Gas ⛽️

[G-922407]

Don't understand people complaining about $5.00 - $7.00 more per tankful for premium. Are these people that broke? I have never bought regular, really never owned anything that would qualify for low-octane fuel. To each his own I guess. If you ever refined fuel for a living you would realize that regardless of brand, higher octane fuel is a higher refined product. For lack of a better description it is boiled higher in the tower and is more pure. So buy whatever. Personally I would have not and never will own a cheap ass car that runs on regular.

 

[Slip_Angle]

I use the octane level that optimizes performance. Not an arbitrary choice but actual testing. The quality of gas is not defined by octane levels. For example, If I take 93 octane fuel and add boostane, the fuel quality doesn't change. In my actual testing with my G70 3.3T in moderate ambient temperatures, 87 octane performs the best. Lower octane has a faster burn rate. Now, if I lived in Texas I'm sure my results would be different. Higher ambient temps would likely result in the need for higher octane to prevent knock and ignition retard.

 

[exbimmer]

Someone knows that you are throwing your money away, but at least you are wise enough to do it at Costco with Top Tier gas.

I got trigger happy please see below:

 

[exbimmer]

Found this an interesting article:

AAA: Not All Gasoline Created Equal

Tests show quality gasoline keeps engines 19 times cleaner

newsroom.aaa.com

 

[EdP]

Found this an interesting article:

AAA: Not All Gasoline Created Equal

Tests show quality gasoline keeps engines 19 times cleaner

newsroom.aaa.com

I think most of us here agree that Top Tier is better than the generics. What is still controversial is regular vs premium when premium is not called for and is Brand X better than Brand Y if they are both Top Tier.

There are many opinions but little real fact.

 

[exbimmer]

I don't know much about cars' engines.... But doesn't lean and cleaner better better gas make performance? So wouldn't it be good to buy the highest quality of gasoline? I don't know.....

 

[Slip_Angle]

I think most of us here agree that Top Tier is better than the generics. What is still controversial is regular vs premium when premium is not called for and is Brand X better than Brand Y if they are both Top Tier.

There are many opinions but little real fact.

Premium is a higher octane fuel. Higher octane resists engine knock better but burns slower/releases less energy thus producing less power at a given ignition timing level.

 

[EdP]

I don't know much about cars' engines.... But doesn't lean and cleaner better better gas make performance? So wouldn't it be good to buy the highest quality of gasoline? I don't know.....

Sure, that is where Top Tier comes in. They have an additive package that meets the needs of today's engines to burn cleaner.
You say highest quality gas. That is where the controversy comes in. Both regular and premium are made to meet specification by the government. Some engines need premium, others do not but quality wise, both are equal.

Now you get down to the brands of gas. Have you ever seen the big tank farms that feed the regional gas stations? They have two types, premium and regular. It does not matter who refined it, it is the same be it Arco, Exxon, Shell, etc. The tank truck goes in, fills up with regular. Now, he goes to another tank and this is what makes a difference. He puts in the additive package. If he is going to deliver to Shell, he puts in the Shell additives, if he is delivering to Exxon, he puts in their additives. Since they are both Top Tier, it may even be the same package.
If he is delivering to Bob's Discount Gas, he may put in a lower priced package that would make a lower quality gas.

I only use Top Tier but brand does not matter. I mostly use Shell because it is convenient and if I use their credit car I get 5 cents a gallon discount. When travelling I use others and cannot tell any difference.

 

[carguy75]

Brand preferences aside, just use top tier gas and the engine will be fine. I personally did noticed subtle differences in how my engine runs with certain brand gas blends, but all and all the top tier brands still provides the clean fuel the engine needs regardless of the blend of chemical used.

Just pick a top tier gas brand and roll with it.

 

[Slip_Angle]

I recently watched a comprehensive test of several brands and even though they were all top tier, they were very different in terms of performance.

Sorta, kinda surprised me...

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[EdP]

I recently watched a comprehensive test of several brands and even though they were all top tier, they were very different in terms of performance.

Sorta, kinda surprised me...

What sort of testing did they do?

 

[Slip_Angle]

What sort of testing did they do?

It was done in Vancouver Canada. Testing several brands of Canadian and a couple American fuels, I believe. Brand and octane comparisons. It was really interesting. Shell 91 is Canada appears to be absolutely terrible in terms of knock and ignition retard, resulting in a substantial power decrease. It's a 3 part series and really worth watching.

Here is part 1...

 

[carguy75]

It was done in Vancouver Canada. Testing several brands of Canadian and a couple American fuels, I believe. Brand and octane comparisons. It was really interesting. Shell 91 is Canada appears to be absolutely terrible in terms of knock and ignition retard, resulting in a substantial power decrease. It's a 3 part series and really worth watching.

Here is part 1...

I watched part 3 and it does make sense that a 94 octane fuel will make more power than a 91 octane fuel in a high compression engine or forced induction engine. If the 91 Shell made more power than the 94 octane Chevron than I would have been impressed with the results.

Is Shell 91 considered premium grade fuel in Canada? I would assume that Shell has a 94 octane version as well like Chevron. That would have been a better comparison test.

Furthermore, ethanol does gives fuels a boost in performance in high compression/force induction engines; so the ethanol-free 91 Shell would be weak in terms of high performance fuel in a turbo performance engine compared to the ethanol-blend 94 fuel.

 

[PMCErnie]

The bottom line is that tests like this are never going to prove that Canadian beer is superior.

 

[Trixie86]

The bottom line is that tests like this are never going to prove that Canadian beer is superior.

Damn, always thought Moosehead was the "nectar of the Gods" when I was a kid.

 

[EdP]

It was done in Vancouver Canada. Testing several brands of Canadian and a couple American fuels, I believe. Brand and octane comparisons. It was really interesting. Shell 91 is Canada appears to be absolutely terrible in terms of knock and ignition retard, resulting in a substantial power decrease. It's a 3 part series and really worth watching.

Here is part 1...

Interesting. I wonder how Canadian standards differ from US or even BC area from the rest of Canada.
Of course, this is only one element of what makes the "best" gas. Sure, power is important and it looks like the test is done on a pretty equal basis. What is not determined, what to the valves look like after thousands of miles? Is there a trade off between power and clean engine? Does the gas with the most power run as smooth at idle and start in temperature extremes?

Both the Shell and Esso seem to suck. I have to wonder if they are the same gas out of the same tank at the tank farm. He certainly made a good try to verify it was not a bad batch from the first station. That is a huge HP difference.

My priority would be for a cleaner engine over 3 horsepower if it came down to that. At least he tested Top Tier vs Top Tier so there should be little difference over the miles.

 

[Slip_Angle]

I watched part 3 and it does make sense that a 94 octane fuel will make more power than a 91 octane fuel in a high compression engine or forced induction engine. If the 91 Shell made more power than the 94 octane Chevron than I would have been impressed with the results.

Is Shell 91 considered premium grade fuel in Canada? I would assume that Shell has a 94 octane version as well like Chevron. That would have been a better comparison test.

Furthermore, ethanol does gives fuels a boost in performance in high compression/force induction engines; so the ethanol-free 91 Shell would be weak in terms of high performance fuel in a turbo performance engine compared to the ethanol-blend 94 fuel.

Watch all three videos in order. The primary point was to see how the stock car performs with different brands. The octane comparison was secondary. His Audi S4 requires 91 octane or better. That means in theory the car should deliver the advertised power using 91 octane. With Shell 91 the ECU needs to retard timing significantly and the result is that the car is way down on power. In theory, an engine should perform best with the minimum octane that does not reduce timing due to knock. So with a stock ECU, 91 and 94 should perform roughly the same (91 may be slightly better) *if* the ECU caps ignition timing to meet performance specifications. This is because the higher the octane fuel the slower the burn and energy release. (assuming the ECU doesn't adjust timing to further increase power).

 

[Slip_Angle]

Interesting. I wonder how Canadian standards differ from US or even BC area from the rest of Canada.
Of course, this is only one element of what makes the "best" gas. Sure, power is important and it looks like the test is done on a pretty equal basis. What is not determined, what to the valves look like after thousands of miles? Is there a trade off between power and clean engine? Does the gas with the most power run as smooth at idle and start in temperature extremes?

Both the Shell and Esso seem to suck. I have to wonder if they are the same gas out of the same tank at the tank farm. He certainly made a good try to verify it was not a bad batch from the first station. That is a huge HP difference.

My priority would be for a cleaner engine over 3 horsepower if it came down to that. At least he tested Top Tier vs Top Tier so there should be little difference over the miles.

I would agree with the exception that Shell 91 was causing a lot of knock (even audible), causing ignition timing to be reduced by up to 8 degrees and a 40hp decrease, which is stunningly terrible and may over time cause worse engine issues then any sort of build up...

 

[carguy75]

Watch all three videos in order. The primary point was to see how the stock car performs with different brands. The octane comparison was secondary. His Audi S4 requires 91 octane or better. That means in theory the car should deliver the advertised power using 91 octane. With Shell 91 the ECU needs to retard timing significantly and the result is that the car is way down on power. In theory, an engine should perform best with the minimum octane that does not reduce timing due to knock. So with a stock ECU, 91 and 94 should perform roughly the same (91 may be slightly better) *if* the ECU caps ignition timing to meet performance specifications. This is because the higher the octane fuel the slower the burn and energy release. (assuming the ECU doesn't adjust timing to further increase power).

My point exactly. The S4 owner engine requires 91 or better fuel. His engine gained more power with 94 octane as expected. Modern engines usually reduce timing as the rpms increase past a point or at WOT especially force inducted engines, so it may not be a fuel quality issue; but just how the engine runs normally. However, higher octane reduces the need for reduced engine retard as the rpm increases; hence again why 94 octane created more power.

91 or better, means the engine runs better as the octane increases as was the case for the S4 owner dyno results.

However, it does seem like Shell 91 is probably not a true 91 octane fuel based on the results. Hell, my engine runs a bit weaker with Shell 93 octane compared to BP or Chevron 93 so it may be a Shell thing; cleaner burning I suppose but at the cost of performance. My engine run smoother with Shell for whatever reason, probable due to run less aggressive timing.

 

[TinsleyC]

I don't know much about cars' engines.... But doesn't lean and cleaner better better gas make performance? So wouldn't it be good to buy the highest quality of gasoline? I don't know.....

While that's all true, just don't make the mistake of assuming that higher priced gas is better. Octane costs more, and higher octane prevents early detonation in a high compression engine. Octane needs are based on engine needs, and octane level has no bearing on quality. It's the additives that define gas quality.

Now, of course we're assuming the gas is stored correctly, not contaminated, and made properly. But as EdP pointed out, one tanker will fill an Exxon, Shell, or Mobil station - it's a commodity.