Twenty one pages of posts and I still have no idea what to do.

 

Well I guess you're right! mikem the OP, never did post again after the initial post back in September of 2005.
I guess after the back and forth battles of whether to use Premium or Regular the poor guy
must have decided to go out and buy something that uses Regular gas.

I still say decide for yourself... Go out and fill your tank with cheapest gas you can find and see how it runs.
Then go out and run at least 3 tanks of the highest grade gas you can find, then come back and tell me your MINI ran the same... I double dog dare you..

 

If you have an S, run premium.

or, read your owner's manual. I think most people that own cars never read their manuals. I don't get it, since a car is a depreciating asset and all.

 

did you miss the parts where people posted that you go longer on premium per gallon than you do on regular, that the car runs smoother and generates more power? If you skipped these parts, I'd see where your coming from.

Run the best gas you can get, it WON"T cost you any more money cause your MPG will be better.

Matt

 

Well, the problem is Matt there are plenty of folks who have found different and posted their results. Me, for example.

With an S, no question, high octane is the way to go. With a regular MC though, the premium isn't worth the extra money imo. I have done the 91 vs 89 octane test and the 1-2 mpg extra I got out of the premium wasn't worth the extra $.40 or more I was paying for it. Not only that, but 89 contains 10% ethanol, which is a darn good engine cleaner (just ask any alcohol dragster owner). And, ethanol makes a great gas dryer too, especially in the winter time when water is more likely to condense in your tank.

So, opinions differ. Best thing is to do your own research and testing and decide. Don't blindly rely on manufacturer claims or "recommended" fuels, parts or procedures. There are some who buy nothing but BMW parts, cleaners, etc. And there are those who do the research and quitely save their pennies.

 

so to help the math challenged, I made a couple of charts. One is based on a 1.5 MPG difference, one is based on a 2 MPG difference. If you want it for a 1 MPG difference, I'll leave that as an excercise for the curious.

They are color coded by price delta. FWIW, around here, the delta is 20 cents to 25 cents (10 cents from regular to mid grade, 10 or 15 cents from mid to premium). So I made three color bands. one is at 20 cents, one 25 cents, and one the 40 cents (ouch!) quoted by 2xMinis. top of the graph is cost of fuel per gallon for regular, verticle is MPG of your car using regular.

How to use the charts:

Find your price per gallon at the top. Drop down to your MPG using regular. This intersection tells you how much the MPG delta is worth at your fuel use rate and gas price. So heres an example. You get 2 MPG better with premium. Gas costs $4.00 a gallon for regular (still does here in NoCal). You get 25 mpg with regular... Then 2 MPG improvement is worth 32 cents per gallon. So if the delta between regular and premium is less than 32 cents per gallon, it will save you money to use the better gas.





This is strongly dependant on the delta (makes sense) the harder you drive your car the higher the delta will be.

Matt

 

I may not be math-challenged, but I'm definitely feeling "chart-challenged" after seeing your post.

How exactly is the chart to be read, and what is it telling us?

For example, if I use the "2 MPG delta" chart, and I find the intersection of the 30 MPG row and the $4.00 column, it gives me $0.27. What does the twenty-seven cents mean?

Or, should I be starting in the column that represents the price for regular gas, going down the column until I get to the row that represents the price delta in my area, and then going left and reading off the MPG figure? If so, what does that MPG represent?

I'm sure there's good information somewhere in the charts, but I'm at a loss as to how to read them.

EDIT - I think I figured it out. The numbers in the cells are how much more you should be willing to pay for premium, based on the cost of regular and your car's fuel economy using regular gas.

For example, if my car gets 2 MPG more using premium compared to regular, I should use the second chart.

Going to that chart, I choose the row corresponding to my car's economy on regular gas (let's say 30 MPG). I then pick the column showing the price for a gallon of regular gas (In my case, $4.00). The intersection of the 30 MPG row and the $4.00/gallon column is $0.27. That means that I can pay as much as $0.27 more a gallon for premium and still end up with the same or lower fuel cost-per-mile. So if I can get premium for $4.20, it's a good idea. But if premium costs $4.30 in my area, then it's not so good of a deal.

 

is the effective savings in dollars per gallon based on increased mileage. Sorry, I should have included that.

So if you get 2 MPG better with premium, and your regular fuel costs $3, and you get 27 mpg with regular, then the 2 MPG delta is worth 22 cents per gallon. I thought it was obvious, but then, I made the charts!

Matt

Really, if you don't want to log your tanks, assume the 1.5 MPG delta. Look at the intersection of your price for gas and your MPG. If it's a colored cell, then it's a good bet that you save money using premium fuel. FWIW, if you're within a few cents of one of the color bands, then it's still close to a wash (1% of the cost of a tank) and you might as well do it too.

 

OH MY!!! I feel like I was back at my SAT's! If it says to put in Super...I put in Super!!

 

Thanks for the charts Matt. Yeah, it took me a little bit to figure them out, but once you explained it, it makes sense. At my delta (gas is around $3.50 here for regular, and I currently get close to 30mpg with regular, around 1.5mpg better with premium), I save about $.22/gal, given that premium is about $.40 more. About $4/week at my mileage, or $208 a year. I figure in 5 years I'll save enough for a nice aftermarket exhaust.

 

1. If you're worried about 20 cents more per gallon, is now really the time to drop big $ on a car? Not trying to be a jerk- just saying!! haha

2. It's a MINI. It sips gas. It's not even an issue, really.

 

Here in the Chicago area, 93 octane premium is the norm. Sometimes I'll save a little money by getting a half tank or less of 89 to mix with my last fill-up of 93.

 

My 5 liter Mustang gets about 22 MPG, my modded Mini 24-26. I wouldn't really call that sipping.

Matt

 

Amen to that Matt. Had a stable of Mustangs myself, and even my best, a supercharged 503hp beast got over 20mpg on the highway and around 18 in town. I was kinda disappointed at my cabrio's mileage, premium or not. My wife's R56 though, that one really is a gas sipper.

 

I have an MCS with an ALTA intake, and I can get closer to 32-34 average- as long as I keep my right foot under control!

I was amazed- my dad has an '86 Corvette with a 350 V8 (Only 9,000 miles on this car!) and we were averaging 24 on the highway. Big engine + light car + aerodynamics= Not bad on gas!!

 

That's right! Big engine + light car + areodynamics and a 1300 rpm cruising speed at 60 mph = Excellent mpg's around 31 highway mileage on my husband's '98 Vette. (He still prefers a twisty road in my S, 'tho! )

 

best comparison i can offer is a non-mini example...ymmv.

1996 mazda mx-6 ls...my current car...183K+ miles...all but a couple hundred miles using 93 octane mobil one...all but a couple hundred miles were put on by myself...no major mechanical problems...bought new in 09/1996. biggest problem i ever had was this past winter, engine kept killing when in 1st gear going downhill...turned out to be bad gas. ran red heet through system, switched to 89 octane for a week or so before the weather got above freezing again, no problems since.

1996 ford probe gt (basically same car as mx-6)...co-worker's car...dumped before it hit 60K...always used 87 octane...always had mechanical problems of one sort or another...bought new in early 1996 (forget when exactly).

 

Or, take my former 89 mx6. Drove the cr@p out of it, always used the cheapest gas, and at about 180k miles became the official family fishing car (read, not treated nicely). Gave it to my little brother as a beater car at 206k miles, who used it as a, erm, beater and finally released it to car heaven with over 250k miles on the odometer. Not one single engine or transmission problem, still had the original clutch when it got retired (yeah, the clutch was shot at that point).

What I'm saying is you can't really compare longevity based on two samples, and especially when other variables come into play that are more important (like type of oil/filter, maintenance, etc). Engines nowadays run MUCH cleaner than say 20 years ago, so even on the worst gas, issues like carbon buildup, valves burning out, etc, are not nearly as severe as back then. I fully expect the average life of even a stressed 4cyl engine like in the MCS to meet or exceed 150k miles with just routine basic maintenance. Less than that I would definitely suspect assembly errors or parts defects... or insufficient maintenance, and by that I do not mean brand of gasoline nor additives used.

 

I know this is a long thread, and I did not do a search about my question!

So here it goes:

My local Sunoco stations just put a label on their pumps that they were using 10% ethanol in their product. I have been using their Super plus grade for years.

Will my 2009 MCS like this to make it go?

 

truth is, it's very hard to get gas without ethanol in it. Top Tier spec includes the requirement that not less than 8% to not more than 10% ethanol be in the gas. It's used to add oxygen to the burn to reduce smog, and the number of gas retailers that use anything else is very, very small.

Here in CA, you couldn't buy gas without either MTBE or ethanol, and now that the problems with MTBE have come to light, that means ethanol everywhere!

Matt

 

Times are definitely changing: my first fill on my 2009 MCSa yesterday, I paid $3.24/gallon for Exxon 93 AKI (anti-knock index). Regular (87 AKI) was marked $2.96/gallon. Today, at an off-brand station, I saw regular for $2.82/gallon.

 

Yup I paid the same for top grade gas today with a car wash. Regular was 2.99. Havn't seen it that low in ages. I hope it lasts.

 

A regular cooper needs 91 or better

 

Picked up my MCSa day before yesterday, read the manual. It says Recommended: 91, Minimum 87. Dealer said if put less than 91 in then should use an octane boost but manual does not say that, it just says you may experience start off knocking but it won't do any damage to you engine.

 

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