Use of E0 Non ethanol gas in 2023 Prius Prime

AKA straight gas? The one time I for sure tried it was Chevron's highest octane up here (94), didn't really notice any difference. That's the only way you can get it here, officially. Maybe 87 octane straight gas would be a different story:

One time we did gas up in a small town with regular (87 octane) and got stellar mpg for that tank. Not sure why, but suspected it was straight gas, no ethanol.

 

Yes. I guess with a Prime it'll be harder to tell, but would be interesting to hear your impressions, what it does for mpg in particular.

 

E0 should be good for all unleaded gasoline engines, and is what much of the world still uses, absent U.S. tax credits and energy and agricultural policies. It should also average 3.3% better MPG. Same price is very surprising, it is usually priced high enough to not be worth the MPG difference.

For many small engines in seasonal yard and sports equipment, yes. For regular cars with modern evaporative emissions controls, and operated all year without seasonal storage, much less so. For PHEVs (plug-in hybrids), much much less so, as they are designed with much better sealing of gas tanks than other cars, to keep the fuel good for a year:

How designing the Chevy Volt's sealed gas tank brought automakers, CARB together

Plenty, though I am not among them.

 

I run E0, no problems. My driving patterns aren't consistent enough to quantify any MPG gains. I'm doing it mostly to simplify my life and prolong my car's life to the max.

Simplify, because I can use the same fuel in my car as in my handful of small gas-powered equipment(which needs E0). And I also don't have to worry if I don't drive much and the fuel sits in the car for a month or more.

Prolong, because E0 is theoretically a tiny(emphasize - tiny) bit better for the car. Likely won't see any benefit until 15-20 years or 300k+ miles.

Even though I'm running E0(because it's easy and convenient for me to get), I'll be the very first in line to say it's not really worth it. Of course if there's no price difference in your region...

OTOH, oxygenated fuels, like ethanol blends, are cleaner and better for the environment, so they have that going for them. However, growing, harvesting, transporting, and processing ethanol source materials use fossil fuels as well, so it's hard to say how much they're a net positive. I'm sure the info is out there somewhere, but I bet there are dozens of studies showing significantly different results depending on who paid for the study(and what parameters they used to set it up).

 

There are a couple stations around here that sell the undiluted stuff. It's about a $1 more per gallon at this time. Since I only needed to fill my Gen 3 about once a month, The difference back then wasn't so much so I figured what the hell.

After a couple months, when the fall turned to winter, I changed my mind on that one.

When it's more to fill up the tanks on all those pickups and SUVs around here, people won't spend the extra money. Especially when they're paying that much to begin with. That means the undiluted gasoline sits there in the tank until some unsuspecting nut in a Prius fills up.

That means the gas in the station's tanks sits there - separating, perhaps there's a way for water to get into the tank, or if the seasons change and the tank still has the summer gas but it's winter...

The car started running like crap until I filled up with the same gasoline everyone else was using.

Maybe if I still had a gasoline lawn mower, I'd get a gallon or two of that stuff. Otherwise, stick to the stuff everyone else is buying.

 

It will be slightly better fuel economy with E0 gasoline due to its higher specific energy, but if it is a lot more expensive, it is not worth it.

 

E0 is OK for the Prime, and if nothing else there will be a placebo benefit - especially if the price is the same.
Here, there's a $0.50/gal price delta for E0 locally - so I'll keep using E10

 

Again, slightly better fuel economy with it due to higher specific energy but not worth if it is significantly more expensive.

To be specific, you will get a 3.3%-better fuel economy with E0 than with E10. So, it is like 60 mpg with E0 vs. 58 mpg with E10.

Likewise, you will get a 5.0%-better fuel economy with E0 than with E15. So, it is like 60 mpg with E0 vs. 57 mpg with E15.

 

^ Never noticed that in 200,000 miles in G3's but that ground has already been well plowed.

The question was whether or not it is OK to use E0 in a G5 Prime.
Actually, the G5 has a fairly decent sized battery 13kw which for many drivers means that they won't need to burn as much gas.

 

recently discussed at length here:
Best brand of gasoline? | PriusChat

 

TL;DR?

This was discussed ad-nauseous back when the G3's were the newest hotness - but that was something like 15 years ago.
I acknowledge that ICE have changed drastically since then as have gasoline formulae, so color me 'sorta-interested.'

The ONE (and only) benefit to an EPA guestimate for fuel efficiency is the same as that for a manufacturer's MSRP.
They may be 'made-up numbers' but they're the SAME made up numbers for each and every vehicle.

ACTUAL mileage, as they say....WILL vary.

 

The aromatic compounds used in E0 to increase octane can lead to more carbon deposits. The paper I saw about that was from 1991, so maybe things have changed in the formulation.

 

If you aren't turning over the gas in your tank every 3 months, and want E0 because of a longer shelf life, not sure the gas quality would be my primary concern. Is that good for the long-term life of the ICE? My concern is it's a usage pattern that may be pretty far outside what the car was designed for.

 

Good point about octane.

However, I thought aromatics tended to have a higher solvency and clean more.

Moreover, according to that logic, premium (high-octane) gas would lead to more deposits, which is probably not true. In fact, some gas companies market their premium gas as having the most cleaning power.

 

Some are sold separately has solvent cleaners, but things change when they start burning. These compounds leave more carbon residue behind after burning. Higher amounts lead to more deposits.

Ethanol itself is an octane booster, and some refineries used it as such before the ethanol mandate. The increased carbon deposits in E0 is fuel without other oxygenates. Those compounds reduce particles, which are carbon deposits that just didn't end up sticking to something. So this carbon issue wasn't a problem in the old days with MTBE.

The marketing about about cleaning power refers to the level of detergents in the gas. Some add more to their premium fuel. To qualify as a Top Tier brand, the regular octane has to meet that standard's minimum, and adding more to that has little extra benefit.

 

The problem is that you are speculating without knowing the true composition of gasoline, let alone a true understanding of how deposits are correlated with the composition.

According to Sunoco, higher-octane gas simply has higher overall quality:

87 octane fuels tend to be less refined and contain more unstable hydrocarbons. As the months pass during storage these unstable components react to form gums, varnishes and lower octane hydrocarbons. As a result the octane can decrease within months for 87 octane fuels, especially when stored under less than ideal conditions. 93 octane fuels are more refined and contain more stable hydrocarbons. These stable hydrocarbons can last 2-3 times longer than 87 octane fuel. Even in proper storage 87 octane gas can start to degrade in 3 months, 93 octane fuel should last closer to 9 months before degradation is noticeable. Keep in mind that 93 octane fuels are still susceptible to octane loss and vapor pressure decreases due to butane evaporation.

Octane stability: High-octane vs. low-octane fuels—Petroleum Service Company

So, if E0 is made using higher-octane gas, it would negate the effects of not having ethanol.

That said, I am not ever bothered by this. I simply go to the same Chevron station every time and pump the 87-octane E10 (?) fuel. I once used the Mobil's Synergy Supreme+™ 91-octane gas and didn't notice the slightest difference other than the price.

Last but not least, here is the list of the TOP TIER™ stations. Always go to a TOP TIER™ station.

Fuel Stations—TOP TIER™

In the US, they are:

• 76
• Aloha
• ARCO
• Beacon
• Belmont Car Wash
• Cenex
• Chevron
• CITGO
• Conoco
• Costco Wholesale
• CountryMark
• Dash In
• Diamond Shamrock
• Express Mart - Wisconsin
• Exxon
• Fast Fuel
• Gold Medal Gasoline
• Harmons Fuel Stop
• Hele
• HFN - Hawaii Fueling Network
• J&E Wendy
• Kirkland Signature Gasoline
• Marathon
• Mega Saver
• Meijer
• Meijer Express
• Mobil
• Ohana Fuels
• Phillips 66
• QT
• QuikTrip
• Ranger
• Ranger Fuel
• Ranger Mustang
• Ranger Stallion
• Ranger Thoroughbred
• Reeders
• Road Ranger
• Rutter's
• Shamrock
• Shell
• Shell Nitrogen Enriched
• Shell V-Power
• Shell V-Power NiTRO+
• Simonson Station Stores
• Sinclair
• Sunoco
• Texaco
• True Turbo
• Tulalip Market
• Valero
• Value America
• Waterway Fuels
• Win Win
• WOW

 

First, Sunoco has a vested interest in getting people to buy the higher margin fuel.
Second, that statement is about gasoline in storage, not its ability to prevent deposits in engines and fuel systems.

Gasoline degrades through oxidation and evaporation. One of the effects of that degradation is the drop in octane. One of the stated reasons for the gen1 Volt to use premium was being cautious of that possibility. So if you are looking to store gasoline in a plastic jerry can for a year or more, yes, get the higher octane. Turns out a car fuel tank is a much better storage device than a jerry can, and most cars aren't parked for 9 months.

If you storing the gas for extended periods, you want to avoid ethanol blends. It, and the water with it, are bringing oxygen into the mix.

Ads about premium being a better cleaner of deposits are talking about the detergents. Maybe they do have more or better. maybe they are just leaving that impression. To qualify for the Top Tier label, all the octanes the brand sells have to meet the standard. Perhaps having more in premium does an even better job. I'm not finding evidence that someone actually does add more to their premium though.