:rukidding: people still believe this shit? Its common sense man. Unless you tune your car for a different Octane nothing will change. If you put a different octane in your tank when your air and fuel mix and get compressed it could combust earlier or later then its supposed to.

Lets say you run 89 fuel on a car that requires 91, the adaptation gets set to -4 over a few hours. In 4 months time, you decide to switch back to 91, how does the engine decide when to change the adaptation back to 0 instead of pre-applying the value?

Results are in
got 465km on the tank
usually I get 425 with 87, when I pumped it clicked at 59.xxxL so there was 1 litre away.

Not sure if its worth the extra $7

^
Did your driving route change, by chance? i.e. any highway driving more than usual?

The weather is slowly getting warmer too but that shouldn't make that huge of a difference.

ECU's are always adjusting values to run at optimal efficiency. They do this by intentionally varying actual ignition/injection values by a small amount away from "normal" and monitoring sensors to see the results, and, if necessary, further adjusting adaptations. In fact, adaptations are always being adjusted over the life of the vehicle, usually only by very small amounts.

That said, an engine can adapt very quickly to lower octane fuel because knock will occur far more often. Switching to higher octane would take longer to adjust adaptations simply because there's no "immediate" change that the ECU would see.

Another example of this (though not related to adaptations) is an oxygen sensor response test. The ECU would intentionally make the mixture richer by increasing injector pulse width and then monitoring how long it takes for the oxygen sensor to respond. A good sensor should respond very quickly (perhaps 100ms) while a bad sensor might take much longer (600ms or more). If the sensor takes too long, you will get a check engine light and a code that says something like "O2 Sensor Aged" or "O2 Sensor Dynamic Response".

Stayed routine

My Jay-Dee-M vehicle is mapped for 98 RON gasoline which is about 94-95 Octane reading here... so I'm pretty much stuck on 94 Chevron. Tried 91 with Shell before but I noticed the mileage went down a bit.

I've been using 94 octane ever since I bought my car.

Here is my car's fuel recommendation

Will switching back to 87 octane mess up the timing?

And what would the bold line mean? Is ethanol considered detergent additive?

Anyone see this? Found it kinda interesting but wished they did a long term run.

http://www.cbc.ca/marketplace/episod...mpfiction.html

Chevron 91 has any ethanol mix?

I noticed my car runs better on Canadian Chevron 91 compared to Pt. Roberts Chevron 92.

Correct me if I'm wrong, but Shell V-Power now has ethanol, unless the pump specifically states no ethanol...

Anyways, I use Chevron 94. I get about 340-360 km out of a 70L tank... All city driving.

Saw that the other day. Though they are essentially correct in stating it's a waste putting higher octane gas than what your vehicle recommends, some of their test methods are seriously flawed.

For example, when the mechanic had the vehicle hooked up to a gas analyzer to monitor the exhaust emissions. Anyone who has ever used an analyzer (like trying to get cars to pass Aircare) knows that readings change even from minute to minute. There's no way you could drive a car on one tank of 87 octane, measure the readings, and then drive on a tank of premium and measure the readings again, and get any kind of meaningful result that you could attribute to the different gas. Even a difference in the weather from one day to the next could affect readings. Or the engine temperature (how long did the vehicle run before each test). Or the adaptations (which have been discussed already).

Gas analyzers are only really useful for measuring large changes or to monitor changes while you're specifically changing something (like adjusting a carb). They are absolutely useless as any form of data gathering device.

Has anyone gone to Aircare and failed then gone back and passed? That tells you right there how accurate gas analyzers are.

Dayum, what car do you drive??

I guess it's not THAT big of a deal with 94 vs 87. The difference in like approximately $7 more and it's a peace of mind knowing I'm running on non-ethanol fuel.

BMW M6

so cocky and proud :troll:

lol my car calls for premium unleaded =.= i use both chevron 94 i get 300km but when i use shell 91 no ethanol i get 350 on a 50L tank =.= so im :fulloffuck:

I used to drive a 2000 Nissan Maxima, It was reccomended to use 91, I used 87 for a month or two, I averaged 14.3 l/100km, I used 91 like it said to, I averaged 11.2 l/100km. So yes, You WILL hurt fuel economy by using a lesser octane than you should be. Higher octane than reccomended IS a waste of money however.

I actually had this issue happen. Kept getting "O2 Sensor Slow Response" CEL. Eventually, I changed the O2 sensor, and noticed that I was getting better gas millage.

LOL the instructor running the dyno at the Canadian Auto & Trucking College thought that it would make a difference, what a shitty teacher.

And asking the gas pumpers what is cleaner? Who does CBC think they are, Fuel Sommeliers? It's not like they go through a rigorous product training course before they start working, what would they know?

Whole video is pretty misleading to the general public to say the least.

It's amazing how someone will trust someone making minimum wage at a gas station over what the manufacture recommends.

Quality is not measured by octane. Those lines simply means don't buy gas from shady dudes from the back of their van.

Ethanol is not a detergent additive; it is an octane booster.

10% ethanol blend equates to roughly 3 points increase in octane. So, the 87 w/ 10% ethanol @ Chevron is actually more like 84-86 + ~3 octane from the ethanol.

Companies like Chevron, Shell, and Petro Canada are all what are referred to as "top-tier" distributors. This means that the gas that they sell is guaranteed to meet the minimum required qualities and detergent levels mandated by the EPA.
Generally speaking you're getting much more than EPA standards for detergents in your gasoline, for example, Shell's V power simply means that there are 5x the mandated amount of detergents. The mandated amount of detergents does NOT clean the engine, it only prevents more build up.
87 to 94, they all come from the same fuel farm, same pipeline. The differences between them is the amount of octane boosters blended in prior to distribution; this is also where each company blends in their additives.

Problems with alcohols:
-hydroscopic (absorbs water)
-fixed volatility (each molecule is the same size and configuration. meaning they volatize at the same temperature. gas is comprised of many different sized hydrocarbons. Light ends (short chains) are the molecules that evaporate first (good for cold starting), heavy ends are the ones that contain the most energy.
-less energy per unit compared to gasoline
-removes oil from the combustion chambers of 2 stroke motors =(


Oh PS, that 87 octane you bought from Chevron? Ya, that's more like 89 octane. The octane rating at the pump is a LEGAL MINIMUM, so they're always higher than advertised.

:troll:

It is said that ethanol is the culprit of engine knocking sounds, like someone through screws into the piston chambers.

Is this true?

Overall, is ethanol good for your engine? Or does it damage it over time?

Those BMW drivers......






:troll:

Ethanol increases octane, reduces detonation.

@ current 10% blends and at near future 15% blends, your not doing anything detrimental to your car. Higher blends will start to be corrosive to the plastic/rubber parts of fuel systems in older cars. Most affected will be the 2-strokes n rotaries.