Ethanol vs Non-ethanol

[Veraciousreasoning]

So I noticed a couple gas stations that have non-ethanol gas. I remember vaguely reading something about it here on the forums but don't remember where. IS there a stark difference in the types of gas and what kind of gas is best for a 1980 datsun ?

[datzenmike]

Ethanol has less energy so it will dilute ordinary gas making it weaker. So if I had the choice and resources I would run it instead. Otherwise there's nothing wrong with 10% blend, been running it for decades.

[thisismatt]

Ethenol absorbs more water and can damage rubber & plastic. If you daily drive it I wouldn't worry about it, but if you store it for weeks/months on end you might consider the ethenol-free gas, or use a fuel stabilizer

[wayno]

That ethanol gas eats metal, they had to change out all the metal tanks in gas stations to plastic tanks in the entire country as the metal tanks would rust and get holes in them, it does the same thing to our metal Datsun tanks if it sits in the tanks for long periods of time, new vehicles have plastic tanks.

 

As mentioned, if you daily/weekly drive your Datsun and constantly put fresh gas(crap fuel) in it you should be alright.

 

Even the new gas lawn mowers/blowers/rototillers/ect. have had plastic tanks for years now, if your going to let that crap sit in your metal tank you should use a tank liner in your tank or buy ethanol free gas.

[7twentyguy]

Since we’re on the subject of gas,

what octane is everyone burning? I know price dictates what we buy, but if you could run whichever octane you wanted which would you use.

when I bought my 720 the PO said it runs better on high test than regular, but my neighbor says never use premium because it will shorten the life of the motor.

what do you think?

[thisismatt]

16 minutes ago, 7twentyguy said:

Since we’re on the subject of gas,

what octane is everyone burning? I know price dictates what we buy, but if you could run whichever octane you wanted which would you use.

when I bought my 720 the PO said it runs better on high test than regular, but my neighbor says never use premium because it will shorten the life of the motor.

what do you think?

 

I would no longer take advice from your PO or neighbor 😂

 

Use the lowest rated that doesn't cause detonation/pinging/knocking. For most regular Datsuns that would be the cheapest option at the pump. If you have a higher compression engine you may need higher octane to prevent pinging. If you have a modern vehicle that suggests a certain octane, the efi/timing system will adjust accordingly if you use lower than recommended and it won't necessarily put out rated power but it will still operate fine.

[datzenmike]

5 hours ago, wayno said:

That ethanol gas eats metal, they had to change out all the metal tanks in gas stations to plastic tanks in the entire country as the metal tanks would rust and get holes in them, it does the same thing to our metal Datsun tanks if it sits in the tanks for long periods of time, new vehicles have plastic tanks.

 

As mentioned, if you daily/weekly drive your Datsun and constantly put fresh gas(crap fuel) in it you should be alright.

 

Even the new gas lawn mowers/blowers/rototillers/ect. have had plastic tanks for years now, if your going to let that crap sit in your metal tank you should use a tank liner in your tank or buy ethanol free gas.

 

Lots of stuff is plastic now. Lighter, cheaper to make and survive accidents better than metal. Metal ground tanks will always eventually corrode and leak and 50 years ago it was simply the cost of doing business but since then we are more environmentally aware and the cleanup and constant monitoring or regular replacement is prohibitive. 'Plastic' tanks avoid this whether gas or E80. 

 

27 minutes ago, 7twentyguy said:

Since we’re on the subject of gas,

what octane is everyone burning? I know price dictates what we buy, but if you could run whichever octane you wanted which would you use.

when I bought my 720 the PO said it runs better on high test than regular, but my neighbor says never use premium because it will shorten the life of the motor.

what do you think?

 

Octane is simply a measure of resistance to self ignition (pinging) usually caused by heat of compression. Simply put your compression basically determines what octane level you use. Higher compression = higher octane. All Datsuns are around 8.5 compression and should run on 87 octane. Possibly in the summer heat in some areas a higher 89 may be needed. Higher octane does not confer extra power, but it can allow you to run closer to the ideal timing on a higher compression engine and extract more power more efficiently from the same gas with lower octane. 

 

If you run higher octane than needed you are simply buying more expensive gas. Try a few tank fulls of high octane and keep rigorous track of amounts and distance. Compare to regular gas. They will give the same mileage. 

 

If the previous owner thought it ran better it's because of the placebo effect. When you know you paid more for it and expect it to perform better, bias creeps in and you subconsciously alter your driving habits.

[KELMO]

I'll chime in as well.

I have access to 100LL AV gas, so, 100 octane. It ages better than pump gas or so I've been told. I have used it in my small engine stuff (lawnmower, chainsaw, etc.). If any of the Datsuns are to sit for very long I always put about 4 gallons in the tank. Other than that, I will typically run a tank of pump gas and then a tank of AV fuel. I have also been told that AV fuel burns hotter. That being said, I do not run it in anything that has a catalytic converter as it will melt the inside of it.

The one major drawback is the price per gallon which in these parts is between $5.05 to $5.85 and the price (just like pump gas) is on a rapid rise.

[datzenmike]

Hotter? AV probably had no ethanol in it and as mentioned alcohol contains less energy than regular gasoline. It dilutes it's power, watering it down. By comparison AV will make more power so will produce more waste heat.

 

I don't think aviation engines are much higher compression than car engines but detonation MUST be avoided at all costs in an airplane where you can't just pull over where ever you like.

[Duncan]

List of US and Canada Ethanol Free gas stations.

 

  https://www.pure-gas.org/

[john510]

1 hour ago, 7twentyguy said:

Since we’re on the subject of gas,

what octane is everyone burning? I know price dictates what we buy, but if you could run whichever octane you wanted which would you use.

when I bought my 720 the PO said it runs better on high test than regular, but my neighbor says never use premium because it will shorten the life of the motor.

what do you think?

I'd say your neighbor is a moron.

[john510]

1 hour ago, datzenmike said:

 

Lots of stuff is plastic now. Lighter, cheaper to make and survive accidents better than metal. Metal ground tanks will always eventually corrode and leak and 50 years ago it was simply the cost of doing business but since then we are more environmentally aware and the cleanup and constant monitoring or regular replacement is prohibitive. 'Plastic' tanks avoid this whether gas or E80. 

 

 

Octane is simply a measure of resistance to self ignition (pinging) usually caused by heat of compression. Simply put your compression basically determines what octane level you use. Higher compression = higher octane. All Datsuns are around 8.5 compression and should run on 87 octane. Possibly in the summer heat in some areas a higher 89 may be needed. Higher octane does not confer extra power, but it can allow you to run closer to the ideal timing on a higher compression engine and extract more power more efficiently from the same gas with lower octane. 

 

If you run higher octane than needed you are simply buying more expensive gas. Try a few tank fulls of high octane and keep rigorous track of amounts and distance. Compare to regular gas. They will give the same mileage. 

 

If the previous owner thought it ran better it's because of the placebo effect. When you know you paid more for it and expect it to perform better, bias creeps in and you subconsciously alter your driving habits.

My high mileage Toyota Tacoma gets at least 1 mpg better on 91 octane than 87 octane.If it's mostly freeway miles it's nearly 2 mpg better.

[datzenmike]

Because EFI and the timing can be optimized with knock sensor feedback. The compression is also probably higher. We had a '07 Ford van with 4.9 L IL six. We were traveling 60 miles a day for a few months so I ran several tanks of premium and the extra mileage actually paid for the cost difference and a bit more. It seemed strange to be paying so much extra for a fill up but the mileage didn't lie.

[Thomas Perkins]

11 hours ago, 7twentyguy said:

Since we’re on the subject of gas,

what octane is everyone burning? I know price dictates what we buy, but if you could run whichever octane you wanted which would you use.

when I bought my 720 the PO said it runs better on high test than regular, but my neighbor says never use premium because it will shorten the life of the motor.

what do you think?.Don't listen to your neighbor.I have been using 93 octane in my 85 Z-24 since 2009,since I had the Jasper engine installed and have over 95,000 miles on it.The kicker is to keep your carb. tuned,I have a Weber and my plugs stay looking new and it runs better on the Premium gas but is costly.

 

Tommy you have to put your reply outside the quote 'bubble'. Like mine

[paradime]

Bare in mind, as automobile fuel ethanol/gasoline blending has been around for over 100 years. Hell the Ford Model T was a flex-fuel vehicle. In 1919 it was Prohibition that handed the entire internal combustion fuel market to Rockefeller. No surprise, but John D. was a huge proponent of the 18th Amendment.

 

https://www.eia.gov/energyexplained/biofuels/ethanol.php

 

 

 

 

 

[datzenmike]

In the '40s my dad drove a tractor that you start on gasoline then switch to alcohol.

[Dguy210]

I run all 93 ethanol free on the A14 in my B210. Definitely more power, not sure on mileage though. Compression is probably a bit higher than stock.

 

What sold me is that it was a difference in which gear I was using to go up certain hills between 87 unleaded an 93 ethanol free. Of course it is also very easy for me to run as the rural gas station just down the street from me sells it for all the small engine and classic cars out here.

[paradime]

Hey Dguy, with your mild 8.5:1 static air/fuel/ignition A14, it's kind of an unfair fight to pit 93 octane full gas against unleaded 87 octane E10 gas. LOL

 

Sounds counter intuitive but under higher compression, ethanol has a relative octane of 107, burns 20% cooler, resists detention better, and makes more power than 110 octane race gas. Naturally aspirated drag racers are running 16:1 compression on full ethanol.

 

I did a bunch of research on ethanol when I was building my 510. Here's a link to a thread on this from a few years back.

 

[datzenmike]

That's the thing, the engine has to be purpose built with insane compression to extract all the benefits of E85.