92 no ethanol in my 911 at the last fuel up before storage and some Stabil.

Holy schiat! Granted I live in northern Kalifornia but I have only one source of ethanol·free gas near me: 95 octane is $9/gal and 100 octane is $11 per. I use the former in my generator and small engine applications. These prices were prior to the POTUS change. I've been afraid to go back since.

[petrolhead611]

Here in the UK we pay at least 7USD/Imperial gallon for. 95 octane, and nearly 8USD for 99 octane which some high performance cars demand.

[Fast Freddy 944]

Leave the ethynol in your car for a year....Ill take the 92 non-ethynol any day..

[Tobra]

Ethanol in your gas tank will never be dry, not ever

[JackDidley]

Originally Posted by Fast Freddy 944

Leave the ethynol in your car for a year....Ill take the 92 non-ethynol any day..

If you drive the car, water is not a problem. It sat for about 6 months when painting and it did cut out a few times when I first got back on the road. Not a big thing. Diving daily, no problem at all.

[masraum]

Originally Posted by Chocaholic

Literally all modern fuel injected cars would do just fine on either. I’d probably go for for the non ethanol fuel more for political reasons than anything.

Right, I figure a modern car that is running fuel system components that aren't affected by the ethanol, is going to be fine with either. I was assuming there'd be a few differences, but that it would ultimately come down to personal preference.

Originally Posted by berettafan

Yep, **** the corn lobby.

That's kind of what I was expecting.

Originally Posted by Bob Kontak

Ethanol pops fast like low octane gasoline but it does pop good, increasing octane.

I would set aside conspiracy theories about how the big oil man is out to get you. If it says 93, it's 93, and will work fine and deliver more power under the right stress conditions than 92, no ethanol.

I thought ethanol burned slow (hence the lower power output and the increased octane leading to less knocking) and was why folks use it on crazy turbos so they don't get knocking.

Originally Posted by red-beard

The 92 Octane fuel without ethanol has more energy.

If it is truly dry, ethanol has 53,956 BTU/gallon while gasoline has 116,090 BTU/gallon. The 93 Octane has 109876.6 BTU/gallon. But all this will do is reduce your mileage by ~5%. The real problem is it attracts moisture, which means up to 10% water, which will make 98267.6 BTU/gallon, or almost 15% less mileage. Reality is it will be somewhere in between.

The 93 Octane fuel CAN produce more power IF the engine has higher compression and the timing is set properly. But between 92 & 93, it won't be much,

The other thing, that pure gas will probably be a LOT more expensive, since it is not made in the giant batches like the E10. So any mileage gain will be lost in the $/gallon. And any performance gain by the 93 Octane will be minimal.

Part of WW2 air war was won by 120 octane fuel

Excellent point about the cost. I think the Katy Buc-ees has a 50 cent premium on their 92 ethanol free vs 93-10%.

Originally Posted by petrolhead611

Here in the UK we pay at least 7USD/Imperial gallon for. 95 octane, and nearly 8USD for 99 octane which some high performance cars demand.

I'm sure that you already know this, but the octane ratings are calculated differently in the UK vs the US. So what I can get here (premium) is 92 or 93, which would, I think be roughly equivalent to your 98 or 99. In the example in my original post, I think the last time I was at the gas station with the two different gases, the price was ~$2.75 for 93 w/10% ethanol and ~3.25 for 92 w/0% ethanol.

https://www.economist.com/babbage/2012/09/17/difference-engine-who-needs-premium

In the fuel test, the compression is raised until the engine begins to “knock”—ie, the fuel in the cylinder ceases to burn smoothly and instead detonates before it can be ignited by the spark plug. The cylinder pressure at which this occurs is then compared with that achieved while the engine is running on a reference fuel (a mixture of iso-octane and n-heptane). The ratio of the two pressures provides the RON of the fuel in question.

A better way of measuring a fuel’s ability to resist knocking under load is the so-called motor octane number (MON) test. This uses a similar test engine, but with a preheated fuel mixture, a higher engine speed and variable ignition timing. Because it uses more real-world conditions, the MON rating is typically eight to ten points lower than the equivalent RON figure.

In Europe, the octane rating on the pump is simply the RON figure. America, by contrast, uses the average of the RON and the MON figures, called the AKI (anti-knock index). Thus, 97 octane “super unleaded” in Britain is roughly equivalent to 91 octane premium in the United States.

[wdfifteen]

Originally Posted by Ctopher

So would you drop down to 90 octane with no ethanol for a non-daily driver old/modern car?
CTopher

My '47 Dodge truck and my '56 Porsche coupe get 90 octane 0% ethanol. The cam/compression in the Speedster won't allow 90 octane. The last time I had it down I added a couple of shims to lower the compression, but not enough. My 93 is tuned for 93 octane, so both the Speedster and the 911 get 93 octane w/ethanol.