What type of Gas? (Full Version)

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What type of Gas?

  

dblock110 -> What type of Gas? (8/4/2006 9:11:37 PM)

I was wondering what type of gas everyone puts in their A6. i have a 1998, and in the manual im pretty sure it says use premium. i use premium all the time but my friend will put premium one time, regular the next, then premium again, and so on in his car.

what do you guys do.

what do you guys recommend.

  
SouthboroAudiGuy -> RE: What type of Gas? (8/4/2006 10:23:23 PM)

You may want to do a search on this. Been discussed many times and is a subject of much controversy. Bottom line: 87 will not hurt your car. 91+ will give you more power and a bit better gas mileage (not enough to cover the extra cost, but a bit more). Brands only vary in terms of the additives they add. As such, unless you have a particular taste for one detergent over another, brand does NOT matter.

dankhound -> RE: What type of Gas? (8/11/2006 8:26:00 PM)

Actually using to low of an octane can cause knocking and pinging. Mostly in the turbo engines at higher altitudes.

gpz -> RE: What type of Gas? (8/22/2006 9:13:24 PM)


quote:

ORIGINAL: dankhound

Actually using to low of an octane can cause knocking and pinging. Mostly in the turbo engines at higher altitudes.


His car is a 98 2.8, just like mine. No turbo, and it has a knock sensor that retards the ignition timing to prevent knocks.

SouthboroAudiGuy -> RE: What type of Gas? (8/22/2006 9:23:02 PM)

quote:

ORIGINAL: dankhound

Actually using to low of an octane can cause knocking and pinging. Mostly in the turbo engines at higher altitudes.


Um... no. Absolutely not. As noted by another poster, the car has sensors that will change the timing to prevent this. I was told just last night by an Audi technical engineer and an Audi service trainer that 91 is recommended (for best performance) but 87 will do absolutely NOTHING to hurt your car.

gpz -> RE: What type of Gas? (8/22/2006 9:43:39 PM)


quote:

ORIGINAL: SouthboroAudiGuy

You may want to do a search on this. Been discussed many times and is a subject of much controversy. Bottom line: 87 will not hurt your car. 91+ will give you more power and a bit better gas mileage (not enough to cover the extra cost, but a bit more). Brands only vary in terms of the additives they add. As such, unless you have a particular taste for one detergent over another, brand does NOT matter.


Not true, and true...

Not True: Economy using premium fuel: According to my calculation, it costs me about $1.80 more to fill up with premium fuel compared to mid-grade, and $3.60 more compared to regular. (18 gallons x $3.29 per gallon premium... gasoline, for the first time in my lifetime, costs more now in Washington State than it does in Oregon). I have also carefully calculated that I average 23 - 24 mpg on my commute to work. (Mostly highway... stop and goes KILLS the economy, like as low as 17 mpg around town). When I've used mid-grade and regular, my economy averaged 21 - 22 mpg on the exact same commute under exactly the same weather conditions (hot and dry.) and exactly the same speed (61 mph highway, 41 mph in town, set on the cruise control and confirmed on my GPS). So, 24 mpg times 18 gallons = 432 miles per tankful. At the lower economy, 22 mpg X 18 gallons = 396 miles per tank. This is a delta of 36 miles. 36 miles / 22 mpg = 1.64 gallons X $3.09 per gallon regular = $5.06. This means that it would costs $1.45 more to go the same total distance using the regular gasoline! Might as well buy the premium, though often I just fill up with mid-grade.

Absolutely true: All gas is the same except for the detergent additives. All the oil companies use the same transport pipelines. Oil company A puts in X number of units of premium and regular grade gasoline on one end, and take out X number of units on the other end, as do all the other oil companies. These X number of units may very well have been produced by Company B, C, or D, and is probably well mixed at the terminal end anyway. When they take out X number of units and pump it into a fuel truck the fuel additives are in the tanker truck, not in the pipeline. The quality of the gasoline is closely monitored to ensure it meets standards going into the pipeline. Mid-grade is created by mixing the premium and regular. Also, the additives in the premium fuel are exactly the same as those in the regular fuel, as mandated by law actually.

Now that being said, some gas stations are better than others. Some stations have problems with water intrusion in their underground tanks, or else has water magically gets into their stored fuel. (I have tested gas for water many times and found it... glass jar of fuel in a dark cabinet, check for seperation)Some stations have poorly calibrated pumps, and isn't it funny that they are always in error towards measuring more gas pumped than actual, never less. (I also have reported a notoriously bad station in my town, and the state busted them twice for re-calibrating their pumps after being inspected by the state.)Personally, I always buy my fuel from the busiest stations, as there is less chance for fuel contamination that way since their turnover is higher.

cary12 -> RE: What type of Gas? (8/22/2006 9:55:46 PM)

I don't care what anyone says or what the statistics are. I have a 2001 A6 4.2 and I only use the highest grade premium I can find. It's only a couple bucks more to fill up and you have the slight sense of security with the premium fuel. Not a mechanics advise or anything but if you love your car and want to do everything you can to make it run as well as it should, shouldn't you put good gas in her? [;)]

SouthboroAudiGuy -> RE: What type of Gas? (8/22/2006 10:13:25 PM)

No doubt about it. These are our babies and we all love to pamper them. I generally tend to put premium in mine but have been switching a bit to mid or regular lately because many gas stations are jacking up the delta between the grades.

That said, I do think it is important to get the FACTS on the table because all too often, I see people spout BS that anything less than 91 will hurt your car. Just isn't true.

dankhound -> RE: What type of Gas? (8/22/2006 11:02:05 PM)

An audi engineer told you huh. Probably the same guy that put the cupholder above 1000 dollars worth of electronics(radio and ac control head). Put 85 in a 2.7 at altitude and take it down to sea level and you get all sorts of audible pinging. The computer can only do so much to prevent pinging. There is a max retard setting. Also pinging doesnt have to be audible to do engine damage. By the time it audible youre already doing damge.

SouthboroAudiGuy -> RE: What type of Gas? (8/22/2006 11:07:47 PM)

Get snide about it if you want, but I have heard this and read this in many, MANY places. Put in your car what you like, but I don't see the point of trashing somebody you don't even know/haven't met because he sees the issue differently from you. This was a field engineer who has spent a lot of time modding Audis in a previous job -- not some corporate puke type who has not been out there. Very cool guy who seemed very credible.

Sorry my friend, my money is on him.

BTW, where are YOU seeing 85? Least we have around here is 87.

gpz -> RE: What type of Gas? (8/23/2006 12:56:11 AM)

In some places in the U.S., high elevation areas, like eastern Idaho, Utah and Wyoming, the stations routinely sell 85 octane due to the higher elevation and lower density air. They also often sell ethanol at the pump as regular fuel. They do this because they can get away with it.

So yeah, run on some 85 octane, which is below the minimum RON + MON / 2 standard for most all cars these days, go down to sea level and yes, it will ping.

SouthboroAudiGuy -> RE: What type of Gas? (8/23/2006 8:26:27 AM)

Well, I think we can assume that my sources were NOT including this extreme example. Interesting to learn, however.

Joeski -> RE: What type of Gas? (8/23/2006 8:55:55 AM)

I agee with Southboro. I think it can come down to personal preference and the location you reside in! I live in Maryland and I have used 87 Octance in my 00 2.7T and I find the performance was not as good as if I ran a 93 Octane. I have not experienced any pinging. We have a couple places that sell 100 Octane (price is through the roof).

In the summer, I need to run high test simply because of the outside weather. We get very hot and humid. I noticed if I run 87 Octane in the heat of summer, my car is a little more sluggish then if I was to run 93 Octane in the summer. One thing I can tell you is my car loves the fall season, when temperatures drop a little and the air is a little cooler and denser.

In the end for me, I run at least 93 Octane. It gives me piece of mind and I think my car is happier because of it!

OOOO



[image]local://upfiles/13659/4E53C9C6C81C40E28DF25101FA5724E7.jpg[/image]

Boston Driver -> RE: What type of Gas? (8/23/2006 9:09:43 AM)

I see no reason why anyone would try to asve a few pennies per gallon and put lower grade gas in the tank. You'd save much more money buying generic brand cola instaed of drinking Coke and Pepsi, but very few folks skimp on the things that they like. Our cars like 91+ octane gas, so that is what I give to her (93 here in MA).

SouthboroAudiGuy -> RE: What type of Gas? (8/23/2006 9:50:25 AM)

quote:

ORIGINAL: Boston Driver

I see no reason why anyone would try to asve a few pennies per gallon and put lower grade gas in the tank. You'd save much more money buying generic brand cola instaed of drinking Coke and Pepsi, but very few folks skimp on the things that they like. Our cars like 91+ octane gas, so that is what I give to her (93 here in MA).


I've got a fridge full of RC cola. You want to make something of it? :-P

muphasta -> RE: What type of Gas? (8/23/2006 3:10:14 PM)

RC is the bomb! I rarely drink cola anymore since I am not suposed to have caffine, but I loved RC!

My dring of choice is Vernor's Ginger Ale. Man, that is so good!

My sentra said to use premium, so I did. I'll be using it my my 2.7t as well. I thought it was funny on the sentra forums I was on that the guys would put hundreds if not thousands of dollars in mods in there car to make it faster, but they'd skimp on the gas. It seems to me that you'd want the best performing fuel for a performance car. Especially when you've put a lot of money making an ok car much faster. (the sentra being an ok car)

SouthboroAudiGuy -> RE: What type of Gas? (8/23/2006 3:17:39 PM)

Ever tried Reed's Ginger Beer (non-alcoholic). Available at Whole Foods and Trader Joes. Very strong ginger flavor.

As I said above, I generally put premium in my ride because I want the additional fun factor when I hit the gas. Mid-grade or regular on occasion lately (unemployment will do that to ya). Just don't like to see the spread of modern-myths (no objection to the ancient and/or entertaining). The notion that a tankful of 87 octane is going to hurt your Audi is unfounded.

muphasta -> RE: What type of Gas? (8/24/2006 12:10:41 AM)

never tried it. my wife did bring me 3 different varieties of ginger beer/ginger ale, and they were too strong for me. Vernor's is perfect for me! Canada Dry sux in comparison!!

dankhound -> RE: What type of Gas? (8/25/2006 12:25:23 AM)

quote:

In some places in the U.S., high elevation areas, like eastern Idaho, Utah and Wyoming, the stations routinely sell 85 octane due to the higher elevation and lower density air. They also often sell ethanol at the pump as regular fuel. They do this because they can get away with it.

So yeah, run on some 85 octane, which is below the minimum RON + MON / 2 standard for most all cars these days, go down to sea level and yes, it will ping.

quote:

Well, I think we can assume that my sources were NOT including this extreme example. Interesting to learn, however.


Any good enginneer will look at all the examples. They wouldnt just exclude the extreme examples. In any case ,with rising gas prices ,the benifits of lower octane fuels lower price is not worth the decrease in fuel economy and performance. This following statement holds true for virtually all vehicles on the road in ALL conditions. Use the fuel grade that provides the greatest fuel economy. This will ensure the best value for your dollar (and performance) with no possible chance of engine damage.

gpz -> RE: What type of Gas? (8/25/2006 11:54:49 PM)


quote:

ORIGINAL: dankhound

quote:

Any good enginneer will look at all the examples. They wouldnt just exclude the extreme examples.


I consider myself to be a pretty good engineer (mechanical P.E.). This isn't a totally accurate statement. Examining and performing analysis on all examples and combinations of conditions may not be feasible or economically sound, especially when those examples are not statistically significant.

In the end sometimes you have to shrug your shoulders and assume that the end user is going to follow the manufacturer's recommendations and instructions... little things like maintenance schedules, using OEM spec replacement parts and oil, using minimum RON + MON / 2 fuel...... I personally wouldn't 'what if' the scenario of running 85 octane fuel... wouldn't be worth the money spent on the analysis...

SouthboroAudiGuy -> RE: What type of Gas? (8/26/2006 12:18:08 AM)

quote:

ORIGINAL: gpz
quote:

ORIGINAL: dankhound
quote:

Any good enginneer will look at all the examples. They wouldnt just exclude the extreme examples.

I consider myself to be a pretty good engineer (mechanical P.E.). This isn't a totally accurate statement. Examining and performing analysis on all examples and combinations of conditions may not be feasible or economically sound, especially when those examples are not statistically significant.


Glad somebody called him on this. Pretty much pegged my BS meter but this is turning into a piddling contest and that's when I sign off.

dankhound -> RE: What type of Gas? (8/26/2006 2:55:59 PM)

quote:

In the end sometimes you have to shrug your shoulders and assume that the end user is going to follow the manufacturer's recommendations and instructions... little things like maintenance schedules, using OEM spec replacement parts and oil, using minimum RON + MON / 2 fuel...... I personally wouldn't 'what if' the scenario of running 85 octane fuel... wouldn't be worth the money spent on the analysis...


This is the situation we are speaking of. Using a fuel of lower grade than the manufacturer specifications. Which in some extreame cases can cause engine damage. Using the recomended fuel will work 100 percent of the time. Using a lower grade fuel will work most of the time, but its not going to work in every situation. I was just trying to make people aware that using lower grade gasoline isnt ALWAYS the best situation.

jonny29 -> RE: What type of Gas? (8/28/2006 2:21:42 PM)

Just to chime in a note, when I had my acura, I did a lot of research on this and what it mainly came out to was the compression of the engine since that determines the rate of combustion. Higher compression is higher combustion so if your engine has a high compression, like v-tec engines, then youd need a higher octane so it can combust quicker. Feel free to change anything around if Im wrong...

ppgoal -> RE: What type of Gas? (9/8/2006 10:26:53 PM)

I guess the fact that I prefer to drink Guinness to Coors Light means I better start treating my 2003 A6 2.7T better and splurge on an occasional tank of premium. I did find mileage to be slightly better using premium over midrange, but many other factors affect mpg as well (tire pressure, air filter, pedal pressure, outside temperature, cruising speed, starts). I would never use regular.

I'm surprised at some of the attitudes among fellow Audi owners. I think we need to find a petroleum engineer (and fellow owner) who can comment on the differences in the products and the additives. I'm just happy to find the occasional station that sells midrange for the same price as regular.

BTW, I own a 05 Crossfire that also "requires" premium and use midrange. It runs great and returns 27-28 mpg highway (once had a high of 31). No ping and I've had it to 140 before chickening out. It's as fast as the stock A6 but it gives away a lot of weight in spite of having only 215 hp.

gpz -> RE: What type of Gas? (9/13/2006 4:06:33 PM)


quote:

ORIGINAL: ppgoal

I'm surprised at some of the attitudes among fellow Audi owners. I think we need to find a petroleum engineer (and fellow owner) who can comment on the differences in the products and the additives. I'm just happy to find the occasional station that sells midrange for the same price as regular.



I'm not a petroleum engineer, but a mechanical engineer who occasionally has to look at specifications and quality testing for the fuel oil used for running the emergency diesel generators at my plant. During my research I learned some interesting things about gasoline too, plus my 22 years of driving, riding, and turning wrenches on just about everthing under the sun.

Regarding differences in the products and additives, as I mentioned in a previous post, there are essentially none. All gasoline is essentially the same from company to company for regular and premium fuel, and has to be because the fuel is transported in pipelines. The quality of the gasoline going into the pipelines by the various oil companies is closely monitered and tested by an independent industry group in order to ensure that any single oil company is not cheating the others by putting a lower quality fuel into the pipeline. There is no way to ensure that a company gets its own product out of that pipeline at the terminal end you see. The standards used in the U.S. is the RON + MON / 2 octane testing method. Testing RON is controlled by ASTM standard D2699, and MON is ASTM standard D2700

As far as additives go, by law the additives that are put in regular and premium are the same. The additives themselves are propriatary and closely held trade secrets, however I really don't think it matters for the intent of this discussion, as the additive packages do not impact the octane numbers.

Mid-grade fuel is simply a (supposedly) 50 / 50 mixture of regular and premium fuels, mixed at the pump while you fill your car (though some stations do in fact have mid-grade tanks and the fuel was mixed elsewhere, most notably where they sell 85 octane as regular). I sometimes wonder if some stations don't cheat on this some. All it would take is to just throttle down the premium pump a bit from the volume that the regular pump runs, and it would be hard for a state agency to detect unless they took that sample to get octane tested. Typically though all the state inspection agencies check is that the pumped volume agrees with the indicated volume.

And again, as mentioned before, many western states in the Rockies sell 85 octane as regular unleaded due to the elevation effectively lowering the compression ratio of the motors. In fact this works for carburated motors, but for fuel injected motors not so much. Audi's minimum RON + MON / 2 number is 87 PERIOD.

The bottom line for me is this: Under controlled condtions, I have determined that for my car I get better gas milage using premium fuel, and this means that while I may pay more at the pump during a fill up, I do it less often and thus save money. Also, while my car has run fine on mid-grade, which I did often before I did my calculations and experimentation, you take your chances that you are getting ripped off when you pump it and it really isn't 89 octane, but something less. And, while I'm sure my car would run just fine with no damage on 87 octane, I simply won't do it because I have calculated that it is a waste of money.

My Isuzu Rodeo, on the other hand, does not get any better milage running premium fuel. Isuzu specified 87 octane, and that is what I run in it, with the following exception: When towing a trailer uphill, I have noticed some pinging on regular fuel, and that motor does not have knock sensors. So for trips when I'm towing a trailer, either my tent trailer or boat, I will pump either mid-grade or premium to prevent knock. (it also depends on what time of year it is and what the weather is like, and where I'm going...it knocks worse in the hot summer and going up long grades.)

  

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