Well, the Porsche manual you quoted still lists 90 AKI as the absolute *minimum* octane rating you should use, and for many parts of the country, that means that premium is the requirement. If the knock-detection system could correct for lower octane than that, they'd probably allow you to go all the way down to 87.

The MINI R56 manual, on the other hand, *does* specifically okay the use of 87 with the explicit statement that it won't affect engine longevity.

 

Are you both done now?

If you two can't have an intelligent conversation I'm locking this thread and putting you both on moderated posting. Meaning each post you write will need to be approved before it will show, and with almost all the staff at or on the way to MOTD posts won't be approved for about a week.

 

I gotta agree with gnate here. This has digressed way too far.

My apologies to Krieg, and the forum at large. Remember, kids: arguing on the internet is like using steriods at the Olympics...even *if* you win, you're still a loser

 

My apologies too. I wanted to state what I thought was a sensible point and then let my ego run away.

 

I'm not taking sides although i use premium... but really, how do we know whats coming out of the pump every time we gas up? I saw a news story a few years back that showed an alarming number of gas stations pumping regular gas WITH PREMIUM SIGNS..

 

I always use premium top tier brands in my Clubman, but I also put some Redline in the tank about every other fillup. I read that it is recommended along with the premium top tier brands.
I had used the premium gas from Costco in my BMW, but after finding out that they use the cheapest brand available I switched Buffy to the top tier brands, too. The cars deserve the best.

 

I agree, Nomad. My current tank of premium is behaving like regular.

 

wow,
according to the above, most of the major name brands are "top tier". Why is 76 always much cheaper than Shell, Chevron, and Mobile?

TOP TIER Gasoline Retailers:
QuikTrip
Chevron
Texaco
MFA Oil Co
Conoco
Phillips 66
76
Entec Stations
Shell
The Somerset Refinery, Inc
Kwik Trip / Kwik Star
Aloha Petroleum
Tri-Par Oil Co.
Turkey Hill Minit Markets
Mileage Stations
Chevron Canada
Shell Canada
Petro-Canada
Sunoco Canada

 

Also, some people will recommend "top tier" gas, while also advising you to stay away from gasoline that contains ethanol, not realizing that it's impossible to do both.

One of the requirements for "top tier" status is that your gas must have AT LEAST 8% and no more than 10% ethanol, in *all* grades (regular, mid-grade and premium), at *all* locations. It's right on the top-tier website.

 

I can't decide what to do . Every time I am at the pump, I stare at the three selections for 5 minutes and throw a coin. Sometimes the coin goes in the gutter and I lose the coin. Then I go home without pumping gas... I have run out of gas because my coin rolled under another car and could not safely retrieve it and I drove home anyway. Please tell me what to do~~~

 

MMMMMM.... Do you get a free half gallon of ice cream with a fill-up?

 

The topic of octane tends to get pretty ugly at times. It's your MINI and each of you will decide what type of gas goes in the tank.Anyway on with the discussion......

 

It seems a good time for a reality check. The spread between regular and premium is around 20 cents a gallon. That's $2 to $2.50 a fill-up. What's that over a year? $100? $150? No, it's "chickenfeed."

 

I fill up every 350 miles, I drive 20 miles/weekday. That means I fill up 3 times every two months. = 18 times/year. 18x2=$36/yr.

 

all stations around here have the ethanol mix......what brands do not have ethanol mix in the Northeast?

 

I did a factory delivery on my BMW and when I asked about break-in and fuel requirements, the representative I talked to explained to me "follow the break-in to a T if you are going to keep the car but save your money on the premium fuel unless your going to the track".

I can honestly say I have never put premium in any of my rides, even when going to the track. One vehicle is going on 5 years now (original owner.)

 

First, I am NOT a gearhead. But, I am technical and this stuff isn't necessarily rocket science.

It stands to reason that pinging/knocking may only occur if the temperature/pressure in the cylinders is sufficient to cause premature fuel ignition. Clearly this can and will occur when the engine is pushed and fuel isn't "up to spec". I would submit that pre-ignition is extremely unlikely to occur under a certain sustained maximum engine rpm load.

Let's please say for discussion, that this magic # with zero effective chance of pre-ignition is 2500 rpm. Please note: if you would like to bite my head off on this, please don't do it here - I'm trying to have a discussion along certain lines, not have a detailed diatribe back to "do what the manual says" vs. other methods.

We may ALL agree that 87 fuel is somewhat "less efficient". What might be interesting for us to SHARE with each other is real-world data on fuel consumption.

So, my real question is under light engine load for a R56, what real world measurements do we actually have as to fuel consumption for 87 vs 89 vs 91?

PLEASE specify your year, make, model, Transmission, and color (I'm planning to skew the results in favor of Pure Silver).

I'd like to collect this info and see if there are any interesting trends in the data.

Jeff

 

I get 31-32mpg around town and just over 34 on the highway, calculated by hand, with most tanks being regular 87 and the occasional premium tank. That's an '07 MCS with just over 22k miles.

 

I have lever let a single drop of non-premium gas in my 07 MCS knowingly. If the gas station lied and sold 89 OCT gas as 92 OCT then I might have but I don't know that. I get 31mpg mixed.

 

Ethanol is garbage...my MINI hates it.

 

Thanks for your response. I bought my Mini in July 2008 and have been wondering what would happen if I used less than premium grade gas. I'm sick of reading these sanctimonious posts by people who always use premium gas and lecture on about it. Even more insufferable is their obsession with buying gasoline only from certain outlets. I don't know if there is really much difference between the different brands of gas. My friends who work in oil refineries don't think so. I do know that I have more important things to do in my life than worry about which brand of gas to use.

I want to hear from more MINI owners who are using 87 or 89 octane. Here in TX the premium is 93; they don't sell 91. I only get around 32 mgp using 93 octane fuel. I drive a Copper, not sport model.

 

Wow only 32? Is it auto? Mostly spirited runs?

 

I drive a Cooper as well. I used regular once so far, but I think I'm going to try it next time, since I'm getting good mpgs with the CITGO premium I've been using. The time I used it I seemed to get a few less mpgs, but it was a different brand. It also seemed a little less peppy, sort of a slow start, which you would expect if the spark was retarded. It's all so subjective though. I thought one tank of premium at a convenience store out of my normal area got low mileage, but that could be because of the ethanol. It also did seem to be less peppy, so who knows what I got. The regular I'm going to try is ~22cents less than high test, so it doesn't really amount to that much $3+ or so per tank.

 

No I drive a manual. It does get better with pure highway driving, but not by much. With a 13 gallon tank, the car gets refilled after a mix of city and highway driving so I've never been able to measure strictly highway mpg. I think the best I've calculated is around 34 or 35 mgp.

I've been a little disappointed given the 40 mpg they advertised last year. The EPA or some gov't agency has forced all the car manufacturers to post more realistic MPG ratings. Have you noticed how now MINI advertises 37/28/32 for the MC standard transmission?

After driving a Chevy Prizm (same engine as Toyota Corolla), I do confess to enjoying the acceleration of MINI engine. Perhaps my mileage would improve with more patient driving on my part . But I am getting MINI's currently advertised 32 combined mpg. I prefer my more peppy MINI engine over the more fuel efficient of my old Prizm.

 

Use the techron valve cleaner once a year. That will keep the engine efficiency up also.