High Octane Gas?

[cccougar]

I have a 2014 2500 HD Ram with the 5.7 Hemi.. and have been putting reg gas in it. With the camping season upon us and towing every other weekend, should I be putting a higher octane in it? Will this help with performance? This is my first season towing- so I am very new to this.
Thanks.

[philh]

Turtle n Peeps wrote:
You can keep on saying it, but it's still not correct.

You might have heard of Sunoco? They make a few gallons of gasoline / day.

Actually, it's on Sunoco's site where they list the Btu and octane levels of the various gasolines.

[eichacsj]

Octane recommendation has to do with compression ratio. The MFG recommendation is based on that. If you modified your engine to increase the compression ratio then you may need to deviate from the MFG instruction. If not follow the MFG.

On mine I do find I get better performance from mid grade (89). Some states the low grade can get to 84, 85 octane so don't just hit the button, look at the octane at the pump when traveling. In today's engines you can't hear the "ping" because the computer adjusts it out, i.e. retarding the timing to stop it, which can lower performance, so don't try to listen for that. If it gets that bad you cna hear it then you have one of 2 issues, a sensor problem or have exceeded the the rating to the computers extreme, like running 84 where you should run 87.

[majorgator]

FelixTC wrote:
Cccougar,
So many misconceptions. Google octane ratings and fine out what the experts say. Using a higher octane than what your truck calls for is like taking two one-a-days instead of one. It does absolutely no good. Regardless if you're towing or not. Anyone who says different is taking a placebo and letting their imagination get the best of them. You're not going to get better gas mileage or performance.

Actually, taking even a single one-a-day does absolutely no good. The ingredients found in one-a-day don't mirror what the body actually needs, and are really chemically contrived. We should all be looking for natural sources of vitamins. There is such thing as vitamin overdose for things like Vit A, B, D, but that's only due to those that are developed in a lab by mixing chemicals. This is not a concern for natural sources of those same vitamins.

Sorry, I didn't want to be the first one to veer off on a tangent on this thread :B

[Turtle_n_Peeps]

Higher octane fuels have slightly less energy (Btu), BUT, have a slower burn rate which allows for higher compression through mechanical means, aka compression ratio, or artificial means, aka spark advance, and will generate more power from slightly less energy.

You can keep on saying it, but it's still not correct.

SUNOCO wrote:
You might be surprised to learn that some of the highest octane fuels may also be some of the fastest burning fuels!

You might have heard of Sunoco? They make a few gallons of gasoline / day. :W I would think they know what they talk about and they say the same thing I'm saying: Octane and burn rate are mutually exclusive. One has nothing to do with the other. Link

Read post #12 for more facts.

BTU's have nothing to do with power. Zero.

Gasoline and nitromethane is a perfect example.

BTU's of one gallon of gasoline= around 113,000.

BTU's of nitromethane= around 47,000.

Octane rating of nitromethane is VERY, very low; (off the scale in fact) but yet it puts out the most power. Pretty much contradicts what you have said that high octane fuels have less BTU's but can put out more power.

As you can see, nitro has about half the BTU's of gasoline but what do you want to use in an engine to make the most power? There is a reason that those dragsters on TV use nitromethane for fuel instead of gasoline. In fact nitro puts out over twice the power of gasoline engine for engine.

Now lets use an example more RV'ers can relate to: E85 and gasoline. After all, there is a lot of RV'ers on the road that have flex fuel engines and in the mid west they have a choice of which fuel to use.

E85 has around 82,000 BTU's / gallon. We learned from the above example that gasoline has around 113,000 / gallon.

Now, what puts out more power? Lets see what Ford has to say about this. They make some pretty cool engines. (gasoline anyway :W)
Gasoline vs E85 power test.

As anybody can see from the links I have posted that: Burn rate; Octane; and Power output are all mutually exclusive of each other just as I have been saying all along.

[BenK]

Suggest defining how the ICE fuel/air mixture/compression/etc
works in the combustion chamber...

My first swag without having to post links... :B

The air/fuel mixture going into the combustion chamber is compressed
to increase the potential PSI after ignition...even more potential
PSI if the timing is advanced before top dead center...

For it is all about the PSI on the piston top...that is what makes
the power to drive the rear axle via the food chain from the ICE
to that axle(s)

PSI...pounds per square inch...so with the same PSI...you can
have more power with a larger dia piston...or more PSI on a smaller
piston dia...or any combo of that.

Then comes the crank offset and the lever arm on the crank...and
a bunch of mechanical stuff that goes with that...like gearing/etc

Ignition of the air/fuel mixture inside the combustion chamber is
NOT an explosion...that would break things in a hurry...it is a 'burn'

But...when the ICE is working hard and HOT...that air/fuel mixture
only needs ignition to light off (either an explosion or burn)

A controlled burn is when it is ignited when desired/designed.

Knock, pre-ignition, etc is when it goes off not according to plan/design


It is NOT a burn, but an explosion and is self ignited by whatever
conditions in the combustion chamber

Octane rating of the fuel is its resistance to pre-ignite

There is a 'knock sensor' in most all modern gassers. That sensor
is the eyes/ears for the computer(s) and the software algorithms
will then tell the computer to back off ignition timing (less
potential PSI developed...therefore less power)

With higher octane fuel...it will 'seem' to make more power, but
in reality...just allows more power it was designed to develop in
proper conditions...where as the computer(s) would have phased
back the amount of potential power...

Why using higher octane will deliver more power under those harsh
conditions...and potentially better fuel mileage...as the ICE will
be up to higher power levels

[philh]

Turtle n Peeps wrote:

I'm confused? :h You were talking about BTU's and then in your last sentence you talk about burn rate. Those are two different things entirely.

LOL

Octane, Btu, Burn Rate all work together 🙂

Higher octane fuels have slightly less energy (Btu), BUT, have a slower burn rate which allows for higher compression through mechanical means, aka compression ratio, or artificial means, aka spark advance, and will generate more power from slightly less energy.

Damn that is a long run on sentence 🙂

going from 87 to 89 is not a bad thing, is only slightly more expensive. Especially in HOT weather while towing, might reduce some chances of spark knock and subsequent reduction in spark advance. Problem is when going all the way to 93 octane. I contend there are zero gains, and one will actually develop problems from premium on an engine designed to run on regular.

[Turtle_n_Peeps]

philh wrote:

Turtle n Peeps wrote:

Technically, saying that premium has less BTU's is like saying I just took a leak in the ocean and now it's higher. Is it true? Ya, but.........:R.

More like adding to a 55gal drum 🙂 I used to have the energy numbers, but they are long gone 😞

Point being, it's the burn rate of premium that's an advantage to engines built for higher octane fuel, and to a lesser extent engines tuned to run it.

I'm confused? :h You were talking about BTU's and then in your last sentence you talk about burn rate. Those are two different things entirely.

Since this is a towing forum lets talk about fuel terms and what they do and mean to us as RV'ers (with a little talk about non-RVing fuels thrown in.)

BTU's; British Thermal Units:
A measure of heat units. What does this mean to us? The more BTU's a fuel has the better your mileage will be for a given engine. (This is why E10 will net us about 4 to 5% less mileage than straight gasoline.) This is a BIG reason a diesel engine gets around 30% better mileage than a gasoline engine. A fuels BTU's has NOTHING to do with the power it can put out. As a matter of a fact it's inverse proportional for every fuel I can think of. (less BTU's = more power).
(As an RVer, get the fuel with the highest BTU's if you want the best mileage; that would be good ol #2 diesel for you that don't know. Or straight gasoline for you with gasoline engines)

Burn rate: How fast any given fuel burns. Usually measured in milliseconds. As stated, burn rate has next to nothing to do with the octane of the fuel. One can make a fuel with a high octane rating and slow burn rate; or the other way around. Fuel air ratio means WAY more on how fast or slow a fuel burns than the octane rating. A lean mixture burns slower than a rich one. Burn rate of a fuel is also mutually exclusive of the amount of power an engine puts out. IOW's a very slow burning fuel can make a lot of power and a very fast burning fuel can make a smaller amount of power.

Octane Rating: A figure indicating the antiknock properties of a fuel, based on a comparison with a mixture of isooctane and heptane.
Octane is mutually exclusive of the amount of BTU's a fuel has or the amount power the fuel can produce.
What can octane do for us RV'ers? That is a super complex question now days. In the old days of distributors and carburetors you would just run the fuel that did not "ping" in your truck and you would be good to go. If your truck did not ping on regular that's what you would run. You would not pick up any mileage at all if you ran premium if that was the case.

Now days things are a LOT more complex. A computer decides up to a 1000 times a second whether the fuel is up to the task or not. It gets its info from knock sensors in the engine and intake air thermometers in the intake and many, many, many more sensors. From all this info it can advance the timing (Good for mileage) or give it more fuel (bad for mileage).



I know, I know, I know; some of you are asking why as an RV'er can't I just open my manual and just read what the OEM says to run and be done with it? Don't they know what's best? Welllllllll, sort of.

OEM does not know the conditions you tow in. They might say, "use regular fuel while towing." And this might be fine if you are towing in Denver when it's 70 degrees out. Or even in 2000 foot altitude in 40 degree weather.

But if you happen to tow at sea level and it's 100 degrees out your engine will likely drop timing out like a big dog (bad for performance and fuel mileage) and add fuel (also bad for fuel mileage) to prevent detonation. In this case premium would be a far better fuel to run despite what the OEM tells you.

The reverse is also possible. Ever wonder why towns like Denver sell only lower octane fuel when the OEM say's to use only "x" octane fuel? Well now you know! You don't need real high octane fuel waaaaay up there!


This is why there is so much debate about the octane of fuel to run on towing forums. We have people saying that they tow with X brand of truck and the OEM says it's recommended to run premium fuel while towing. But they say they run regular fuel while towing and it runs just fine!! Then there are people that say they tow with brand x truck and they run premium fuel and they pick up mileage over regular fuel.

How can they both be right? It's because they don't see the same conditions either one sees and the computer is making different decisions for different conditions.

The bottom line is this. It's best to use the fuel OEM recommends to use or if you really want to split hairs like some do, buy the fuel for the conditions you will be towing in. Regular conditions call for regular fuel. Harsh conditions call for a more premium fuel.

Or you can be like me and forget all this talk about gasoline and buy a diesel and jam #2 in it and get 12 MPG at 70 MPH. :B

[Hannibal]

Turtle n Peeps wrote:


Technically, saying that premium has less BTU's is like saying I just took a leak in the ocean and now it's higher. Is it true? Ya, but.........:R.

Dang Peeps! You da man!

But seriously, my 5.4L F250 manual states a minimum of 87 octane, not a maximum. The minute power loss to running 89 octane is imeaserable. The power loss from the ecm retarding timing due to preignition is obvious. If I was racing my F250 at high rpm, I'd run 87. While towing it wants to drop into O/D and that's where it benefits from 89.

[philh]

Turtle n Peeps wrote:

Technically, saying that premium has less BTU's is like saying I just took a leak in the ocean and now it's higher. Is it true? Ya, but.........:R.

More like adding to a 55gal drum 🙂 I used to have the energy numbers, but they are long gone 😞

Point being, it's the burn rate of premium that's an advantage to engines built for higher octane fuel, and to a lesser extent engines tuned to run it.

[Turtle_n_Peeps]

marcsbigfoot20b27 wrote:

philh wrote:
{sigh}

Higher octane fuel has LESS Btu's of energy per gallon. What it does have is a better controlled burn rate under higher pressures.

Run the mfg recommended fuel.

I run premium in my 5.7L only because my engine has been retuned to use the higher octane fuel.

Another issue with premium, today's "gasoline" deteriorates over time. If you get a station that doesn't sell enough premium fuel, the quality can actually be lower than regular or mid grade. Many stations blend regular and premium to get to mid grade... but not all. Finally, you can run into stations falsely selling regular as premium. I can tell within a mile of leaving a station if I truly pumped good quality premium. Because my engine is after market tuned for it, spark advance gets pulled very quickly with lower grade fuel.

Did I mention, run the mfg recommended fuel?

Oh please cite where higher octane gasoline has less BTUs .......and I don't mean something trivial like 200 BTUs out of ~115,000 per gallon avg.

Technically, saying that premium has less BTU's is like saying I just took a leak in the ocean and now it's higher. Is it true? Ya, but.........:R.

[marcsbigfoot20b]

philh wrote:
{sigh}

Higher octane fuel has LESS Btu's of energy per gallon. What it does have is a better controlled burn rate under higher pressures.

Run the mfg recommended fuel.

I run premium in my 5.7L only because my engine has been retuned to use the higher octane fuel.

Another issue with premium, today's "gasoline" deteriorates over time. If you get a station that doesn't sell enough premium fuel, the quality can actually be lower than regular or mid grade. Many stations blend regular and premium to get to mid grade... but not all. Finally, you can run into stations falsely selling regular as premium. I can tell within a mile of leaving a station if I truly pumped good quality premium. Because my engine is after market tuned for it, spark advance gets pulled very quickly with lower grade fuel.

Did I mention, run the mfg recommended fuel?

Oh please cite where higher octane gasoline has less BTUs .......and I don't mean something trivial like 200 BTUs out of ~115,000 per gallon avg.

[philh]

{sigh}

Higher octane fuel has LESS Btu's of energy per gallon. What it does have is a better controlled burn rate under higher pressures.

Run the mfg recommended fuel.

I run premium in my 5.7L only because my engine has been retuned to use the higher octane fuel.

Another issue with premium, today's "gasoline" deteriorates over time. If you get a station that doesn't sell enough premium fuel, the quality can actually be lower than regular or mid grade. Many stations blend regular and premium to get to mid grade... but not all. Finally, you can run into stations falsely selling regular as premium. I can tell within a mile of leaving a station if I truly pumped good quality premium. Because my engine is after market tuned for it, spark advance gets pulled very quickly with lower grade fuel.

Did I mention, run the mfg recommended fuel?

[Hannibal]

Funny how some people Google a topic and parrot their findings trying to appear smart. Some of us have many years of first hand experience towing with many different engines.

[FelixTC]

Cccougar,
So many misconceptions. Google octane ratings and fine out what the experts say. Using a higher octane than what your truck calls for is like taking two one-a-days instead of one. It does absolutely no good. Regardless if you're towing or not. Anyone who says different is taking a placebo and letting their imagination get the best of them. You're not going to get better gas mileage or performance.