Split: Off-Topic about Octane

[ionbeam]

On this same note, I decided to make a change to my vehciles. I use air in the tires, and I breath oxygen. Since that air must have lots of oxygen in it, to sustain life, more must be better. I decided I would fill all my tires with pure O2. I could have used nitrogen, but we can't breath Nitrogen, so O2 it is.
Expensive, but it sounds cool, so it must be better.

When you check your O2 filled tire pressure, I recommend something like a Bic lighter for illumination. Your tire pressure reading will be an explosive discovery. Since N2 is 78% of the atmosphere it can't be bad for you, I suggest you breath more of it.

Now the admins (with a lower case A) will have to split this off to split #2 :lol:

 

[MrZappo]

Still waiting on numbers. No need for 14 paragraphs on the subject.

It runs cooler? How much cooler?

Better gas mileage? How much?

It runs smoother? Sorry no.

You get more range on a tank? How much?

If more range, did it cost more for the fuel than the extra range is worth? How much more cash efficient is the expensive stuff?

Anyone ever heard of an engine failure due to running 87?

Anyone ever had an excellent gone last longer due to running 93?

 

[Old Guy]

A friend and I had virtually identical '02 Goldwings that got virtually identical fuel mileage. it was said that the 'wing would get better mileage on higher octanes, so we did a test. We filled up at the same time in Little Rock then did a weekend trip which involved freeway (I-40), slow two-lane (Nachez Trace) and state highways and freeways of Mississippi and Arkansas back home and filled up again at the same time. I used 87 octane for the entire trip; he used the highest octane he could find -- either 91 or 93. I don't remember the exact miles or fuel used, but in that entire weekend I used .01 (1/100) of a gallon more than he did.

 

[pista]

My understanding as well is that ethanol releases less energy than gasoline so in this case, hi-octane does produce more power.

Nope. Energy and octane are two completely different things.

While it is correct that the energy content ( btu's) in a gallon of gasoline is in fact higher than the amount of energy in a gallon of ethanol, there is no correlation between that and the octane rating of either one.

In fact ethanol has a much higher octane rating than gasoline yet has much less energy for any given volume.

Seriously, and perhaps to belabor the point, hi-octane in NO WAY produces more power.

Fun fact: To get an 87e10 blend of gasoline you usually start with 84 octane gasoline. The 10% ethanol blended in brings the octane up to 87.

 

[Redfish Hunter]

Since you guys seem to be winding down and I find you all hilarious...

My local AutoZone sells STP Octane Booster in a 12 ounce bottle for $6.99. I am thinking of buying a few bottles and shipping it to my dearest FJR forum friends. I think it would be money well spent.

According to the label:

Restores Performance

Made with Jet Fuel

Fights Knock and Ping due to Auto Ignition

Reduces need for High Octane Fuels

While it does not say so on the label, perhaps this will bring some happiness to those of you who seem so bitter.

 

[MajBach]

My understanding as well is that ethanol releases less energy than gasoline so in this case, hi-octane does produce more power.

Nope. Energy and octane are two completely different things.

While it is correct that the energy content ( btu's) in a gallon of gasoline is in fact higher than the amount of energy in a gallon of ethanol, there is no correlation between that and the octane rating of either one.

In fact ethanol has a much higher octane rating than gasoline yet has much less energy for any given volume.

Seriously, and perhaps to belabor the point, hi-octane in NO WAY produces more power.

Fun fact: To get an 87e10 blend of gasoline you usually start with 84 octane gasoline. The 10% ethanol blended in brings the octane up to 87.

I suppose you could have taken that context. What I was trying to say was, the higher octane gasoline (i.e. Shell V-Power) which has no ethanol in it has more energy per volume than it's lower octane counterpart, despite the fact it (the lower octane) contains octane boosting ethanol. In other words, octane aside, a gallon of gasoline releases more energy than a gallon of gasoline/ethanol mixture. I made the error of referring to zero ethanol gasoline as "high octane" (which in this example is just happens to be.

So again, no ethanol = more power.

https://zfacts.com/p/436.html

 

[RossKean]

If you are talking about more power as in more horsepower, then you are not correct. There is more ENERGY available per gallon in the non-ethanol fuel. You will necessarily consume more fuel to get the same horsepower.

 

[N4HHE]

In fact ethanol has a much higher octane rating than gasoline yet has much less energy for any given volume.
Seriously, and perhaps to belabor the point, hi-octane in NO WAY produces more power.

Except in the limited case where one is allowed to increase compression ratio. This is what seems to confuse John Q. Public, that high compression engines require higher octane ratings, and generally believed to produce more HP. Therefore wrongly assume high octane ratings are the source of more power.

After all everyone knows, "You get what you pay for" and high octane is called "premium" so it must be better, and it costs more which only proves it is better else no one would pay extra!

Few can change compression ratios to optimize available octane ratings. A Prius can, but a Prius will throw an engine fault code if fed a regular diet of 93 octane. It wants 87 octane.

 

[TripperMike]

Anyone ever heard of an engine failure due to running 87?

I may not be too bright when it comes to the inner workings of an engine, but how on earth can one look at a failed engine and pinpoint it's cause to the octane it was running?

 

[mcatrophy]

Anyone ever heard of an engine failure due to running 87?

I may not be too bright when it comes to the inner workings of an engine, but how on earth can one look at a failed engine and pinpoint its cause to the octane it was running?

By the burn holes in the piston? At least, that's what happened to one or two engines I saw where owners were "saving money" by buying lower octane fuel than their engines needed, and ignoring the pinking.

Probably the pre-ignition concentrates on specs of carbon on the top of the piston which began local melting, so the little blobs of aluminium would glow and cause pre-ignition in the same place. An example of a positive feedback mechanism giving rise to a runaway condition.

Edited to add that, if I remember correctly, there was usually excessive ovalling wear to the top of the cylinder due to the piston being rocked by the uneven burn.

 

[TripperMike]

Makes a lot of sense, thanks.

Now with that said, can anyone here say they have either seen, or heard of that ever happening to an FJR? I haven't.

 

[ionbeam]

To add on to Mcatrophy's post... The crank bearings and wrist pins & bearings can be damaged by the constant pounding as well.

 

[mcatrophy]

To add on to Mcatrophy's post... The crank bearings and wrist pins & bearings can be damaged by the constant pounding as well.

Yeah, but in my day you couldn't tell the cause of bearing failure. At least, not with my Tiger Cub, which seemed to run its bearings every 10000 or so for no particular reason.
Just as a heads up, in the UK the connecting rod bearings were always referred to as "little end" and "big end" bearings, the crank bearings as the "main bearings" or "mains".