HarleyTechTalk

Before Sunoco stopped producing 94 Ultra, it was my gasoline of choice. I'm fortunate
to have a variety of stations on the East coast that sell 93 octaine gas. I just wondering
if (in terms of engine performance) all 93 octaines are the same quality ? Lately, price
has played a big part of where I decide to fill up. Any brands you'd recommend not using?

  Using a higher rated octane gasoline than your motor requires will not give you any increased performance. The major reason for using the highest octane your particular engine setup requires is to prevent detonation, not to increase any volatility of the gas itself. The following is copied from another site and helps explain it better than I:                                                                                                                                                                           "If you've read How Engines Work, you know that almost all cars (and bikes) use four-stroke gasoline engines. One of the strokes is the compression stroke, where the engine compresses a cylinder-full of air and gas into a much smaller volume before igniting it with a spark plug. The amount of compression is called the compression ratio of the engine. A typical engine might have a compression ratio of 8-to-1.
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine (detonation). Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more."

I prefer the pumps that have 3 separate hoses and places where they allow you to pump before you pay. In our area most Turkey Hill stores are like that. If we stop somewhere they don't have high octane we buy a small bottle of octane booster and add it to the tank.  Our engine is really fussy and will ping on anything less than 92. I would gladly pay more for a true 94 octane.

  I run 93 in all the bikes,,,I try too avoid ethynol or methynol buts its gettin hard to avoid...I'm also not a big fan of fuel additives,,,booster,,rocket fuel ect,,,they contain tolulene,,,,not motor friendly
Dave

                   

       www.toptiergas.com

I've read it in several different forums and not neccessarily MC ones.  Basically it comes down to; the different gasoline brands are not separated anywhere but at the store. More than likely the 91oct at Standard is the same as at 7-11 is the same as at BP, etc, etc.  Any additives like techron or cleaners, etc. are added at the store or the facility if the whole tanker is going to one place.  Even the oil coming out of the ground is mixed from one company to another, the only thing they keep track of is how much they pump out of the ground.  After that all the oil gets sorted according to grade.

So find the best price with the additives you like and ride.

   

I run regular with no problems, no pinging, good gas mileage. 

"I run regular with no problems, no pinging, good gas mileage."


We also have a little Buell Blast that will run either as well, but with Premium  gets about 60 mpg and with regular it drops down to about 55 so I keep buying premium for that one as well.

On edit:

boooby1744,

I looked at your link and also looked at the retailer and saw they
listed Turkey Hill Minit Markets, which I wrote about previously. I hate to
say one station is better than another but have occasionally told people
it seems like the Harley does a little better with premium from Turkey Hill.

I generally use mid-grade (89) with no problems in a close-to-stock TC. Occasionally I am forced to Regular (86/87?) which runs OK if the bike isn't under stress.. pings if it is.
With all the additives the manufacturers put into gas these days. as well as ethanol and so forth, what effect does it have on our carbs and FI systems?

I would guess that this(top Tier gas) is the reason Harly has teamed up with "Shell Gas"??
Dan

 

Doubt that - I'd be surprised if that wasn't a pure marketing decision - I'll scratch your back, you scratch mine...


I do have one question for those more into chemistry than I - Shell's been advertising "nitrogen added" - last I knew nitrogen was an inert (doesn't react with anything) gas.  Makes up 79% of what we breath & causes concern when I scuba dive because of potential bubbles - don't think bubbles in gasoline would be a good thing either    Seriously, anybody got info on what this does beyond the marketing hype?

-bogie

I have an 03 Ultra. stock except for H-D touring mufflers and Stage 1 air filter kit. I have been using 87 regular since day one even on all my previous bikes. Also used 87 in my Vettes, except on track days when I want the full monty. If I'll be in the mountains with the bike I'll usually put in premium, but on the super slab it gets nothing but 87. Never had any engine problems.
Like dunbarton said, a little pinging if under stress, so I don't put it under stress.

Shells nitrogen enriched gasoline will not give you better performance (more power).  The nitrogen is part of the detergent package.  The nitrogen molecule (N2) is added to the detergent to prevent the detergent from being burned up under high heat/load conditions.  With more of the detergent not being burned off, the engine is cleaned of carbon build up more effectively.  As was mentioned nitrogen is an inert gas and will not burn so there is no added power when the gasoline is ignited.

-Craig

I use 87 in my '06 Dyna, 95", Flat tops, SE204, SE air, .030 HG with no problem running on the flats and highways. If loaded and two up or going mountain climbing I'll used the high octane. (or planning to hot rod it!!)
Dan

Shell also advertises 'V-Power" gasoline.  Do ya think the gasoline can tell whether it's in a V or in line configuration and perform accordingly?

I am not a chemist but did spend 15 years making gasoline.  Just how would they combine N2 molecules to a hydrocarbon liquid?

PC

Your guess is as good as mine.  From what I read (not a Shell advertisement) the N2 molecules are attached to the detergent additive to stabalize it.  They report that this keeps the detergent from being burned off as quickly under high heat/load conditions resulting in better cleaning.  No claims that is does anything other then help the cleaning process.

-Craig

Can't say this with any certainty, Craig, but kinda sounds like most other advertising malarkey.  The additives I put in gasoline were pretty stable to begin with from outward appearances.  Wonder how the N2 molecule was attached?

PC

I think most detergents contain Nitrogen. Why when dishsoap is applied to a lawn it turns almost blue.
"Nitrogen enriched", nothing scientific, more marketing BS IMO.

Ummmm, move to the UK where you can run your Harley on 99 octane straight out the pump at all supermarket filling stations like i do ! On second thoughts, maybe its not such a good idea to move here......

Mind you, 99 octane DOES make them go 

Dang it now you all done gone and screwed up my extra HP, Figured using V2 gas was better for the Vtwin....

99 octane DOES make them go 

Ya mean 99 octane makes them faster?

PC

I've never seen octane make anything faster.

-Craig

Quote from: Bruno-Katz Fokkerpilot on July 24, 2009, 06:22:17 AM
Ummmm, move to the UK where you can run your Harley on 99 octane straight out the pump at all supermarket filling stations like i do

Are you aware that there are different octane rating methods?
The method used in the US is very likely not the same as commonly in Europe.  If I remember correctly, the difference in numbers between the two most commonly used methods is around 10.  So your 99 may be approximately the same as our 89.

Research Octane Number (RON)
The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.

Motor Octane Number (MON)
There is another type of octane rating, called Motor Octane Number (MON), or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load as it is done at 900 rpm instead of the 600 rpm of the RON[2][3]. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally, fuel specifications require both a minimum RON and a minimum MON.

Anti-Knock Index (AKI)
In most countries, including all of those of Europe, and Australia, the "headline" octane rating shown on the pump is the RON - but in the United States, Canada, and some other countries,[which?] the headline number is the average of the RON and the MON, called the Anti-Knock Index (AKI). It may also sometimes be called the Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2.

Difference between RON and AKI
Because of the 8 to 10 point difference noted above, the octane rating shown in the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel. See the table in the following section for a comparison.

I'm not capable of discussing this at the level some of you are, but in very basic & simplistic terms, the higher the octane rating the less flammable the gas is.

higher octane and the resulting lower flammability allows higher compression & more ignition advance because the fuel is less likely to ignite under the sheer compression (like a diesel does) and helps slow down and even out the flame spread in the cylinder. in essence, the fuel becomes less explosive in that highly compressed enviornment.

Please smart guys, tell me how far I'm off on this, I am always willing to learn!