Arco,Shell, Exxon different?

[Kev m]

Interesting claim...you have proof ? 

Other than it being taught in tech school, listed in multiple repair manuals, and the base logic (octane = resistance to combustion, and too much resistance to combustion = more unburnt materials)?

I used to have a go to link from a Canadian TV station that did back-to-back testing on a run of the mill sedan (maybe GM product). It was a 20 minute or so segment where they drained the tank, filled it with premium, ran it a bit to allow trim to set, then put it on a dyno and pipe sniffer. The repeated the test with regular. The dyno/exhaust test operator was surprised at the results, higher emissions on the premium.

To be clear this was a mile compression, naturally aspirated motor that was spec'd for "regular" octane fuel. Obviously results could differ with other vehicles, but I think it spoke to the theory well.

Ahh, found it, it's on YouTube now, I think it used to be on the TV station's link.

https://www.youtube.com/watch?v=FPPkPAbzwbU


Now granted, this doesn't talk about the deposits, but as we know, more unburnt HCs means more deposits.

[Rough Edge racing]

Other than it being taught in tech school, listed in multiple repair manuals, and the base logic (octane = resistance to combustion, and too much resistance to combustion = more unburnt materials)?


Now granted, this doesn't talk about the deposits, but as we know, more unburnt HCs means more deposits.

 This is a often debated topic on racing forums...Higher octane is not an overall resistance to burning, the higher octane prevents premature combustion of the end gasses in the combustion chamber that causes detonation... This is exactly what tetra ethyl lead  does...However I don't have knowledge if the anti knock ingredients in unleaded pump gas function exactly the same..
 

[sign216]

I talked with the driver of a fuel tanker truck in Massachusetts.  His truck caught my eye when I saw the truck had changeable placards for the brand of fuel he had.  Driver said the distributer uses the same base fuel for every brand, but that every brand has an different additive package.  If he's making Shell deliverys, the truck get's the Shell additives and then puts up the Shell placard.  So on for other brands.  Driver said one brand (I forget which) use their only their own trucks, but other share the same similar trucking services.
 

[cookiemech]

I talked with the driver of a fuel tanker truck in Massachusetts.  His truck caught my eye when I saw the truck had changeable placards for the brand of fuel he had.  Driver said the distributer uses the same base fuel for every brand, but that every brand has an different additive package.  If he's making Shell deliverys, the truck get's the Shell additives and then puts up the Shell placard.  So on for other brands.  Driver said one brand (I forget which) use their only their own trucks, but other share the same similar trucking services.

Wow! I guess in Mass they actually CARE what customers think they're getting when they buy a particular brand. It stands to reason that all gasoline in a particular area comes from the same pipeline . . . and it is my understanding from a number of articles I've read that they just add a different package for each retailer.

Here in western PA there are mostly nondescript tankers delivering fuel to each station, regardless of brand, EXCEPT for GetGo (Giant Eagle supermarket affiliate) and Sheetz (privately held chain). Neither, of course, is Top Tier.

[Rough Edge racing]

 Kev. I looked at the video and it's seems accurate once past the  "you're getting screwed as a consumer " theme... The owners manual of my 97 Jeep says the same thing." The engine will perform properly on 87 octane and only use a higher grade if it pings..."
  None of this applies to vehicles recommended by the manufacturer to run on higher octane fuel...like many newer sporty cars...And some not so sporty...

[sign216]

Wow! I guess in Mass they actually CARE what customers think they're getting when they buy a particular brand. It stands to reason that all gasoline in a particular area comes from the same pipeline . . . and it is my understanding from a number of articles I've read that they just add a different package for each retailer.

Here in western PA there are mostly nondescript tankers delivering fuel to each station, regardless of brand, EXCEPT for GetGo (Giant Eagle supermarket affiliate) and Sheetz (privately held chain). Neither, of course, is Top Tier.

Cookie, I was impressed that different brands actually had different additive packs. 

[Kev m]

Kev. I looked at the video and it's seems accurate once past the  "you're getting screwed as a consumer " theme... The owners manual of my 97 Jeep says the same thing." The engine will perform properly on 87 octane and only use a higher grade if it pings..."
  None of this applies to vehicles recommended by the manufacturer to run on higher octane fuel...like many newer sporty cars...And some not so sporty...

Sure, I guess everything needs a hook right lol.

But agreed.

And shy of pinging from too low an octane, I suspect most of us worry more than we need to about the RCHs of all these things - oil, fuel, etc.

[rboe]

Water should not impede ignition in the cylinder unless you have a ton of it. But water has a very high work function, meaning it absorbs a lot of heat before changing phases. Not sure about today but high performance engines in WWII used water injection during high boost to control the excess heat generated  by all the excitement of battle (and boost....).

I would think water in the gas, for us poor schleps motoring around town, will be a problem when it freezes in the gas line causing starvation, not well mixed so you get too much water going through the injectors messing with the proper fuel air mixture and robbing heat in the combustion chamber during the burn which would reduce power.

If one could keep the fuel water mixture nice and stirred up so you didn't end up with "clumps" of water going through the injection system I bet many problems would go away until the fuel water ratio got really out of hand. I have no idea what level that would be at. Just brain storming here.

If memory serves, lead was also added to lube the valve train in some older motors. Some designs had to use clever designs to deal with excess lead deposits (memory is very blurred on this as I read an article in Wooden Boat over 25 years ago as boaters were very concerned about the new lead free gas and what it would do to old boat motors - it appears lead free was better for them). The aviation industry is going through the same hand wringing now.

I'll go back to wondering where the tinging is coming from. 

[rocker59]

Water should not impede ignition in the cylinder unless you have a ton of it. But water has a very high work function, meaning it absorbs a lot of heat before changing phases. Not sure about today but high performance engines in WWII used water injection during high boost to control the excess heat generated  by all the excitement of battle (and boost....).

 

Water Injection Systems were also popular in the Auto Aftermarket in the 1970s and 1980s to help owners deal with pinging.

A quick internet search shows Summit and Jegs still sell them for the drag racers...

[Kev m]

Well both those comments sorta agree that water in the fuel isn't going to CAUSE pinging and overheating. Yes?

[rocker59]

Well both those comments sorta agree that water in the fuel isn't going to CAUSE pinging and overheating. Yes?

Water in fuel cools the the charge and reduces pinging/pre-ignition knock...

The water injection systems use a water/methanol mixture.

The injection systems are controlled, though.  Leaving E10 gasoline sitting around absorbing moisture would probably allow it to absorb more than is good, and would rather likely be bad for power and corrosion...

[normzone]

[rocker59], that link goes to a page in limbo, apparently.

Back in the olden days, I saw water injection on turbocharged engines and alcohol/water vapor injection (vacuum insertion, actually) on naturally aspirated engines as a mileage enhancer. Results varied on the latter ...

[Air-Cooled]

My experience echoes Kev's remarks. I used to use the highest octane levels in my carbureted bike and was constantly replacing the pilot jet due to clogging. Have not had a problem with the lower octane levels (Honda XR600R). I use 87 in cooler weather and I don't get pinging/detonation. In the summer I have to go up to 89. A kick start bike can be a real pain if you're pilot jet is too lean.

[rocker59]

[rocker59], that link goes to a page in limbo, apparently.
 

Wiki must have hot-linking disabled.  The article is there, if you search "Water Injection"

[oldbike54]

 It might be good to remember that the octane rating system in place now gives lower ratings than the method used when the Alfa was built . Modern 91 octane equals 96 octane from then . I am curious about the overall health of the Alfa engine . Carbon buildup in the combustion chamber will cause an engine to ping , as will some other factors . Has the engine been apart and rebuilt since the advent of modern unleaded fuels ? What is the static compression ratio , and has that been checked against spec ?

 Dusty

[rocker59]

It might be good to remember that the octane rating system in place now gives lower ratings than the method used when the Alfa was built . Modern 91 octane equals 96 octane from then . I am curious about the overall health of the Alfa engine . Carbon buildup in the combustion chamber will cause an engine to ping , as will some other factors . Has the engine been apart and rebuilt since the advent of modern unleaded fuels ? What is the static compression ratio , and has that been checked against spec ?

 Dusty

Something tells me HAZE is in Europe and pumping 95 RON into his '67 Alfa.

In North America, it would be (95 RON + 85 MON)/2.  Or, 90 at our pumps.

[oldbike54]

Something tells me HAZE is in Europe and pumping 95 RON into his '67 Alfa.

In North America, it would be (95 RON + 85 MON)/2.  Or, 90 at our pumps.

 He is in Pennsylvania .

 Dusty

[Rough Edge racing]

My experience echoes Kev's remarks. I used to use the highest octane levels in my carbureted bike and was constantly replacing the pilot jet due to clogging. Have not had a problem with the lower octane levels (Honda XR600R). I use 87 in cooler weather and I don't get pinging/detonation. In the summer I have to go up to 89. A kick start bike can be a real pain if you're pilot jet is too lean.

  I believe Kev info meant combustion chamber deposits... Many of us run higher octane fuel and don't have carburetor deposit issues..

[Arizona Wayne]

If your motor is designed for 87 octane gas and you put in higher octane you are wasting your gas $.   Fuel injected motors with 02 sensor are designed to adjust the timing of ignition to whatever the gas/altitude combination is best for efficient combustion.

[sdhow]

Here in western PA there are mostly nondescript tankers delivering fuel to each station, regardless of brand, EXCEPT for GetGo (Giant Eagle supermarket affiliate) and Sheetz (privately held chain). Neither, of course, is Top Tier.

What about this place?:





Any idea what kind of additives are in their "package"???

[Arizona Wayne]

What about this place?:





Any idea what kind of additives are in their "package"???

Yuck, that additive is too sticky to put in MY motors.