I'm not a chemist and am not an expert in this area, but here is my understanding: Some cars need higher octane in order to prevent engine knock. For those cars at high altitude areas, it's completely fine to use the low-grade gas instead of the recommended mid-grade.

The Mini, however - I don't really know. I'm also in a high-altitude area (Utah) and just use 91, which is the highest available. I figure with the Mini's high compression engine, the turbo on the S, and Mini's recommendation all say use premium. So I do.

 

no comment here (I use premium in all my MiNis because that's what the book recommends) but an observation

- MINI recommeds something that costs the owner $$ like using the most expensive grade from only top tier, aka main line and usually most expensive, suppliers and they are steadfastly supported referencing 'the engineers know what they are doing'

- MINI recommends something that saves the owner $$ like extended interval oil changes and they are accused of intentionally trying to get us to ruin our cars for their potential increased profits. 'The engineers are idiots.' Recommended solution: spend your $ on more oil changes.

Interesting....the common thread is if it costs us more it must be good. Capitalism is winning

**************
side bar - a practical discussion of octane and what it means to us

as a post above says, OCTANE has to do with the 'explosiveness' of fuel and the higher the octane the more resistant the fuel is to explode. YES RESISANT.

If your (our) vehicle is designed to run on 89 octane .... and you put in 110 octane .... it will not run better, unless your car has a problem to begin with. That extra octane just means your car absolutely positively waits for the spark plug to fire. As it would have for 100, 90, and 89 octane. Think of it as the car is designed for 89 and anything more is WASTE.

if your car is designed to run on 92 and you put in 89 on the other hand...compresssing the mix CAN cause detonation B4 the spark. This is called pre-ignition, or knock.

In the olden days when high octane became unavailable {late 60s, early 70s; first major gas crunch} but we had cars that needed high octane, we "retarded the spark" which means we changed when the spark plug fired and made sure it happened before the 'knock'. By doing this we lost power because the fuel compression was lower than design ... but the car ran smooth. Today's cars? yes MINIs - do this thru the computer and if you run too little octane the computer simply down tunes the car (aka retards the spark) and you loose power as the computer tries to compensate for YOU NOT FOLLOWING THE RULES


class over

 

I don't buy it. I would use premium as the owners manual directs. The vehicle's ECM (brain) should compensate for the altitude.

 

I'm running Chevron 94 because its the only stuff in my area that's ethanol free

 

I too live, and have lived for decades, in a relatively high altitude place (Boulder, CO). During these years I've regularly asked any seasoned veteran motor-head I come across about the effect of altitude on a hi-perf engine's need for octane; probably about six or so folks plus about two editors of auto-enthusiast mags (Road & Track and one I can't remember). All of them have quickly and unequivocally said that the higher the altitude the lower the octane needed and that doing such has absolutely no harmful effect on the engine. Even the original dealer in this area (a new one just opened last month) has said, as was noted above, mid-grade should be fine.

HOWEVER, the trick is that no one has provided or guided me to an exact formula the specifies how many octane units can be decreased per increased foot in altitude. So, it becomes a trial and error game. As a few folks in this string have mentioned, they prefer to go by the book, but for the others of us who have a comparatively higher pain response to the greater costs of the higher grade fuel, there seems to be a substantial amount of valid evidence that at 5000 feet and above, feel free to experiment.

NOTE: Blindfully following my prior abilities to run hi-perf engines on "regular" at this altitude without any negative outcomes (most recently my Passat W8 - 8 cylinders), when I did this with my 2010 JCW, I experienced randomly occurring failures to start when the engine was cold (8 or more hours). Since switching to mid-grade 4 months ago the problem hasn't occurred at all.

 

93 in my MC since day 1.

 

Higher octane than the engine needs makes less power. If your turbo is making 25 LBS of boost, 98 octane may be good. Although my Sky turbo made 23-25 Lbs of boost and I used 93 octane.

 

I thought you were kidding at first. How do you overlook the current debacle, and point to their "overall environmental record"? When you screw the pooch as badly as they did in this case, I'd say that pretty well renders your prior record meaningless.

 

WOW

 

Who should I buy from then? Shell? Exxon?

Deepwater Horizon is the worst spill ever. But what we can see of BP's daily worldwide business practices show them to be the best of all the Big Oil companies. I fully expect new rankings to be announced within the next year. We will all soon see how big a hit BP takes whenever that is. Maybe this tragedy will bump someone else to the top of the list?

My MINI is thirsty. I must feed it. Ergo, I prefer to shop the most responsible Big Oil company I can find. *shrug*

 

Actually, it is not the worst spill ever. This link leads to a slide show from CNBC that lists the worst spills. This spill has the potential to be the worst but is far from it to this point.

http://www.cnbc.com/id/36851250/

Pat

 

Ah, very true. Thanks for the correction.

 

You're right. We have 94 Octane Ultra Gold from Sunoco. I live in a small town in Ontario and we have two Sunoco stations serving up the good stuff. It's awesome, and I don't mind paying extra for it. I average 45mpg and my Engine is not even broken in yet... combination of highway and driving in town.

 

Not sure why you are asking about an '02 in the 2nd Gen Forum ('07+), but I use Shell 91 (California highest readily available). Had problems with BP gas in another car, so I stay away from it.

 

45 mpg. Is this the imperial gallon?

 

That's what I was thinking. My wife's car with an automatic is getting about 30.5 mpg on mostly highway driving. I get about 31.5 in my car that is a mixture of highway and in town. (I drive fairly aggressively) I calculate the old fashioned way. The cars computer calculated too generously on both cars so we don't use that data.

I wish I got that kind of mileage??

 

Because the OP just traded in the 02 for a 2010.

 

same...

 

93 octane either Mobil or Shell - most recently at $3.459 a gallon (ouch!!). Does anyone have a list of top tier producers?

 

BMBULBE: Check out the following web site:

http://www.toptiergas.com/retailers.html

 

BP or Shell 93 Octane only!!

 

Havent gotten my Mini yet but for sure will be loading gas on Petro Canada 94 octane fuel. You wait so long for the car, why not treat it right?

 

91, It's the highest we get in Cali without having to go to specialty places. My BMW required 91 also so to me it's no big deal.

 

I use the highest octane my buddy carries, 93. DO NOT USE THE 87 octane.

 

This is true. But you should still us 91 octane at your altitude. Your car will run better esp. in the summer when higher octane is a must.