Premium Gas or Unleaded for -04 330ci-

Claiming "my mpg is better now than then" is nearly impossible to nail down to a single factor such as fuel selection. Even getting your gas at a different station, or from a different pump at the same station can introduce variables.

Just because you set your cruise at "x" speed doesn't mean the drive was exactly the same. What's the elevation change between point a and b? Which was was the wind blowing? How much other traffic was on the road? What was the barometric pressure?

Given the right conditions, we could probably set up an experiment to show our cars getting better mileage than a hybrid.

Premium gas becomes more important at low altitudes, in cold weather, or with modded cars. On a bone stock e46 at say 5000 feet altitude regular gas is probably the same.

On a cold day at sea level that premium gas is of much more value.

Any car with turbo or supercharger must use the highest octane gas available. If you have a CAI you might only see its effect with high octane gas.

Essentially the more Oxygen is in your engine the more important Octane becomes.

Originally Posted by jasonbimmer

people never understood this. they always compare price at the pump rather than price down the road. but then again the majority of the population dont even know how to check engine oil.

The model doesn't apply everywhere. Lets say, like Canada, Europe, and the rest of the world excluding the states.

Premium is an extra $0.20 per liter ($0.75/gal more) in my area.

Originally Posted by ac_2007

The model doesn't apply everywhere. Lets say, like Canada, Europe, and the rest of the world excluding the states.

Premium is an extra $0.20 per liter ($0.75/gal more) in my area.

Exactly, hence why I have imposed a self-limiting price of $1.50/L. I just put in my first tank of regular after running premium for a while. Looks like a summer of regular ahead for me.

P.S. my engine still isn't blowned up.

Wow this is one of the most volatile (get it? wink wink) gas threads I've come across, even as far as gas threads go it's already nasty. . . But I gotta chime in, and to be honest I probably won't even peek at the follow-ups because I don't want to inspire another 8 pages of really poorly thought out "I DONT HEAR MY KNOCK SENSORS, YOU'RE SO STUPID!!!"

Anyway, it says near your gas cap and in your manual what octane gasoline you should use. And yes high elevations brings it down a bit. Besides retarding a little bit for lower octane (hook up a live OBD2 reader and you can probably get enough info off the standard generic OBD2 parameters to see how 87 vs 91 works in your engine). However, I think even more important than the resistance to detonation are the different detergent packages between different gasses. I have the Honda TSB that advises dealers to tell people to use Top Tier gas, I can post if you want. And I don't think Honda makes any cars that require premium, they're talking regular for Hondas.

Someone is pounding out on their keyboard right now "all gas is the same." You're right, the base stock is practically identical, sometimes manufacturers will even fill their base stock off each others refineries. However the detergent packages that get mixed in later are totally different between manufacturers and also between grades of the same manufacturer. Premium gas always gets the best detergent package.

If you're totally cheap, at least do like 5 consecutive fill ups of premium then 5,000 miles on 87, then repeat.

Also you may or may not know that BMW is in a group of manufacturers that has a standard set for their recommended gasoline that is beyond the spec of the current EPA standard. Their engines will run on anyone's gas, but these manufacturers are saying that they run best, and cleanest, etc., etc., with certain gas.

http://www.imakenews.com/bmwofmurray....cfm?x=b11,0,w

This isn't a deal like where Castrol pays BMW to be the recommended motor oil and get their name on the oil cap, this isn't a pay to play deal.

It sucks because most states have laws that require them to sample different manufacturers gas at different places every single month and do pretty elaborate testing on them, but they don't publish that information. You'd literally have to pay to get gasoline tested yourself if you wanted to test some of the mojo in it. Or, if you have a medium amount of a science background, do a lot of googling, and read the top tier gas manufacturers, and some research on bobistheoilguy.com in the gasoline forums where major science nerds hang out, you'll stick with Shell Premium. Just sharing what I have found through research, you do your own. Or just be a grumpy guy at a keyboard harassing people in all caps.

Also, you're seriously silly if you are making comments like "one tank my car felt like X, and the next tank I filled up with this other gas and it felt like Y and I got 2% better MPG." Do you have any ideas how many times something has to be done in automotive testing to throw out all extraneous influences and verify it as a repeatable circumstance with a delta greater than the margin of error? Hundreds of thousands if not millions of miles when all other factors are identical.

If you don't believe me, let's both change our head gasket at the same time (my e46 has around 50k miles on it) and take photos of the combustion chamber build up. I've used premium all 50k miles, so this would be directed towards someone that hasn't.

Originally Posted by 2003 325i

Exactly, hence why I have imposed a self-limiting price of $1.50/L. I just put in my first tank of regular after running premium for a while. Looks like a summer of regular ahead for me.

P.S. my engine still isn't blowned up.

You can't use a fancy word like "hence" and a made up word like "blowned" in the same post, you loose all cred.

Originally Posted by ChicagoRY

You can't use a fancy word like "hence" and a made up word like "blowned" in the same post, you loose all cred.

lose*



Oh and my contribution to the thread. GAS SUCKS FILL WITH WATER

http://www.drivecarwithwater.com/

TOTALLY NOT A SCAM

Legitimate question: Anyone ever run 100 unleaded in a M54?

Although my "testing" over the weekend showed less than 1% difference between "regular" and "premium" gas, others have pointed out that there are other differences and they are basically correct.
Speaking only for the US, different parts of the country get different blends of fuel at different parts of the year.
In Chicago, we get a "winter blend" that always gets blamed for an increase in fuel prices.
When the winter blend is gone, it also gets blamed for an increase in fuel prices in the Spring.

Also- you know those signs at the pump that say "may contain UP TO 10% Ethanol"? Ethanol is used as an octane booster, so guess which fuel has the most ethanol?
Premium. At least in my area. And ethanol has about 30% less energy released when burned than gasoline.
After 10 years of driving back and forth between Chicago and Atlanta, I've noticed a marked difference (10% increase) in milage once I start filling up in Southern Indiana and parts south. I do not know what is different about the fuel, but I get better milage and it is cheaper.

Comparing milage and fuels around the country(s) becomes rather difficult because of variables like this as well as your tires, the road surface, your speed, head winds....

Originally Posted by JohnIBarr01

Legitimate question: Anyone ever run 100 unleaded in a M54?

Yes I did, in Germany they have 101... It raised my milage from 405 to 440 for that one full tank.

101 is different in Germany than it would be in the USA.
Europe uses ROM only for octane rating, while USA uses ROM + MOT (R+M/2) to get the AKI octane rating seen at the pump.
What that means is that a fuel with a 101 ROM rating only might end up being 93 after the MOT (motor octane) rating gets figured in.
The MOT rating tends to be much lower.
There is no direct translation or comparison available to easily compare the ratings.

Originally Posted by BuddyBuddy

101 is different in Germany than it would be in the USA.
Europe uses ROM only for octane rating, while USA uses ROM + MOT (R+M/2) to get the AKI octane rating seen at the pump.
What that means is that a fuel with a 101 ROM rating only might end up being 93 after the MOT (motor octane) rating gets figured in.
The MOT rating tends to be much lower.
There is no direct translation or comparison available to easily compare the ratings.

95 ROM in Europe is the equivalent of 93 (R+M)/2 in the States. Rough estimate would be around 97-98 (R+M)/2 for 101 RON.

Originally Posted by MercForHire

Great info but there have been no reports of the knock sensors malfunction yet.
If someone has so little faith in every component of their e46 and is forced to use 91 out of fear. Then please, sell the German piece of sh1t.

You must be poor.

Please stop with the barnyard fantasy good ol' boy philosophy. If you can't afford to properly run your car, then sell your German POS.

Which brings me to my next point. Worst case scenario of premium fuel costs you $.20 cents more than regular, you're paying $3.20 more per tank for a 16-gallon fill-up. Can you seriously not afford three bucks a tank?

You'll also get poorer mileage on lower octane and less power (detect knock and pull timing as designed), if your car is specified to run optimally on 91 octane (like our cars are) So by one being a barnyard boy, one is actually hurting both their mileage and their wallet.

OP. following your owners manual is key.

Originally Posted by JohnIBarr01

Legitimate question: Anyone ever run 100 unleaded in a M54?

Yes

I ran a tank of Sunoco GT260 at Road Atlanta. Some day I'll fill up with it from a local station and record some data to compare against 93 octane.

I couldn't record data with my laptop while on the track.

actually what kind of gas you use significantly depending on your driving style. if you just cruising around at low rpm all day, probably regular/plus will serve you just as well as premium. if you like to hit the red lines and hear the engine sing like I do, premium is the only choice.
when engine is working harder, fuel is more easily to ignite we all know that. you surely dont want the fuel to pre-ignite causing a knock.
its like engine oil. why M3's with higher red line uses thicker oil to compensate the heat?

Originally Posted by BuddyBuddy

Although my "testing" over the weekend showed less than 1% difference between "regular" and "premium" gas, others have pointed out that there are other differences and they are basically correct.
Speaking only for the US, different parts of the country get different blends of fuel at different parts of the year.
In Chicago, we get a "winter blend" that always gets blamed for an increase in fuel prices.
When the winter blend is gone, it also gets blamed for an increase in fuel prices in the Spring.

After 10 years of driving back and forth between Chicago and Atlanta, I've noticed a marked difference (10% increase) in milage once I start filling up in Southern Indiana and parts south. I do not know what is different about the fuel, but I get better milage and it is cheaper.

There a many different blends of gasoline used throughout the US. Large urban areas like New York, Chicago, Houston, Dallas, Atlanta etc use a reformulated blend for reduced emissions.
Northern and southern states have different formulations of RFG. The Reid Vapor pressure varies based on the seasons. California has their own RFG requirements.

http://www.api.org/~/media/Files/Pol...ents_Map2.ashx

More general gasoline info from API:
http://www.api.org/oil-and-natural-g...ut-octane.aspx

I always got better mileage on the gasoline from Arkansas and Indiana than I did on the tank when leaving Houston on my trips to Indiana. Reformulated gas in Houston was the reason.

In Indiana there are still 4 different Reid Vapor Pressure gasoline blends used based on the time of year:
http://www.countrymark.com/documents...(03-28-12).pdf

Originally Posted by JohnIBarr01

95 ROM in Europe is the equivalent of 93 (R+M)/2 in the States. Rough estimate would be around 97-98 (R+M)/2 for 101 RON.

http://en.wikipedia.org/wiki/Octane_rating

Fuel	                                                        RON	MON	AKI
"regular" gasoline in  Canada and the US	              91-92	82-83	87

"Premium" or "Super unleaded" gasoline in US (10% ethanol)	97	87-88	92-93
Petro-Canada "Ultra 94" in Canada [8]	                      101.5	88	94

Sunoco GT260 Unleaded 100 AKI

Octane (R+M)/2 100
Research Octane RON 105
Motor Octane MON 95

Originally Posted by shanneba

http://en.wikipedia.org/wiki/Octane_rating

Fuel	                                                        RON	MON	AKI
"regular" gasoline in  Canada and the US	              91-92	82-83	87

"Premium" or "Super unleaded" gasoline in US (10% ethanol)	97	87-88	92-93
Petro-Canada "Ultra 94" in Canada [8]	                      101.5	88	94

Sunoco GT260 Unleaded 100 AKI

Octane (R+M)/2 100
Research Octane RON 105
Motor Octane MON 95

Ahh nice. Wasn't off by too much.

Originally Posted by mcaltinsoy

Hey everyone, i just bought my 330ci a few days ago. I always had japanese cars before. BMW seems like a different language to me nowadays. My question is it says on my fuel gauge Unleaded gas ... but anyone out there using premium at all?

They're all lying. You only need to fill your tank with soda.
Coke is best, Pepsi will kill your engine.

From personal experience 2 weeks ago on a 6000 mile road trip, I got the worst mileage of the entire trip when I put in 89 for a tank in my 320slow. I averaged ~28mpg when my 89 octane outlier of 23.2mpg was removed. All the other fillups were of 91 or above. The car also had a very noticeable power loss when attempting to climb mountain passes. (think floored in 3rd gear and decelerating at 60mph) I ran that tank down to almost nothing and the next tank was very noticeably different from a power standpoint - no more issues with mountains for the rest of the trip.
The 89 tank was driven with a slight (<6mph) side wind, so wind was not really a factor. I saw 30-40mph side winds through Nevada at possibly-higher-than-legal speeds and still got 25mpg on that tank.

At the cost of two tacos per tank over regular, I'm sticking with premium.