I’ve been poking around a little, and from what I can see the MINI Cooper S (the BMW version, not the Austin/BMC) requires a minimum octane rating of 91 – premium-grade gasoline. Is that true?
Yes, it does.
Sure…why not? Lots of cars made to squeeze extra performance out of their engines require high-octane fuel. That’s because the extra performance gains are often realized by using agressive ignition timing and/or high compression. To run on regular, they’d have to detune the engine enough that it would be slower. German manufacturers seem to have a greater fetish for making you use premium fuel than others.
I installed a chip in my car that requires me to use premium. That’s because it changes ignition mapping in a way that requires more knock-resistant fuel. The payoff? More power. I can run on regular, but the knock sensor in the engine will retard the timing to the point were I’m running in a stock configuration. Then I’ve got a $150 chip under the hood not doing a damn thing.
Bummer. Sort of negates the entire concept of the original car.
If the extra (in my case) 10 cents/litre is stopping you from owning a ~$24000 car ya might not be able to afford said car.
I thought the same way before my Matrix but in the end, the extra 10 cents (or for you guys I assume 40 cents) doesn’t make a huge difference. I already spend $3500 a year in gas. If I bought regular I’d be saving a whooping $270 a year give or take. Not a huge savings either way and I get to own a 180 HP (the Mini-S is 160 I believe) Matrix XRS that gets ~30 mpg if I don’t push it (or about 20 mpg if I do :D) Cheaper than using regular in a V6.
You can use 87 but you’ll loose a lot of power. A friend of mine who’s a Toyota mechanic uses regular in his XRS that his wife drives.
Not looking to buy a new car now. I have to finish getting my MGB restored. (And I’ll be driving the hell out of that! 
) I was just curious, since the idea behind the original Mini was economy and requiring premium fuel in the BMW version seems to go against that.
The BMW Z3/Z4 also requires premium fuel; I assume it and the Mini Cooper are pretty similar.
Just one of the several ways the Cooper is more BMW than Mini.
Usually it’s an upcharge of $.20US/gal. For example, my last fill at the pumps, I noticed the prices were $2.09, $2.19, $2.29 / gallon for Octane 87, 89, 92 respectivly.
I also have a chip in my '98VW (190K miles), and notice it does run better with the premium, I also get a couple of MPG more with the higher octane fuels.
The net per fill is about 2. (.20 x 10gal) More for a bigger tank, or less frequent fills.
The “S” version is not the economy version. Does the standard version require premium gas?
Yes, it does.
I don’t think BMW knows how to make an engine that doesn’t require premium fuel.
‘Require’ is a relative term – just because the manufacturer recommends a particular octane doesn’t mean the vehicle won’t work with less. As long as you aren’t getting ping or knock, your octane is OK. Try a lower octane – you might be pleasantly surprised.
You can also try mixing octanes, or even mixing lower octanes from different vendors – different refineries use different methods for raising octane, and some combination may prove to be perfect for your vehicle.
The problem with that is what was discussed above. If you use lower octane gasoline, you may force your ECU (engine computer) to retard timing. Robbing you of some of the power available in your engine. If you’ve the fancy tools, you could check this under load (acceleration), but since he’s asking the question in the OP, I’d assume he doesn’t.
Manufacturers don’t recommend a particular octane just for the hell of it - high-performance engines are designed with the expectation of being fed high-octance fuel. They can compensate via knock sensors and the like if you give them 87, but this is not foolproof. If the sensors fail, you’re out of luck.
Also, the changes the ECU has to make to accomodate the lower octane fuel affect the power and efficiency of the engine. Generally, the money you save by skimping on gas is more than lost again when you consider that you have to stop for gas 25% more often.
Wait, the 115 hp version needs 91? That’s pretty weird. The 140 HP 1.8L Celica and 130 hp/I4 Matrix and Corolla (same engines in all) don’t need that!
But you are right. Using 87 where 91 is recommended will rob you of plenty of mileage. I personally won’t skimp on a 10c difference in gas (you guys get premium for cheap! 20c difference? Sheesh).
I’m sure this has been asked and answered before, but since it’s on topic, sorta, I’ll ask you motorheads:
Why so low octane in the US? In Europe, it’s 95, 97 and 98. Or is it just different labels for the same stuff?
And WRT the Mini: It’s not an economy car. It’s a toy, meant to be driven like a race car. The S version will not fly, but when you’re driving it, it feels like it’s got the ability. Tremendous fun.
I have never consdiered the mini to be an economy car.
I’ve been using 87 octane for the last 60,000 miles of my car. One of the reasons I decided on the car was because for the 2001 model year, one was no longer required to use premium fuel. I remember reading that for 2001, Ford added an anti-knock sensor specifically to allow the use of lower octane gas.
I’d done mileage comparisons – I get about 2mpg more with premium gas. In another thread here I posted the results and cost comparison, and decided that it wasn’t worth it.
But now – I just downloaded the owners manual, and it doesn’t mention a thing about gasoline under 91 octane. Looks like I’m NOT supposed to use it. I thought, though, that “premium only” cars had that written near the fuel gage – or is that only rental cars (with the little “fill on this side” arrow).
Even with 87 octane, though, the car’s a sleeper – fast as hell and you don’t expect it because normally only fedora-wearing old people drive 'em. As the car gets older and older, maybe I ought to treat her once in a while. Especially in that I’m not using it all that much now.
A quick google search shows people claiming 40 mpg (1963, 1966). This site says:
To me, that fits the definition of an ‘economy car’. By extension, the BMW MINI should be an economy car. I can (somewhat) understand the relatively high price, but the lower fuel mileage and need for high-octane fuel is the antithesis of the original concept.
Regular fuel is 87 octane, mid-grade is 89 octane, and premium is 91 or 92 octane.
My 600cc bike runs on 87 octane (unless it’s a hot day) and gets 50 mpg. My 1000cc sportbike requires 91 octane and gets 40 mpg.
Different measuring methods/scales, so basically the same thing with different labels. Though there are probably different gov’t requirements between the EU and US (like lead, etc) the octanes available aren’t really much different.
I agree, no one I know who owns a Mini bought it for economy.