Fuel Question

[Evo2700]

Just out of curiosity, for those of us with gas engines, is there a preference on using the lower octane fuels to save some cash at the pump or do you splurge on the higher octane when towing your trailer? And how about types of gas, how many people are sold on a certain brand of gas.

Personally, I use regular in my tuck when not towing and the higher octane when my trailer is hooked up. I also prefer Chevron w/ Techron. I have, what might possibly be a false sense of security that their gas is better for my truck, but also their gas stations tend to be cleaner and bigger.

I've heard the higher octane burns faster causing less gas mileage and I've also heard it's better combustion for the engine. Additionally, I've heard both side of the fence for if the Techron in Chevron gas actually helps or if it's just a marketing ploy.

Other opinions on this are interesting to me.

[B47]

Originally Posted by Evo2700

Just out of curiosity, for those of us with gas engines, is there a preference on using the lower octane fuels to save some cash at the pump or do you splurge on the higher octane when towing your trailer? And how about types of gas, how many people are sold on a certain brand of gas.

Personally, I use regular in my tuck when not towing and the higher octane when my trailer is hooked up. I also prefer Chevron w/ Techron. I have, what might possibly be a false sense of security that their gas is better for my truck, but also their gas stations tend to be cleaner and bigger.

I've heard the higher octane burns faster causing less gas mileage and I've also heard it's better combustion for the engine. Additionally, I've heard both side of the fence for if the Techron in Chevron gas actually helps or if it's just a marketing ploy.

Other opinions on this are interesting to me.

Personally I have always used what my cars manufactures have recommended - that being the 87 octane juice.

In the "older days" with the higher compression engines in the muscle cars,the higher octane fuel might have been necessary,but in today's computer burdened engines I just stick with the 87 octane.

I remember from the past when the major brands of gasoline all had their own special additives such as Mobil with their detergent additive that cleaned your engine - their ads showed the front of a washing machine.

I'm not a fuel engineer,but I'm not sure today that each major brand gasoline provider doesn't get their fuel from the same spigot.

[mud yapster]

Higher octane burns slower not faster and is made for higher compression ratio motors. If your motor is designed to run on 87 octane and your using the higher octane in it your wasting your cash.

[RhoZeta]

Originally Posted by Evo2700

Just out of curiosity, for those of us with gas engines, is there a preference on using the lower octane fuels to save some cash at the pump or do you splurge on the higher octane when towing your trailer? And how about types of gas, how many people are sold on a certain brand of gas.

Personally, I use regular in my tuck when not towing and the higher octane when my trailer is hooked up. I also prefer Chevron w/ Techron. I have, what might possibly be a false sense of security that their gas is better for my truck, but also their gas stations tend to be cleaner and bigger.

I've heard the higher octane burns faster causing less gas mileage and I've also heard it's better combustion for the engine. Additionally, I've heard both side of the fence for if the Techron in Chevron gas actually helps or if it's just a marketing ploy.

Other opinions on this are interesting to me.

You have heard wrong. Google is your friend! If you do just a little bit of research you will find that octane is NOT a performamce booster.
It SLOWS combustion down so that engines with higher compression wil not pre-detonate (like a diesel). Using it on an engine that does not need it is not only a waste of money but you are causing long term damage to your catalyst system due to excessive unburnt fuel being dumped in your catalytic converter.

There are many people who have many anecdotes on more power, better mileage etc etc by simply using a higher octane fuel in a vehicle that is built to run on 87 and when I hear them I always just nod my head and smile, and anybody who knows what octane ACTUALLY does will do the same.

Now, there are vehicles with high performance/high compression engines that can benefit from higher octane but, they can also run 87 if that is all that is available and the computer will adjust accordingly.
But again, the performance does not come from high octane.

[Evo2700]

When you google it you will see that some articles say it makes a difference and some say no difference. That's why I figured I would see what the consensus on here is.

[Happy Vibe]

In the Ram with the 5.7 it says to use 89 for the best performance. With mine I tried using 89 and 87 while towing and I did not notice a difference, but my trailer is so light I don't need to use a lot of throttle to get going. My VW says to use 91 min so I always use the high octane in it.

[indybp57]

If you are not experiencing spark knock (pinging or pre-detonation) when the engine is pulling hard then there is no benefit to using higher octane fuel than what the manufacturer recommends. The exception might be if you have a pcm tune that changes the ignition timing to increase engine performance.

[RhoZeta]

Originally Posted by Evo2700

When you google it you will see that some articles say it makes a difference and some say no difference. That's why I figured I would see what the consensus on here is.

Indeed you will find many opinions out there. Again, lots of people have lived their entire lives thinking higher octane = better performance, was a great marketing ploy during 60's and 70's, "ethyl" "hi-test" and the like, all hogwash marketing. Infact it was so ingrained in the American psyche that The Feds finally passed laws requiring oil companies clean up their act and do truth in advertising and to not push the false idea that higher octane was better for your car. They also made it mandatory that any additives added to fuels, eg "Techron", be the same amount in all grades instead of the ploy of having more in premium so people would unnecessarily buy it even tho their car could not use it.

Research what octane actually is, you will get a good understanding and be able to make an informed decision at the pumps instead of a marketing ploy.

[Happy Vibe]

Indy I would agree with you years ago but in a modern engine the computer can adjust many parameters to reduce the pinging before you are even aware that it is happening. This can reduce the amount of power the engine makes. In a turbo it will reduce the amount of boost.

[mud yapster]

Originally Posted by RhoZeta

Indeed you will find many opinions out there. Again, lots of people have lived there entire lives thinking higher octane = better performance, was a great marketing ploy during 60's and 70's, "ethyl" "hi-test" and the like, all hogwash marketing. Infact it was so ingrained in the American psyche that The Feds finally passed laws requiring oil companies clean up their act and do truth in advertising and to not push the false idea that higher octane was better for your car. They also made it mandatory that any additives added to fuels, eg "Techron", be the same amount in all grades instead of the ploy of having more in premium so people would unnecessarily buy it even tho their car could not use it.

Research what octane actually is, you will get a good understanding and be able to make an informed decision at the pumps instead of a marketing ploy.

X2

[acadianbob]

Originally Posted by Happy Vibe

Indy I would agree with you years ago but in a modern engine the computer can adjust many parameters to reduce the pinging before you are even aware that it is happening. This can reduce the amount of power the engine makes. In a turbo it will reduce the amount of boost.

Yep!

[Kaadk]

I remember having a debate with a couple of friends a while ago about Octane vs MPG. So, I sat down one day and figured out that based on the price difference I needed to achieve something like +0.5 MPG better using the premium over using the regular to make up the difference in cost (at the current prices that day). Now, that doesn't sound like much but considering I'm only getting about 8-9 mpg towing that's a significant percentage difference.

Now on the other hand though, my very first car only got Petro-Can Super Clean Premium. It was an old 89' Aries that had been sitting for a while and had developed fuel issues. Only that particular brand of premium could be used without causing engine knock. A cheaper grade and/or a competing brand that didn't have whatever the super clean agent was would just turn into issues for me.

Originally Posted by Happy Vibe

In the Ram with the 5.7 it says to use 89 for the best performance. With mine I tried using 89 and 87 while towing and I did not notice a difference, but my trailer is so light I don't need to use a lot of throttle to get going. My VW says to use 91 min so I always use the high octane in it.

I'll have to double check my book. My Ram with the 5.7 just says to use regular, so it gets the 87.

[RhoZeta]

Originally Posted by Kaadk

I remember having a debate with a couple of friends a while ago about Octane vs MPG. So, I sat down one day and figured out that based on the price difference I needed to achieve something like +0.5 MPG better using the premium over using the regular to make up the difference in cost (at the current prices that day). Now, that doesn't sound like much but considering I'm only getting about 8-9 mpg towing that's a significant percentage difference.

Now on the other hand though, my very first car only got Petro-Can Super Clean Premium. It was an old 89' Aries that had been sitting for a while and had developed fuel issues. Only that particular brand of premium could be used without causing engine knock. A cheaper grade and/or a competing brand that didn't have whatever the super clean agent was would just turn into issues for me.

That would only work if you actually did get better mileage from using higher octane fuel, which you can not.
The BTU content is the same so it is impossible to achieve better mileage.
Most likely, that whipped Dodge aries had some serious mechanical issues and was out of wack on timing, beyond what the PCM could correct and the only way to prevent pre detonation was to use high octane fuel. The higher octane chemically slowed down the combustion burn which eliminated the rattle. You probably had a knock sensor that was inop as well. I am also guessing you had a constant "service engine soon" light on?

[Kaadk]

Originally Posted by RhoZeta

That would only work if you actually did get better mileage from using higher octane fuel, which you can not.
The BTU content is the same so it is impossible to achieve better mileage.

Oh, I agree, but they didn't believe that so I did the math assuming that you'd have to travel just as far one one gallon of premium, as you could on the 1.x gallons of regular you can buy for the same cost. It worked out (at that time) that I'd need about an extra 0.5 mpg in order for that to be true.

Originally Posted by RhoZeta

Most likely, that whipped Dodge aries had some serious mechanical issues and was out of wack on timing, beyond what the PCM could correct and the only way to prevent pre detonation was to use high octane fuel. The higher octane chemically slowed down the combustion burn which eliminated the rattle. You probably had a knock sensor that was inop as well. I am also guessing you had a constant "service engine soon" light on?

Nope, the engine light was usually off, unless I used a different brand gas. When the replaced the fuel injectors they told me the tank was full of sludge from sitting so long and they wanted me to drop and flush the tank (for about the same as what was paid to buy the car). Instead, since the super clean ran, I used that for the 2 years it had it before I traded it in on my 2nd (and very first brand new) car.



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[Super Thirty]

I have to check my book but thought it said the engine required a minimum of 87 octane. My 6.0 l gets 87 octane.


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[Evo2700]

All good info. I'm going to dig out my truck's owner's manual and confirm what it says about which type of gas.

[Happy Vibe]

From the manual : 5.7L Engine
This engine is designed to meet all emissions
regulations and provide satisfactory
fuel economy and performance when using
high quality unleaded gasoline having
an octane range of 87 to 89. The manufacturer recommends
the use of 89 octane for optimum performance.
The use of premium gasoline is not recommended, as it
will not provide any benefit over regular gasoline in
these engines.

Interesting that they even state that premium fuel will not help performance.

[Kaadk]

Yep, I pulled out the book and sure enough, it says 89. Looks like I've been under octaning it for the last 4 years.

Oh well, no problems have arisen that I can see and since it does say 87 or 89 I don't think I've done any harm, but I'll have switch to the 89 for a little while to see if it makes any difference.




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[Evo2700]

My book says 87 acceptable 89 preferred for the 5.7. I guess I will start saving some money by not getting the premium.

[M&K Hoffman]

Having worked for the country's largest independent oil refiner for 41 years, I would like to share some of the knowledge I gained during that time. For the last 25 to 30 years of that time, one of my duties was setting up, maintaining and auditing the systems that inject the additives into all the various fuels; gasoline, diesel, kerosene and home heating oil, as they are being loaded for transport. Back in the days of leaded gas, many of the additives were primarily dyes. These days all gasoline, which of course is unleaded, is required by the EPA to contain a certain amount of IVD (Intake Valve Deposit) or detergent additive. Four automakers, BMW, General Motors, Honda and Toyota, feel that the current EPA minimum detergent requirements do not go far enough to ensure optimal engine performance, but there is a minimum required. Side note, there was one customer, which is a large and well known convenience chain in PA, did pay for an extra percentage of IVD, but after several years cut back to the standard minimum required amount, which is referred to as the LAC or lowest additive concentration.
Gasoline of different brands can and does come from varying sources. It is called the exchange. Over the years I worked on injectors for Mobil, Exxon (prior to those two merging) Sunoco, Shell, Gulf, Atlantic and BP. The refinery I worked for has its own brands,primarily KwikFill. Occasionally technicians from the various companies would come in to check their systems and at those times I would work with those techs. During one of those visits, the Exxon tech. told me that other than the required IVD content, their additive contained a proprietary chemical element the purpose of which was a fingerprint for their gasoline. Exxon had a lot of independently owned service stations and occasionally owners would buy gasoline off the black market to sell under the Exxon brand. The "fingerprint" allowed them to catch these owners.
Anyway, excuse the rambling, the previous comments on octane are correct. If it is not recommended for your engine, you are wasting money. As far as the 89 octane goes, it can be hard to find in some areas and it was never refined at the refinery I where I worked. I will not swear to it, but I would bet that most 89 is "made" the by the same method. It is splash blended. Meaning a certain amount of 87 octane is loaded into the compartment and then the amount of higher octane, 93.5 in the case of the refinery I worked at, is added to raise the 87 to 89 which here is called mid-grade.

Hopefully a few of you find this interesting at the very least!