Premium or regular unleaded

[davesl708]

I use 93 octane pure gas in my push mower. It is now 18 years old and starts with one push of the primer bulb and one pull on the cord.
Weedeaters that used ethanol lasted one season. Since get pure gas and stabil. No issues.
All my small engines get 93 octane pure gas. 87 or 89 octane pure gas is not available in my area.

 

[ForestGrump]

Use the octane the owners manual recommends; as others have said octane is related to compression and altitude. The higher you go the lower octane you can use.
The one advantage premium has over the other grades is the "major" oil companies add more of their additive package to premium. (at least they use to) I worked for both Amoco and BP, both added 10 times the amount of additive to premium. That's not a typo, 10 times the amount.

I worked at an independent refinery in Bakersfield. All refineries have to certify that their products meet ASTM specs. If you don't big big fines. At any different moment you could see just about any major brand tanker filling up at the rack. Each driver had a case of their companies additives in his truck and he would put "one pint" of his additive in each pup. So the refinery PA asked me to get a bottle of Techron, which I did with a 10cc graduated cylinder. Think more is better he put a pint in his towncar. Big big mistake.

Premium gasoline is blende to have a higher octane, period. It is no different from regular. The additives are the same and the same quantity. When sulfur was removed from gasoline and the lead taken out the "new" gasoline are really nice. The different grades will have different distillation parameters but not much.

The additives used are to basically keep the injectors clean and are nitrogen based similar to oilfield corrosion inhibitors. Too much is oh oh. At no time did I ever see any major at the rack add 10 times their additive. The majors bought their products on which refinery had the best "rack price" you would see Shell, Exxon, Mobil, Union Oil, Chevron etc. all loading the same gas and all had their additives on board.

The gasoline after the additives are added still have to meet all the same ASTM specifications. Weights and measures would often test point of sale products. I doubt if a 10 times would pass specs.

 

[DEWFPO]

Years ago when I worked for Chevron, we put more Techron in PUL than RUL. That was a fact. I can't speak for what their doing now but I can't imagine they changed that. Also, Costco has an additive tank at their fuel stations and add 5X the industry minimum requirement for additives in fuel. They have cards on their pumps that advertise it around here. They've been doing that for a few years. There's plenty of documentation on their website to prove this.

DEWFPO

 

[ForestGrump]

For Chevron one pint each pup regardless of grade. I know of no industry standard for gasoline additives. When fuel injection first started appearing in American vehicles, BMW too, they had major design issues. GM sent a letter to all refiners that they had a problem with their injectors clogging, an engineering problem. With gasolines similar to Chevron and one or two others the problem did not exist. Ford did not have the same issues, BTW. GM said in the letter they were therefore going to recommend the use of only specific brands. I personally saw and read this letter. Basically it was their problem but they were going to blame the fuel.

More additive does not make a product a better product. These additives are nitrogen based corrosion inhibitors and cleaners. They are there to improve injector performance. The primary component of gasoline is a grayish pink often wet distillate with a low octane. It's cheap. Higher octane components are then added to meet the octane grade for the gasoline. One very common additive is toluene, up to 10%. Are you a painter, familiar with VM&P, that is high octane and goes in too.

Too much additive = gunk! Premium gasolines are higher octane as tested on a knock engine, period.

 

[Copperhead]

I worked at an independent refinery in Bakersfield. All refineries have to certify that their products meet ASTM specs. If you don't big big fines. At any different moment you could see just about any major brand tanker filling up at the rack. Each driver had a case of their companies additives in his truck and he would put "one pint" of his additive in each pup. So the refinery PA asked me to get a bottle of Techron, which I did with a 10cc graduated cylinder. Think more is better he put a pint in his towncar. Big big mistake.

Premium gasoline is blende to have a higher octane, period. It is no different from regular. The additives are the same and the same quantity. When sulfur was removed from gasoline and the lead taken out the "new" gasoline are really nice. The different grades will have different distillation parameters but not much.

The additives used are to basically keep the injectors clean and are nitrogen based similar to oilfield corrosion inhibitors. Too much is oh oh. At no time did I ever see any major at the rack add 10 times their additive. The majors bought their products on which refinery had the best "rack price" you would see Shell, Exxon, Mobil, Union Oil, Chevron etc. all loading the same gas and all had their additives on board.

The gasoline after the additives are added still have to meet all the same ASTM specifications. Weights and measures would often test point of sale products. I doubt if a 10 times would pass specs.

Very well stated and all true! When I tanked fuel, indeed, it was the determination of the rack price at the time as to which tank farm I would go load at. Didn't matter who I was delivering to. I never actually added any product to the fuel myself, but would swipe the card that represented the particular customer and various additional additives were automatically fed into the fuel stream as it was shoved onto the tanker.

Am not sure why Costco would go to such extremes in adding product to the fuel. Too much of a good thing can also be detrimental. There is a reason why the folks who make these additives have recommended treatment rates and also explain that there is no benefit to using more. And some additive manufacturers will state that using more than the recommended treatment rate can cause problems. At the very least, it just adds cost. I suppose it gives folks who fill up at Costco some kind of warm feeling knowing that they are dosing their fuel to that level, but there really is no appreciable reason to do so.

Kind of along the red wine is good for your heart argument. It is in moderate amounts. But swigging down a full bottle every day will screw you up more.

 

[cat fever]

I worked at an independent refinery in Bakersfield. All refineries have to certify that their products meet ASTM specs. If you don't big big fines. At any different moment you could see just about any major brand tanker filling up at the rack. Each driver had a case of their companies additives in his truck and he would put "one pint" of his additive in each pup. So the refinery PA asked me to get a bottle of Techron, which I did with a 10cc graduated cylinder. Think more is better he put a pint in his towncar. Big big mistake.

Premium gasoline is blende to have a higher octane, period. It is no different from regular. The additives are the same and the same quantity. When sulfur was removed from gasoline and the lead taken out the "new" gasoline are really nice. The different grades will have different distillation parameters but not much.

The additives used are to basically keep the injectors clean and are nitrogen based similar to oilfield corrosion inhibitors. Too much is oh oh. At no time did I ever see any major at the rack add 10 times their additive. The majors bought their products on which refinery had the best "rack price" you would see Shell, Exxon, Mobil, Union Oil, Chevron etc. all loading the same gas and all had their additives on board.

The gasoline after the additives are added still have to meet all the same ASTM specifications. Weights and measures would often test point of sale products. I doubt if a 10 times would pass specs.

Sorry to disagree with you, but do not compare a rinky dink independent refinery to the "majors".
You stated the drivers were adding the additive there selves; WOW, that would NEVER happen at any reputable refinery. Yes, adding a pint to a car tank of gas would not be a good idea. The federal government only states you have to add a detergent/cleaner to keep the intake system clean. Well, one drop could be considered adding a detergent. Amoco had an extensive research and testing facility in Naperville. They knew what and how much to add without a doubt. All loading at the rack was computer controlled and each brand; Amoco, BP, Chevron, Exxon, Shell etc had there own additive package at our loading rack. When a driver carded in to load they got their company additive in the correct amount decided by their company. If a no name truck (jobber) came in to load they got a basic additive package and the minimum amount. I still work for a "major" oil company and I am one of the gas blenders. ( I make it ) Pretty sure I have a good understanding of whats going on. Even DEWFPO backed my original statement.
My rule is, I only buy gas from branded "majors". It may cost more but I have NEVER had a fuel related problem in any vehicle I've ever owned. That means the mom and pop gas station that has a "major" brand is off limits for me. They will buy from the cheapest spot they can and add anything to the tank including water. Yes, that has been done.
So I will reaffirm my original statement of buying the gas your owners manual states to put in. The engine compression ratios were engineered for a specific octane. More octane (to a degree) will not hurt the engine but it will not help either.

 

[cat fever]

ray66v says;
I read about a new engine being developed, which will now have variable compression.

The COMOC engines or Knock engines that most gas is "finaled" on use this principle. We have 4 COMOC engines. 2 belong to our lab techs and 2 belong to the gas blenders (me). We can adjust "knock/compression" while blending gas with the engine running. However it is done manually at this time. I'm sure some computer wizard can make them adjust based on octane. Of course these engines are single cylinder motors in controlled environments.
Ray66v, the comments you have made in this thread are right on track.

 

[ForestGrump]

Sorry to disagree with you, but do not compare a rinky dink independent refinery to the "majors".
You stated the drivers were adding the additive there selves; WOW, that would NEVER happen at any reputable refinery. Yes, adding a pint to a car tank of gas would not be a good idea. The federal government only states you have to add a detergent/cleaner to keep the intake system clean. Well, one drop could be considered adding a detergent. Amoco had an extensive research and testing facility in Naperville. They knew what and how much to add without a doubt. All loading at the rack was computer controlled and each brand; Amoco, BP, Chevron, Exxon, Shell etc had there own additive package at our loading rack. When a driver carded in to load they got their company additive in the correct amount decided by their company. If a no name truck (jobber) came in to load they got a basic additive package and the minimum amount. I still work for a "major" oil company and I am one of the gas blenders. ( I make it ) Pretty sure I have a good understanding of whats going on. Even DEWFPO backed my original statement.
My rule is, I only buy gas from branded "majors". It may cost more but I have NEVER had a fuel related problem in any vehicle I've ever owned. That means the mom and pop gas station that has a "major" brand is off limits for me. They will buy from the cheapest spot they can and add anything to the tank including water. Yes, that has been done.
So I will reaffirm my original statement of buying the gas your owners manual states to put in. The engine compression ratios were engineered for a specific octane. More octane (to a degree) will not hurt the engine but it will not help either.

Wow, testy, aren't we. In the 1980's additives were added by the drivers at the rack. No automation such as you speak of was available at the time. Our lab in our rinks dink refinery was state of the art and we had Exxon, Texaco and weights and measure etc visit to see our state of the art instrumentation and methodology. Specifically our $50,000 Horiba Sulfur analyzer which could detect <1 ppm. I taught weights and measures how to set up the Horiba they were buying and advised Texaco.

Our diesel was the best in Southern CA, the Texaco lab people bought ours verses their rack product.

Our jet fuel, JP5, was used for the 747 that ferried the space shuttle from Edwards. It was also used in the NASA test of a product for jet fuels that would keep jet fuel from exploding and burning in a crash, it didn't. I'm sure you have seen the video.

BTW I worked for Shell, too! Don't get me started on pumping and blending... I've been in Exxon's Houston R&D labs, Haliburton, Shells two facilities in Houston, Mobil etc. for specific issues, they had.

For those listening in all commercial fuels must pass ASTM Specifications. In the western district, including Hawaii, there are about 35 -40 refineries. Each month one of those refineries sends a one gallon sample of a gasoline, and diesel rack product to each of the other refineries for mutual testing. Results are sent in to the ASTM which then statistically evaluates the results, in order. Whoa is the refinery near the bottom of the list, whoa is the lab whose data was tossed expect visitors the next morning. All the refineries in the western district produced quality products. I won't knock any of them, I respect these guys. We thought we were the best. We had the government contract for jet fuels and supplied all the bases in lower California.

State regulatory agencies often would go to a station and pull samples, you still had to pass specs.

I got a call one morning from the owner and the refinery manager. Seems that I had given a quart of TEL, which was becoming a rare species, to the Texaco refinery - free, $400. They heard about it at the local Petroleum club meeting that night from the GM and VP of Texaco. Everyone was happy happy happy because the refinery would have to shut down their gasoline racks till their lab got ahold of some or to bring their samples to our lab.

There are small specialty refineries that produce excellent products, 20,000 to 40,000 BOD.

 

[buickanddeere]

No alcohol and the highest octane at the pump for the chainsaws, generators, string trimmers, snowmobiles etc . If parked for the season they have some 100LL run through the carb.

 

[ForestGrump]

No alcohol and the highest octane at the pump for the chainsaws, generators, string trimmers, snowmobiles etc . If parked for the season they have some 100LL run through the carb.

The manufacturer's and dealers recommend 91 octane for all small two cycle engines for high altitude use.