Gasoline: Premium vs. Non-Premium

[renold458]

I searched the forums and found this discussion regarding the S4/RS4. I've been adding in 93 to my car since I bought it, as premium gas is what I've been told to put in to keep the health of my car. I've been hearing from various sources that there is no difference in terms of "health" for an engine between the different gas types, while other sources says otherwise. Hell, my cousin told me to put 93 in my '99 Nissan Altima, which has been running 87 for the past 3 years I've owned. In terms of the B6 A4, the 1.8T Quattro model specifically, does gas make the difference? Are there performance changes, gas mileage changes, and are there potential/definite dangers to using a different octane level? I, for one, will probably still put in premium in my car, as it's what has been recommended to me and gas isn't so expensive where I live. This thread is more for factual information purposes regarding my A4 model but also all of the B6 models, as I'm curious to know and I bet others are as well.

[old guy]

From the manual:

[renold458]

From the manual:

There we have it folks. That's interesting then, so what am I really gaining from putting in 93?

[Seerlah]

Standard to know. If stock, you can run 91. No reason to place in 93 unless you feel it will give you more hp...which it won't. After that, you run whatever fuel you are tuned for. Factory tune calls for 91 minimum. All this is due to ignition timing pull if you were to run a fuel the car's ECU is not written for. With that being said, many people place 87/89 in their tanks when doing long distance trips. But (big but), they make sure to stay out of boost when doing so. It's all highway miles.

[renold458]

Standard to know. If stock, you can run 91. No reason to place in 93 unless you feel it will give you more hp...which it won't. After that, you run whatever fuel you are tuned for. Factory tune calls for 91 minimum. All this is due to ignition timing pull if you were to run a fuel the car's ECU is not written for. With that being said, many people place 87/89 in their tanks when doing long distance trips. But (big but), they make sure to stay out of boost when doing so. It's all highway miles.

As OG showed though manual says 87 is fine, so why the discrepancy, unless the manual mentions avoiding boost? My area only has 87/89/93 octane gas. I'm fully stock, I just want whatever wont kill my engine while being good on mileage.

[old guy]

There we have it folks. That's interesting then, so what am I really gaining from putting in 93?

Better performance and better gas mileage.

[Seerlah]

I don't own a B6, and this is news to me. My gas lid states 91 minimum. Ha. Ran 91 since I bought it, till I picked up a 93 tune. Been on some type of 93 tune since. If you want what is best for your engine, 93 will be your best bet as far as not pulling ignition timing goes. Since you don't have 91 in your area, I would run 93.

[old guy]

Check the lid closely. It probably states 91 RON which is pretty much the same thing as 87 AKI.

[renold458]

^Pretty much. RON is used in other countries while USA uses AKI. Either way I doubt you're hurting anything when you used 91. Now I wonder, whats the MPG gain from 87 to 93?

[old guy]

Easy enough to try it and see. I had to use 87 once because it was all that was available. I didn't check my mileage but I most certainly felt the difference in performance.

[renold458]

I'll give it a shot in better conditions, I just have too many factors that's already killing my gas mileage like bad tires and a vacuum leak that I have yet to find the time to bring it in to a shop to check out.

[y0itzflip]

oh wow. I've been using 93 for no reason on my 3.0 while hating on my girls civic.

(still hating on it since it's so reliable while mine just looks pretty in the driveway forever broken.)

[diagnosticator]

oh wow. I've been using 93 for no reason on my 3.0 while hating on my girls civic.

(still hating on it since it's so reliable while mine just looks pretty in the driveway forever broken.)

It will stay broken in the driveway unless you fix it or take it to a shop for repairs. It won't fix itself.

[SJorge3442]

oh wow. I've been using 93 for no reason on my 3.0 while hating on my girls civic.

(still hating on it since it's so reliable while mine just looks pretty in the driveway forever broken.)

I ran 87 once in my 3.0 when it wasnt my 3.0 yet (bought it off a close friend) and you could tell that seriously timing was getting pulled. The 3.0 is a bum of an engine to begin with, no need to pinch pennies at the pump and run 87.

[ECS Tuning-Audi]

Currently I've been running 87 because it's so stinkin' cheap right now while 93 is still over 2 bucks a gallon or more. Haven't seen any adverse effects. I will say I only run lower octane fuel in the cooler months. In the summer intake temps can get pretty high when the tiny intercooler heat soaks so the 91/93 is good protection against pre-ignition, which can damage your engine.

Jason

[renold458]

I ran 87 once in my 3.0 when it wasnt my 3.0 yet (bought it off a close friend) and you could tell that seriously timing was getting pulled. The 3.0 is a bum of an engine to begin with, no need to pinch pennies at the pump and run 87.

Some areas the jump between 87 and 93 is a decent difference, so sometimes penny "pinching" has to be done. In my area 87 can be 70 cents to a dollar cheaper than 93, where the cheapest I've seen 87 was 1.96 and 93 at it's cheapest was 2.65 and that adds up given these cars see the pump more often than other cars, especially if its daily driven.

[renold458]

Currently I've been running 87 because it's so stinkin' cheap right now while 93 is still over 2 bucks a gallon or more. Haven't seen any adverse effects. I will say I only run lower octane fuel in the cooler months. In the summer intake temps can get pretty high when the tiny intercooler heat soaks so the 91/93 is good protection against pre-ignition, which can damage your engine.

Jason

Do you recommend this with a modified setup or does this also carry true with a stock setup?

[SJorge3442]

Some areas the jump between 87 and 93 is a decent difference, so sometimes penny "pinching" has to be done. In my area 87 can be 70 cents to a dollar cheaper than 93, where the cheapest I've seen 87 was 1.96 and 93 at it's cheapest was 2.65 and that adds up given these cars see the pump more often than other cars, especially if its daily driven.

I'm not gonna sit here and preach the whole "Pay to Play" rule, but this is a perfect example of that mantra. These cars cost more to keep on the road, thats just how it works. Whether that be parts or fuel, its just the whole VAG game. You're new on here, so you'll quickly learn that.

Even at $.70 more a gallon (pretty extreme diference if you ask me. In the greater NYC/Philly area 91/93 is usually $.40 more/gal) using 15K miles a year and 22mpg, you're looking at a cost of fuel difference of $470. If you need to be pinching pennies, you bought the wrong car. I usually don't waste my time doing this sort of thing, but at the end of the day, total cost of fuel really doesn't change much in the whole scheme of things. /rant

[jesse500]

Octane levels only dictate when the fuel/air mixture burns based on ignition source/heat. Under high load/heat/lots of timing, you can run into problems of pre-ignition with lower octane levels (matters alot on what temps you drive at, what mods you have, and how you drive). 90% of people, could run 87/89 octane on a stock car and be 100% fine. If you drive your car is very warm areas, then it will matter a little more.

N/A cars are less prone due to detonation due to low octane levels, boosted vehicles are worse, Due to the added fuel/air in combustion chamber. (generalized).

When a car is designed to run on a certain octane level, its engine flow characteristics and timing is set based on a fuel (mostly just ECU tuning). So you will see your optimal fuel mileage on that fuel grade. and you are getting more complete burn/getting all out of each ignition sequence as 91-94 resists igniting longer than 87-89. SO your striving to get every bit of the HP out of the motor.

Things to keep in mind:

--87-89 contain the Ethanol additive. which is hard on fuel pumps, diaphragms, fuel lines & filters.
--91-94 octane usually don't contain Ethanol, but you will never get 100% ethanol free fuel. due to fuel pumps. unless the person before you got premium too.
--fuel companies & fuel station matter too. Some places keep separate 87/91/93, etc... tanks, and the feeds come from them. Others keep 2 tanks, 87 & a 95-98 octane. And they mix the fuel as its pumped to the hose into your car.
--Water. Water is a big one. Water seems to always find its way into tanks/fuel. Water diminishes octane levels. So say your pumping 87, and you happen to be at a bad station, or a good station had a bad batch of fuel, or one of thier tanks under ground have a seep hole. Now your pumping 85-86 octane, not 87. If you were pumping 91-94, you now lucked out, and got 87-89 octane in your car. so your still safe. Will your car still run on 85 octane? Probably, but not very well, and potentially harmful.

Its a little different for me, to others. I live in Northern Ontario. Its below zero at least 1/3 of the year. We get good winter fuels here, and IAT's are low in the winter months (November-April).

Moral of the story. higher octane is a better Idea to run, especially on a vehicle designed to run 91-94. Will it hurt it to run 87-89? 99% of the time no. Will you see/feel a little performance upgrade from 87 octane to 94 octane? Most Likely.

Me, for one, I usually run 87 in winter months, with a tank of premium every 3rd or so tank. just too keep octane up a little incase of a little water or something. In the summer, I run 91/93/94 octane. I only fill up at Shell/Esso/Petro Canada if I can help it.

[renold458]

I'm not gonna sit here and preach the whole "Pay to Play" rule, but this is a perfect example of that mantra. These cars cost more to keep on the road, thats just how it works. Whether that be parts or fuel, its just the whole VAG game. You're new on here, so you'll quickly learn that.

Even at $.70 more a gallon (pretty extreme diference if you ask me. In the greater NYC/Philly area 91/93 is usually $.40 more/gal) using 15K miles a year and 22mpg, you're looking at a cost of fuel difference of $470. If you need to be pinching pennies, you bought the wrong car. I usually don't waste my time doing this sort of thing, but at the end of the day, total cost of fuel really doesn't change much in the whole scheme of things. /rant

Its not a question of if I need to pinch pennies or not (and some things happen in life where you would HAVE to at some point, life happens), just because you own a more expensive car does not in any shape or form mean you have to put in the extra cash, "if" you don't have to. Just because you can afford everything the vehicle throws at you/requires doesn't mean you won't want to save money where you can, and for me almost $500 a year adds up, that can go to other maintenance on the vehicle where you really don't want to skimp on. A good example was when my alternator crapped on me a few days ago, it was a choice of going to a German-only mechanic and have a new one placed in for $800, or get the same job done at my mechanic for $300. Could I afford both? Of course, but why spend the extra money when they cheaper job gets the job done well enough? And that's just how my area in RI/MA is, its that significant of a difference. As I said before, I probably still won't put in 87 (but I'll give it a try for science), I just wanted this thread here for informational purposes. Our manual says 87 is fine, Audi then, by logic, must've engineered the vehicle to run fine with 87, albeit it being the minimum. But nice write up, it'll help people who come in here see a difference.

[renold458]

Octane levels only dictate when the fuel/air mixture burns based on ignition source/heat. Under high load/heat/lots of timing, you can run into problems of pre-ignition with lower octane levels (matters alot on what temps you drive at, what mods you have, and how you drive). 90% of people, could run 87/89 octane on a stock car and be 100% fine. If you drive your car is very warm areas, then it will matter a little more.

N/A cars are less prone due to detonation due to low octane levels, boosted vehicles are worse, Due to the added fuel/air in combustion chamber. (generalized).

When a car is designed to run on a certain octane level, its engine flow characteristics and timing is set based on a fuel (mostly just ECU tuning). So you will see your optimal fuel mileage on that fuel grade. and you are getting more complete burn/getting all out of each ignition sequence as 91-94 resists igniting longer than 87-89. SO your striving to get every bit of the HP out of the motor.

Things to keep in mind:

--87-89 contain the Ethanol additive. which is hard on fuel pumps, diaphragms, fuel lines & filters.
--91-94 octane usually don't contain Ethanol, but you will never get 100% ethanol free fuel. due to fuel pumps. unless the person before you got premium too.
--fuel companies & fuel station matter too. Some places keep separate 87/91/93, etc... tanks, and the feeds come from them. Others keep 2 tanks, 87 & a 95-98 octane. And they mix the fuel as its pumped to the hose into your car.
--Water. Water is a big one. Water seems to always find its way into tanks/fuel. Water diminishes octane levels. So say your pumping 87, and you happen to be at a bad station, or a good station had a bad batch of fuel, or one of thier tanks under ground have a seep hole. Now your pumping 85-86 octane, not 87. If you were pumping 91-94, you now lucked out, and got 87-89 octane in your car. so your still safe. Will your car still run on 85 octane? Probably, but not very well, and potentially harmful.

Its a little different for me, to others. I live in Northern Ontario. Its below zero at least 1/3 of the year. We get good winter fuels here, and IAT's are low in the winter months (November-April).

Moral of the story. higher octane is a better Idea to run, especially on a vehicle designed to run 91-94. Will it hurt it to run 87-89? 99% of the time no. Will you see/feel a little performance upgrade from 87 octane to 94 octane? Most Likely.

Me, for one, I usually run 87 in winter months, with a tank of premium every 3rd or so tank. just too keep octane up a little incase of a little water or something. In the summer, I run 91/93/94 octane. I only fill up at Shell/Esso/Petro Canada if I can help it.

I guess here in RI even the "crap" gas stations have had pretty good gas over the years, oddly enough I've heard Shell in some areas being the worst. Obviously people have no real scientific basis as to why, but hey just found it interesting. You're the second person who mentioned putting in a lower grade during colder weather, I never heard of that until now. Given that it gets cold here on the east coast during the winter time I might have to reconsider putting in 93 all season (if I even drive the car as I'm considering keeping it garaged for the meantime, but rumors are going around we won't get much snow). I run stock, so as long as my car isn't feeling like "complete" shit from 87 then I guess it couldn't hurt.

[jesse500]

Its not a question of if I need to pinch pennies or not (and some things happen in life where you would HAVE to at some point, life happens), just because you own a more expensive car does not in any shape or form mean you have to put in the extra cash, "if" you don't have to. Just because you can afford everything the vehicle throws at you/requires doesn't mean you won't want to save money where you can, and for me almost $500 a year adds up, that can go to other maintenance on the vehicle where you really don't want to skimp on. A good example was when my alternator crapped on me a few days ago, it was a choice of going to a German-only mechanic and have a new one placed in for $800, or get the same job done at my mechanic for $300. Could I afford both? Of course, but why spend the extra money when they cheaper job gets the job done well enough? And that's just how my area in RI/MA is, its that significant of a difference. As I said before, I probably still won't put in 87 (but I'll give it a try for science), I just wanted this thread here for informational purposes. Our manual says 87 is fine, Audi then, by logic, must've engineered the vehicle to run fine with 87, albeit it being the minimum. But nice write up, it'll help people who come in here see a difference.

Regarding my post above. I missed the part about S4/RS4. So your car is N/A. the difference to 87 to 91-94 is minor. unless you live in a place of very warm climate, or your beating your car daily. if you use it primarily for regular road/highway use. 87-89 is all you need.

[ECS Tuning-Audi]

Do you recommend this with a modified setup or does this also carry true with a stock setup?

Due to the higher boost levels from a modified vehicle I would stick with premium fuel. Factory programming is very low boost.

Not to mention I drive close to 45K miles a year so anytime I can save a little on fuel I will - even though I'm averaging 28-29 MPG.

Jason

[Charles.waite]

The compression ratio of the motor makes a huge difference to what type of gas you should use too.

Additionally, its VEYR hard in many places to get gas without ethanol. 99% of stations in Washington use up to 10% ethanol in their gas, and 92oct is the max nearly everywhere around here.

I always buy 92. I don't see the point in running 89 just to $0.10 a gallon, $1.50 tank, or ~$40/year given the little mileage I drive.

A long time ago My dad and I were driving to Ohio from Seattle, and wanted to experiment with gas mileage and octanes. We filled up twice with 87 and averaged the mileage and then the rest of the trip was 91/92/93 (depending on the state) and we saw a 10% swing in mileage in favor of the higher octane mix. This was on a 9-5 2.3t 4-speed auto and we averaged in the 27mpg range cruising between 70 and 85.

By my math (granted this was a long time ago and my memory is a bit fuzzy) it was cheaper to buy premium I recall.

[renold458]

Due to the higher boost levels from a modified vehicle I would stick with premium fuel. Factory programming is very low boost.

Not to mention I drive close to 45K miles a year so anytime I can save a little on fuel I will - even though I'm averaging 28-29 MPG.

Jason

Interesting. When February rolls in I plan on modifying my car just a tad bit, so this will be useful to know. And that's a lot of mileage for this car, how do you get numbers like that if you don't mind me asking?

The compression ratio of the motor makes a huge difference to what type of gas you should use too.

Additionally, its VEYR hard in many places to get gas without ethanol. 99% of stations in Washington use up to 10% ethanol in their gas, and 92oct is the max nearly everywhere around here.

I always buy 92. I don't see the point in running 89 just to $0.10 a gallon, $1.50 tank, or ~$40/year given the little mileage I drive.

A long time ago My dad and I were driving to Ohio from Seattle, and wanted to experiment with gas mileage and octanes. We filled up twice with 87 and averaged the mileage and then the rest of the trip was 91/92/93 (depending on the state) and we saw a 10% swing in mileage in favor of the higher octane mix. This was on a 9-5 2.3t 4-speed auto and we averaged in the 27mpg range cruising between 70 and 85.

By my math (granted this was a long time ago and my memory is a bit fuzzy) it was cheaper to buy premium I recall.

Wow I wish that was the price gap here. I really want to test this out for myself and give you guys my numbers, so far this thread has been (in my opinion) more informative and "settled" than the S4/RS4 one. Thanks so much!

P.S. I just realized I could multi-quote, I've done it on other forums and don't know why I never did here.

[Charles.waite]

Well Seattle's gas prices are astronomical usually, so we generally pay over $1 more than the national average. Currently its at $3.09 (for 92 at my nearest station) which is as cheap as I can remember in the past year but still way above most everywhere in the country. And I actually just checked and its $.20 between 89 and 92. So that does change the math significantly but its still not enough to make me care about bumping down to 89. $80 over the course of the year is a wash for me. If I drove more than 6-7k miles in a year I would probably care more though.

And when you're modified think about your engine. You're running much more boost pressure and much higher temps. Higher octane gas is very important to maintain the performance and not screw up proper ignition.

[john_gonzo]

... A long time ago My dad and I were driving to Ohio from Seattle, and wanted to experiment with gas mileage and octanes. We filled up twice with 87 and averaged the mileage and then the rest of the trip was 91/92/93 (depending on the state) and we saw a 10% swing in mileage in favor of the higher octane mix. This was on a 9-5 2.3t 4-speed auto and we averaged in the 27mpg range cruising between 70 and 85.

By my math (granted this was a long time ago and my memory is a bit fuzzy) it was cheaper to buy premium I recall.

The first two tanks got you to the Great Divide then after that it was all downhill to the Mississippi River.

[cschuster]

I did the math a few years ago with 2-3 tanks apiece on the highway, and found that the cost difference was offset completely by the mpg increase going from 87 to 91-93. This was when gas prices were way higher too.

Sure, the fill up is cheaper with 87, but you will get 30-40 miles less per tank. Just put in premium to begin with and call it a day.

[jesse500]

Where I am from (northern Ontario) Gas prices are silly lol. I filled up today actually.

87 - $1.049 per Litre - $3.97 per US Gallon
89 - $1.129 per Litre - $4.27 per US Gallon
91 - $1.169 per Litre - $4.42 per US Gallon

I had 1/4 tank of 91 in the car, so I filled it up with 87.

[CyberPMG]

I did the math a few years ago with 2-3 tanks apiece on the highway, and found that the cost difference was offset completely by the mpg increase going from 87 to 91-93. This was when gas prices were way higher too.

Sure, the fill up is cheaper with 87, but you will get 30-40 miles less per tank. Just put in premium to begin with and call it a day.

That's the big thing people forget when doing comparisons between octane ratings and overall fuel cost. The fuel consumption does not remain constant. It also changes with the octane rating (driving conditions and driving habits aside).

[old guy]

Agreed ↑ This thread has a whole lot of verbage for such a simple answer: Clicky click®

[WB650]

Highest we have in Cali standard is 91, so thats all I run. In my Cadillac it called for Premium but I always ran 87 b/c there was no difference

[y0itzflip]

It will stay broken in the driveway unless you fix it or take it to a shop for repairs. It won't fix itself.

you are correct. it's a slow process as I'm fixing a bunch of things at once.

I ran 87 once in my 3.0 when it wasnt my 3.0 yet (bought it off a close friend) and you could tell that seriously timing was getting pulled. The 3.0 is a bum of an engine to begin with, no need to pinch pennies at the pump and run 87.

lol I doubt I was going to go to 87 anyway. I've been running 93 in my cars for years. (Hondas with built motors, e90 and now this b6) the price difference is a lot per gallons, but I'm used to it.

Some areas the jump between 87 and 93 is a decent difference, so sometimes penny "pinching" has to be done. In my area 87 can be 70 cents to a dollar cheaper than 93, where the cheapest I've seen 87 was 1.96 and 93 at it's cheapest was 2.65 and that adds up given these cars see the pump more often than other cars, especially if its daily driven.

it does add up. luckily my b6 isn't my daily right now. and I've also moved within 5 miles of my job. we will see how the car likes the trips when I start to daily it again.

[redline380]

Check the lid closely. It probably states 91 RON which is pretty much the same thing as 87 AKI.

Nope, lid says 91 AKI, 95 RON on a B5, and I can't imagine B6 is any different. The thing is you can use 87, but 91 is what you should run for the overall health of your engine.

What Old Guy's photo doesn't show is Audi's recommendation to run 91, says so right in the manual. It does say 87 is acceptable, but 91 is preferred.

[old guy]

I just ran out in the rain and checked my gar door flap. It states the same thing as yours.
95 RON
91 R=M/2 (AKI)

As stated previously, I don't advocate using anything other than "Hi-Test". But using 87 AKI shouldn't cause any damage.

[tHatOne guY]

Regarding the ethanol content in our gasoline now... check out this site- http://pure-gas.org/

Have been using 89 for 2 years now in my B5 and my B6, no issues. Less power maybe but nothing really noticeable. As far as MPG I'll have to check and report back. Even ran some logs in the past with 89 in the tank and no knock was found.

Fuel prices being where they are now, am leaning towards 91.

[redline380]

Regarding the ethanol content in our gasoline now... check out this site- http://pure-gas.org/

I don't know about other states, but MN mandates all on road vehicles use e10. Pure gas is available, but scarce, and says right on the pump only for use in small engines. Ive tried pur 91 in my car before and they was not noticeable effect, so it cannot justify the price hike

[WB650]

Gas is way down right now, even where I live in the Bay Area. When high I'm usually paying $50+ to fill up. Just a couple days ago I paid $35 to top off from E

[Boost92]

wow, Gas is cheap in the US 😂

[cschuster]

1.65 for regular, 2.02 for premium here in Ohio. I never thought we would see gas prices under $3 ever again.