Home Forums Hunting & Shooting Hunter's Campfire Premium gasoline vs. Mid-grade unleaded

Ethanol lowers mileage and increases cost of food and fuel at the same time...

Ok,onto the question, I don't regard Lexus as cheap vehicles.

Worrying about cost of premium after buying a Lexus boggles my mind.

But the question is fuel grades... I forgot and put low octane in my airboat one weekend a while back. It dieseled all day long. The next day the oil pressure line snapped and locked the engine before I could catch it.

It was only an engine valued at about 11K to replace....

YMMV

If Al Gore wasn't into climate and instead he sold gasoline, he'd sell ethanol fuels. A huge con game "fueled" by lobbyists.

Use what your vehicle owner manual recommends and don't let your next door neighbor or a stranger on the internet decide what is best for your particular car. Same with engine oils. Many newer cars that are designed for modern blended oils for longer life get nothing but a diet of regular oil with super cheap and inefficient oil filters at cheap change locations. Engine life suffers.

I know for a fact that with a 7.0 L Camaro, anything less than 93 octane which I have to buy in some higher elevations (where sometimes only 87 or 91 are available) retards ignition and definitely affects overall performance. I had a 400+ mile weekend trip this past weekend and averaged 22.7 miles per gallon on 93 octane with both freeway and city driving, and I didn't baby the speed for an MPG rating.

Why would you want to baby it if you bought a higher performance car? And running it on cheaper gas is definitely not doing the engine any good. Again, use what the car was designed for in both gasoline and oils and you'll save money in the long run.

It may run fine, but you WILL NOT get the fuel economy from the higher ethanol blends. They are nothing but a rip off and put just as much crap in the air as straight gas.

I burn the e-10 in my vehicles, but I will not go any higher than that.

Nothing but pure gas in my chainsaws, mowers, etc.

I get the same mileage with E30 in the Durango as I ever got with E10 . The University of Mn has run some tests with different vehicles and found that a blend from E30 to E20 was optimum for fuel mileage with many rigs

I have a GS 350 and fill it with the cheap stuff without complication. I am also at 1000' elevation, so take that into consideration. I've had one Lexus or another since 1992. I've fed them 92 octane and 87 octane. I run them for 160,000 and they run better when I turn them in than when new. Very well build and engineered autos.

Like others have pointed out, the fuel computer will adjust. If you notice a performance difference with 87 or 89, then you have the anser and need the good stuff. Otherwise, save the cash.

Excepting the fact that I've NEVER gotten as good a mileage out of ethanol blended fuels as with non.

AND the fact that ethanol is hygroscopic (i.e., attracts water) and will, at some point, screw up whatever it's in..

No thankee...

Search web for non alcohol gas.....
Lots of stations out there.
But, I drive a pre def diesel.....

In general, higher octane gasoline burns cleaner than lower octane gasoline so the automobile manufacturers have an interest in recommending the higher octane fuels so they can claim lower overall fleet air pollution emissions.

Disclaimer: I work for a company that licenses petroleum refining technologies so I have an interest in ever higher octane standards. However, I DO NOT speak for my employer about this or any other issue. I only write my personal opinions.

Oh, and my wife and I only burn regular gasoline in both Lexus cars we own.

Pure gas, without ethanol, will give you better mileage, regardless of the octane. This has been my experience with a number of different vehicles.

I used to be a gasoline blender, though it was before ethanol got introduced to the mix. The octane of the gas you buy will meet the posted specifications on the pump, but you can bet it won't exceed the spec. And Uncle Sam watches real close, so if you sell an 87 R+M/2 octane gas, it had better meet that spec. You never know when they'll pull a sample and test it. They are not forgiving people. Over the years I suppose I blended billions of gallons of gasoline, and we tested every batch and had a test certification issued by an independent testing firm. I was scared of messing up and having the Feds on me.

Gasoline is made up of an assortment of blend components, and for me it was what I had on hand that would blend up to the spec. If I needed more octane, I'd buy the volume of higher octane that I needed. It's not just octane that you blend for. There are distillation curve temperatures to meet, and a vapor pressure. Alcohol gives decent octane, but has a low midpoint, which has to be compensated for by one of the other blendstocks. What I believe, but can't prove (these days) is that today's ethanol gasoline has a lower BTU content than non-oxygenated gasoline. That would lead to lower mileage.

Also of note is that I had to blend for the region where the gasoline was going. Each region does not have the same specification requirements (octane and RVP, for instance). And there were seasonal variations to meet.

As for what to run in your car or truck, you would be wise to run the fuel/octane that the manufacturer suggests.

The power of gasoline and Ethanol is rated by BTU, Gasoline contains 114,500 btu's per gallon, Ethanol (E100) contains 76,100 btu's per gallon.

Anytime you add ethanol to gasoline you reduce it's power. Gasoline is a far better choice for Engines than ethanol is by far.

The .gov demands better mileage out of car manufacturers and they reduce the efficiency of gasoline at the same time. Fuqking dunces is what they are.


For you guys that can't get ethanol free fuel for your small engines use a product called Ethanol Shield, Add this to your E10 at the rate of 1 ounce to five gallons and you will have no worries.

My daughter's 1998 Nissan Pathfinder with 180K on the clock runs decidedly better on 87 without ethanol than either 87 or 91 with ethanol. My daughter was complaining about the higher cost of fuel, 'cause Sam's Club is selling 87 with ethanol for $1.919 per gallon, but they don't sell any non-ethanol fuel, so she's paying $2.359 per gallon.

12344mag made a good point on the BTU's, and ihookem may not be clear that a tested octane is a blended octane. You don't blend up Premium and then add the alcohol for a higher octane. The blend Target is to hit all the specs that matter, while not giving valuable specs away for nothing. It's all about the money. I had huge tanks of various blendstocks and more on the way in tanker ships, and I could buy what I still might be missing. Let's say your latest test blend hit the octane spec and the RVP (Reid vapor pressure), but was shy on the midpoint. I'd have to shop around in my tanks to see what I had to raise the midpoint but not disturb the RVP and not give away octane. Octane is money. Computers really came in handy for optimizing blends.

Regarding BTU, I don't remember ever testing a blend for BTU content, which is why I said I suspected that the oxygenated gasoline was light on BTU's. But, an oxygenated gasoline blend could easily be low on midpoint, which would indicate low BTU content, but I would have had to correct that in order to meet spec. To correct it, I'd likely have to pull some of the stock (in a computer simulation) and replace it with some other stock to raise the midpoint enough to meet spec. And if I did that, I'd be raising BTU content.

That's why I said that I suspect the oxygenated gas would possibly be light on BTU's, but I don't know that for sure. All I do know is that oxygenated gasoline gives worse mileage in my vehicles, so I'm thinking that it has to be a function of BTU content.

Gasoline blending was a combination of science and the black arts. Most specs didn't blend in a linear fashion, so no matter how many simulations you ran, it was still often a guess that would have to be marginally corrected before shipping.

In a gallon of E10 gasoline you have a 10% Ethanol content. to make this you remove 12.8 Fl ounces of gasoline out of the gallon and you replace it with 12.8 Fl ounces of Ethanol, I'm sure the blending process is much more complicated than just adding or subtracting but I'm trying to make this simple.

With Gasoline at 114,500 btu and Ethanol at 76,100 btu you have less power in the gallon of E10 than you do in the gallon of E0.

ANY engine burning E10 will be less efficient than an engine burning E0.

As to the op's original question with out knowing the computer tuning of the Lexus it would be impossible to tell whether the lower octane gas would be bad for it or not.

I have a friend who has a LS3 engine in his sand buggy, he is putting 1200 hp to the wheels this is a very high performance engine and has to have the computer tuned to what ever is in the tank. If it is tuned for e10 and he uses pure gasoline he'll toast it in a very short period of time.

Performance and mileage?

Energy quotient.