Mid Grade Or Premium Gas

[JohnWedell]

I’m towing at the max combined weight (25,000 lbs.). It is a gasser and do not want a diesel. I use mid grade gas when towing and regular around town. I tow from New York to Florida in November and back to New York in March only. Does anyone use premium when towing.

[LukeDagny]

I've never noticed an increase in fuel economy running higher octane than what's called for. I like to use name brand fuel, like Shell, Exxon, Texaco. etc. vs no name cheap fuels.

I've read some have experienced better fuel economy when running non-ethanol as opposed to the typical 10% ethanol most stations are selling.

I should also mention that I usually drive the speed limit or slightly more.

[Kevin Cooper]

In the old days, it made a difference. Sometimes pulling hard the engine would get a little knock in her. With the new engines having the sensors and computer adjustments, it’s not going to make much if any difference. Octane levels are so the fuel doesn’t try to ignite early in higher compression gas engines.
I like to run no alcohol gas once in a while. It gets better mileage, and the generator really runs better.

[ARoamer]

I had a gm 6.2 that reccomended premium, I could tell a slight difference in power if I wasn't.
Yes, any ethanol blend will reduce mileage.
A local Citgo station buys it's fuel from the wholesaler that gives them the best price. I don't know if the major name brands do also, but I'd think they do.

[CAG]

What does your vehicle call for in the manual? Today's vehicles are computer controlled and if it calls for premium (my wife's Audi) and you mess up like me and put standard in it, the computer sets the system for that and moves on. It likely will not perform at the high standards as with premium but it won't damage the engine and you might make a gallon or two less fuel mileage. But if it calls for low grade and you put premium in it, it will NOT change the computer and make it run better or give you better mileage.


Bottom line, don't waste your money on octane that is not called for. It is just that. A waste of money.

[LukeDagny]

A local Citgo station buys it's fuel from the wholesaler that gives them the best price. I don't know if the major name brands do also, but I'd think they do.

I was told by a wholesaler that they might sell gas to different name brand retailers. The difference is in the additive package that's added when delivered.

[CAG]

Originally Posted by LukeDagny

I was told by a wholesaler that they might sell gas to different name brand retailers. The difference is in the additive package that's added when delivered.

I don't think that changes the octane.

[Kevin Cooper]

Originally Posted by ARoamer

I had a gm 6.2 that reccomended premium, I could tell a slight difference in power if I wasn't.
Yes, any ethanol blend will reduce mileage.
A local Citgo station buys it's fuel from the wholesaler that gives them the best price. I don't know if the major name brands do also, but I'd think they do.

That is a higher compression engine. So premium fuel.

[LukeDagny]

Originally Posted by CAG

I don't think that changes the octane.

You are correct. I wasn't clear. My understanding from the wholesaler was the additive package was the difference between top tier or bottom tier gasoline.

[craigav]

Originally Posted by LukeDagny

You are correct. I wasn't clear. My understanding from the wholesaler was the additive package was the difference between top tier or bottom tier gasoline.

I have read, and perhaps you have more information, that there is more additive added to the premium fuel than there is added to the regular grade. Perhaps people believe (for vehicles that don't need the higher octane) that the reason their vehicle runs better on premium is because of the higher octane rating but instead it is because of the additional additive added to the premium grade.

Chevron is one example with their "Techron" additive, however that additive (if it is the same) can be purchased at many auto parts stores. I say many, I have only seen it at NAPA stores but haven't really looked for it, just that I saw it sold there. ~CA

[LukeDagny]

I have read, and perhaps you have more information, that there is more additive added to the premium fuel than there is added to the regular grade. Perhaps people believe (for vehicles that don't need the higher octane) that the reason their vehicle runs better on premium is because of the higher octane rating but instead it is because of the additional additive added to the premium grade.

Chevron is one example with their "Techron" additive, however that additive (if it is the same) can be purchased at many auto parts stores. I say many, I have only seen it at NAPA stores but haven't really looked for it, just that I saw it sold there. ~CA

I don't know that much, but it seems reasonable that higher octane has more additives.

One of the things that Techron does is preserve gasoline's octane rating. Ethanol gas has a short shelf life, and I used Techron when my daughter put her car in storage for two years. The battery was flat, and needed a jump, but the car started right up and ran great.

[Kevin Cooper]

A quick Google and this popped up top of the list. I have heard for years that higher octane gasoline has higher amount of detergent in it. My old lawn mowers carbs. Would clog up with regular gunk. Never did on premimum gasoline though.
But this what some else says.

No matter what you've heard, premium-grade gasoline won't do more to clean deposits from your fuel injectors or other parts of the fuel system because today's regular gas contains the same detergent additives. The main difference with premium is its octane rating — 91 or higher compared with 87 for regular octane.Apr 6, 2016

[craigav]

I thought I would check (search) for details for a name brand fuel and Shell says their Premium has more cleaning agents (additives) than their other fuel grades:
~CA

(also to note, I didn't check other brands, Shell popped up first in my search. I suspect other brands and in particular low-cost gas stations would be different)

What makes Shell V-Power® NiTRO+ Premium Gasoline different than other Shell fuel grades?
Shell V-Power® NiTRO+ Premium Gasoline contains the highest concentration of our proprietary additive that removes up to 100% of performance robbing deposits. In fact, Shell V-Power® NiTRO+ contains six times the amount of cleaning agents required by federal standards.

https://www.shell.us/motorist/shell-...line-faqs.html

[JFlightRisk]

There's a statement in my 2016 manual for fuel that states:

"For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer."

I will either get 93 octane from Kwik Fill, or 90 non-ethanol from Sunoco around here for the turbos.

[TCNashville]

The owners manual for my '17 F-250 with the 6.2L recommends to use 90 octane when towing. I pretty much know well in advance when I'm able to go camping so I make sure I have half a tank or less of 87, then go fill it with 93 to achieve the 90 rating. I have towed before with mostly 87 and can't tell the difference between that and the 90 but it makes me feel better.

[PaulB12]

Bobby Likes, car guru, always said use the octane that the manuals call for.
Higher compression engines required higher octane.
But what do I know, I drive a diesel.
PaulB12

[CAG]

Yeah, it is pretty much what floats your boat but buying a RV, coming here and asking about gas mileage, and then asking what octane to use, well, just drive it, put what octane it calls for and if you are worrying about gas mileage, you are in the wrong vacation endeavor. If you like 93, go for it! I spend money on a lot of junk that I don't need but like to have.

[TaftCoach]

I log every fill up. Twice I've had uncharacteristic low mpg between tanks while towing. Like 6 instead of 9. Both are stations I was unfamiliar with. But that's out of dozens, perhaps hundreds of other fills at similar stations. I do notice a slight increase with mid range which breaks it about break even on cost so I generally use that while towing.

[JFlightRisk]

I keep a log for both vehicles also. A good way to notice if something changes on the engines or trannys. As long as I see 10 or 11 mpg towing, and 99 mpg not towing, I'm happy!

[Russc25]

TLDR: top tier gas. octane that the owners manual calls for, no more.


Octane and additives are two different things

Octane is the fuel's resistance to preignition aka knock. Higher temps, high compression, high load/low speed all lead to knock. scoping the conversation to modern computer controlled engines, check the owners manual. The engine's designed and the computer's programmed with a certain fuel in mind. Manufacturers spend thousands of hours developing the engine on that fuel in various conditions. The computer's designed to de-rate by pulling back ignition timing if it detects knock to prevent engine damage but it doesn't have unlimited authority, you can still blow an engine that way. running lower-than-spec octane fuel is one way to cause knock.

On the other hand, if there's no knock, the computer will only run the programmed spark advance table, it won't advance until it sees knock. That means if the computer isn't programmed for higher octane, you won't get any benefit from it.

Additives: this is going to vary from brand to brand. To start with, yes, all the gas in the country comes from just a couple refineries/depots. The primary difference is indeed the additive package ordered with a batch. The additives may or may not modify the octane (IE brand X premium may be brand Y's regular with an additive package that raises the octane). Premium usually has better additives which may be more or may be less of higher effectiveness. Maybe it's the same package. Some brands additive packages have more detergents than others, some of them do more than others. That being said, with all the modern processes and technology, any gas is pretty good. Only really crappy gas or a really lousy drive cycle (lots of short trips that don't get the motor warm) or just bad luck (contaminants) will cause problems. any top tier gas is pretty good, most non-top-tier gas is still good, noname stations are hit or miss. Maybe they didn't order any additives, maybe they bought the gas that's been sitting a month already, maybe it's leftovers from 20 other stations, maybe it's just as good as a top-tier brand they just didn't spring for the certificate.