Originally Posted by Soliditude

From multiple BMW drivers who used less-than-premium fuel for a while. Messes something up, gives sensors the wrong reading, and overtime, your cats go. I'm not a mechanic, so I don't know how it works, but I personally know people who did that and then said, "damn, I wish I stuck to premium." It might not be the same with our G's, but still. Factually, using less-than-premium in a car that requires premium does no good.

Originally Posted by CateyeRR

Gas is gas.

Originally Posted by adroitcaptor

There is a lot of wrong, unsupported, and plain fabricated information in this thread. (There is also some accurate information…) Please do not rage on me until you try and understand what I am saying in this post from an objective standpoint. I am NOT flaming anyone NOR is any part of this post aimed at anyone specific!

Because different stations use different services with different additives at different times, it is near impossible to delineate REAL differences of brand gasoline(s). That said there are some stations that are much more consistent than others.

Before you go buying additives look at the cost of racing fuel/aero grade fuel and do some math. If you need help or further explanation I would be happy to give it. Suffice it to say, MOST additives, unless used solely as a detergent, are a rip off.

There is no more "power" in one fuel from another, so to say. I will steer clear from giving a lecture on iso-octane and the comparative RON (rating system). HOWEVER the caveat is in the semantics. The ‘raw’ fuel itself has no more ‘power’. In fact, this myth of one fuel burning ‘faster’ or more ‘powerful’ is an absurdity. The difference that you are seeing is the fuel’s resistance to engine-knock (pre/self-ignition). In a very basic explanation, the higher the octane the higher pressure the fuel can be compressed to before it ‘self-ignites’. Anyone who understands turbo systems must have a strong grasp on this concept (or follow it unknowingly). There is one major deviation from this “fuel is fuel” explanation. That is the additives a company/refinery will/might put in the fuel. THIS INCLUDES, but is obviously not limited to, ethanol. When we consider these bastard excuses for profit and EPA mindless communism, we start seeing a difference in ‘energy’ output / (specified) volume of fuel. Methanol has less than half of gasoline’s specific energy / energy by raw volume; ethanol is generally about one third. SO the 91octane of America (with 10% ethanol) has less energy by volume then Europe’s 91octane (with 3%). Where these numbers are not PftA , they are not exact, that would require a lecture style post... lol

I would argue, and could support, that additives DO matter. (To what degree is quite another issue.) What is more concerning to me is how the gas is kept, transported, and refined. If you want to argue that a person can go to 5 different stations and all the 5 petrol samples will be the same, I will point out you do not have a grasp on the reality of this subject.

Many made the point that the same truck will go to the two different places. Where they might receive the same gasoline this assumption cannot always be concluded. The obvious point being - a single truck can provide more than 1 RON type of fuel.

Subjective evidence is just that. People, let us not go around making rash judgments, statements, or even postulations based on a one time, uncontrolled experience. Right as we may be, it is absurd to pose knowledge based on this type of lazy behavior. I always maintained [on other car forums] that if you do not KNOW give an opinion stated as an opinion; if you KNOW help others to understand from fact.

Bottom line, there are many factors that contribute to knock. Do not think that running a higher octane will get you ‘more power’. Once the limitations of timing (not considering mods or dyno tuning) have been reached, there is ‘nothing’ more to gain by higher grade fuel. The antithesis of this is also true – once your vehicle’s timing has compensated to its limit, a lower grade fuel will reduce performance.

I hope this helps people to understand some of the ‘science’ of this issue. If you would like clarification, think I am full of it, or simply want more information, let me know; I would be happy to help/respond.

Originally Posted by ANMVQ

Is to me, I dont think I get anymore WHP or at least anything I notice, But just use it to keep everything clean. I ran a test a few years ago with this stuff(15 years ago) Where a ran 93 oct same station for 8 week. Took the carb and intake off and looked at the ports. They where a little and had some build up on them. Cleaned them off put it back on and ran 8 more weeks and used this stuff 4 times( Twice a month).. Took the intake off again I could have eating of it. Since then still using it. Only thing is only two places sell it near me. So I always get 5 bottles 2 for myself,2 for the wifes G and one for her bike( Smaller bottle 16 ounces).

Originally Posted by irrelevant

Thanks for posting something of value. I'll expand a little further on one of your points.

Trucks that deliver fuel have multiple compartments to deliver from. From my experience, as the owner of a gas station myself, these compartments will hold 3400 gallons, 2700 gallons, 1800 gallons, and 1100 gallons - for a total of 9,000 gallons.

There are times when I order 87 octane, 93 octane, and diesel fuel all delivered by the same truck.

Why 9,000 gallons? There are a couple of reasons. One is the gross weight of the truck when full of fuel is very close to the maximum the D.O.T. allows a truck to weigh.

Another is the capacity of the underground storage tanks (UST's). Mine are 10,000 gallons each - of which 10% is reserved for expansion. Basically I can only fit 9,000 gallons of fuel in a 10,000 gallon tank.

I could write a book on gas station operation, why different stations appear to give more or less gas mileage, and why different pumps dispense more or less than the amount of gas you see displayed on the meter (yes, they're inspected annually...but there are tolerances the pumps can operate within and still pass inspection). Honestly though, you guys and girls are participating on a forum devoted to late model, high performance vehicles with current values from $25k - $45k, so further discussion of the miniscule differences in gas mileage delivered from brand to brand and station to station is, in my opinion, infinitely pointless.

If you're obsessing about gas mileage to this degree, please do yourself a favor and trade your G in for a Prius. If you're participating because you really want to put the best into your car, that's fine. All gasoline today contains additives that will take care of your car just fine.

Originally Posted by Soliditude

From multiple BMW drivers who used less-than-premium fuel for a while. Messes something up, gives sensors the wrong reading, and overtime, your cats go. I'm not a mechanic, so I don't know how it works, but I personally know people who did that and then said, "damn, I wish I stuck to premium." It might not be the same with our G's, but still. Factually, using less-than-premium in a car that requires premium does no good.

Originally Posted by Tek-C

I agree, if you are worried about gas prices, then you shouldn't have bought a car with bad gas mileage. I didn't buy my G thinking about the MPG. Well, when I read about it before I bought, I said damn! but, I really wanted it, so it wasn't a factor in my decision.

Originally Posted by irrelevant

Personally, after seven years driving a 150-hp 1973 Dodge Charger that would consistently get 14 m.p.g. on the highway, I don't understand why people think the G gets "bad" gas mileage. For a powerful, normally-aspirated, fun to drive car, the G gets very good gas mileage. It's no Civic..and I wouldn't enjoy driving a Civic.

Originally Posted by irrelevant

Personally, after seven years driving a 150-hp 1973 Dodge Charger that would consistently get 14 m.p.g. on the highway, I don't understand why people think the G gets "bad" gas mileage. For a powerful, normally-aspirated, fun to drive car, the G gets very good gas mileage. It's no Civic..and I wouldn't enjoy driving a Civic.

Originally Posted by dopetime

LOL ignorance at its finest.

Originally Posted by adroitcaptor

There is a lot of wrong, unsupported, and plain fabricated information in this thread. (There is also some accurate information…) Please do not rage on me until you try and understand what I am saying in this post from an objective standpoint. I am NOT flaming anyone NOR is any part of this post aimed at anyone specific!

Because different stations use different services with different additives at different times, it is near impossible to delineate REAL differences of brand gasoline(s). That said there are some stations that are much more consistent than others.

Before you go buying additives look at the cost of racing fuel/aero grade fuel and do some math. If you need help or further explanation I would be happy to give it. Suffice it to say, MOST additives, unless used solely as a detergent, are a rip off.

There is no more "power" in one fuel from another, so to say. I will steer clear from giving a lecture on iso-octane and the comparative RON (rating system). HOWEVER the caveat is in the semantics. The ‘raw’ fuel itself has no more ‘power’. In fact, this myth of one fuel burning ‘faster’ or more ‘powerful’ is an absurdity. The difference that you are seeing is the fuel’s resistance to engine-knock (pre/self-ignition). In a very basic explanation, the higher the octane the higher pressure the fuel can be compressed to before it ‘self-ignites’. Anyone who understands turbo systems must have a strong grasp on this concept (or follow it unknowingly). There is one major deviation from this “fuel is fuel” explanation. That is the additives a company/refinery will/might put in the fuel. THIS INCLUDES, but is obviously not limited to, ethanol. When we consider these bastard excuses for profit and EPA mindless communism, we start seeing a difference in ‘energy’ output / (specified) volume of fuel. Methanol has less than half of gasoline’s specific energy / energy by raw volume; ethanol is generally about one third. SO the 91octane of America (with 10% ethanol) has less energy by volume then Europe’s 91octane (with 3%). Where these numbers are not PftA , they are not exact, that would require a lecture style post... lol

I would argue, and could support, that additives DO matter. (To what degree is quite another issue.) What is more concerning to me is how the gas is kept, transported, and refined. If you want to argue that a person can go to 5 different stations and all the 5 petrol samples will be the same, I will point out you do not have a grasp on the reality of this subject.

Many made the point that the same truck will go to the two different places. Where they might receive the same gasoline this assumption cannot always be concluded. The obvious point being - a single truck can provide more than 1 RON type of fuel.

Subjective evidence is just that. People, let us not go around making rash judgments, statements, or even postulations based on a one time, uncontrolled experience. Right as we may be, it is absurd to pose knowledge based on this type of lazy behavior. I always maintained [on other car forums] that if you do not KNOW give an opinion stated as an opinion; if you KNOW help others to understand from fact.

Bottom line, there are many factors that contribute to knock. Do not think that running a higher octane will get you ‘more power’. Once the limitations of timing (not considering mods or dyno tuning) have been reached, there is ‘nothing’ more to gain by higher grade fuel. The antithesis of this is also true – once your vehicle’s timing has compensated to its limit, a lower grade fuel will reduce performance.

I hope this helps people to understand some of the ‘science’ of this issue. If you would like clarification, think I am full of it, or simply want more information, let me know; I would be happy to help/respond.

Originally Posted by CateyeRR

When no person in this thread can offer a single shred of evidence that any brand is better than any other brand? All that's been displayed is hearsay and opinion. I feel like I'm one of the few that has some common sense.

Originally Posted by CateyeRR

When no person in this thread can offer a single shred of evidence that any brand is better than any other brand? All that's been displayed is hearsay and opinion. I feel like I'm one of the few that has some common sense.

Originally Posted by SgtGoldy

I second that