Yes, I know the manual specifies 91 octane (right?), or at least "premium." It says the same in the manual for my non-S Clubman. The dealer assured me that mid-grade would be fine, and it has been for 103K. I put one tank of regular in, and it ran for crap. I've run the numbers, and between the cost of fuel and the low MPGs of the "S"models, the "S" would cost me ≈$270 more a year to fuel than a Justa CTM. (The big comparison is that a CTM-S would cost $525 more a year for me than the paid for Clubman...)

The numbers can be pushed all over the place, and the big variable is really how good my real world mileage would be in a CTM or a CTM-S.

But, I was just idly wondering if anyone had run mid-grade in an S, with either positive or negative results. Thx!

 

The Countryman is going to cost you a lot more than $225 vs the Clubman in gas because it's less fuel efficient.

The cost difference of mid vs premium isn't worth potentially damaging your engine.

 

The manual says for the JCW recommends AKI 93 but I once used 91 with no noticeable difference. My dealer insisted that I only use gas from quality gas stations like BP and Exxon (which is also states in the manual). I thought all gas was essentially the same. That said when I use the 93 AKI from Sam's Club vs. Exxon I seem to get slightly worse MPG with the less expensive Sam's gas. Of course that may be simply the way I drive. I have not tried the mid grade Min recommendation of 89.

From the manual:
The engine is knocking regulated. Therefore, different grades of gasoline can be used for refueling.
Recommended gasoline grades:
The manufacturer of your MINI recommends:
> AKI 91.
> John Cooper Works: AKI 93.
Minimum quality: The manufacturer of your MINI recommends AKI 89.

Do not use any gasoline below the specified minimum fuel grade. Otherwise, the engine could be damaged.

If you use gasoline with this minimum AKI rating, the engine may produce knocking sounds when starting at high external temperatures. This has no effect on the engine life. The use of poor quality fuels may result in harmful engine deposits or damage. Additionally, problems relating to drivability, starting and stalling, especially under certain environmental conditions such as high ambient temperatures and high altitudes, may occur.

If drivability problems are encountered, we recommend switching to a high quality gasoline brand and a higher octane grade - AKI number - for a few tankfuls. To avoid harmful engine deposits, it is highly recommended to purchase gasoline from BP or Top Tier retailers.

Failure to comply with these recommendations may result in a need for unscheduled maintenance.

 

My dealer says run the top grade stuff in it, he went on further to say use gas from SHELL, not from any one off places.
My dealer said that running the pricey stuff will help keep the carbon build up on the valves from happen as fast and says to throw some gas additive cleaner in the tank a couple time over 3 to 4k miles.

 

My dealer said no issues with running Mid-grade, actually preferred, so that's what I've been putting in it. ~10k miles and running like a champ. Any reason to upgrade to Premium at this point?

 

Penny wise and pound foolish!
Lower octane = lower efficiency = lower mileage
Lower octane = potential engine pinging = catastrophic engine damage including damaged ping sensor. Had that replaced for a sum total of $460.00


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

 

If you do a lot of city driving, stop and go, that will also hurt you if you are using cheap gas/lower grades. If you are one of these drivers, take it out the HWY and drive it for a bit to blow it out some.

 

The carbon build up thing does not happen over night and at 10k you prob are still a bit out from having carbon related issues. My dealer said that it is just going to happen and to put it off run some cleaners through the gas tank time to time, and put good top grade gas in it.

 

I *do* avoid one-off stations and places like Sam's, Walmart and Costco for gas. I have nothing other than anecdotal reasons for doing so. But I suspect that my logic is no better than the dealer's saying run the "top grade stuff." If the dealer were that knowledgeable, it seems to me that he would say buy one of these brands of fuel. Some fall back on the "Top Tier" thing, but if you Google "Top Tier Myth," you'll discover another answerless internet discussion.

Folks report better MPGs with premium; I found no difference on the few tanks of that I've run. There's as much variability between stations as between grades in my Clubman, in my experience.

So, I know I was risking firing up this discussion, but I wanted to see if anyone had run midgrade (not regular) without adverse consequences. Feel free to PM me if you don't want to encounter the static.

 

Just stick with 91+ octane so you don't get knocking. Better to be safe then sorry.

 

I have a thought, and please someone correct me if I'm wrong, with the direct injected engines carbon deposit will happen with any fuel you use (grade, brand, octane) and it will happend at about the same rate. The reason for the carbon build up is due to the lack of fuel running over the intake valves since the injectors atomize the fuel directly into the combustion chamber, thus skipping any cleaning that would happen with fuel going into the intake and over the valves. The same could be said about any fuel cleaner that gets dumped into your fuel tank since that cleaner follows the same path as the fuel.

The lower the octane rating the higher the risk of knocking. Now knocking can be very minimal to completely destructive. There really is not way to be sure where the cut off is without trying each octane for a very extended amount of time (tens of thousands of miles) and when you've found out which octane level is the on the destructive side, it'll require a rebuild or replacement of your engine. I'm sure we can all see how that is a very large risk to take in an attempt to save a little cash.

All of this of course is not taking any fuel economy facts into account. Or the fact that there is a performance factor involved. You achieve lower HP figures with lower octane rating.

 

seems like a design fault if nothing is hitting the back of the valves.

 

This could be argued endlessly either way. Yes, design flaw since carbon build up happens. No, because it wasn't designed to have fuel flow over the valves.

Basically it boils down to extra maintenance. You should have the intakes cleaned every 30k minumum. This is one of the reasons people opt to have and oil catch can installed(several other reasons of course).

Some people use seafoam. Others use chemicals. Walnut shell blasting is becoming popular. One option that would clean and add temporary power is a water/meth injection system. That would keep the intake clean forever, so long as you use the system properly. Plus a water/meth system can add HP, not too unsimilar to a nitrious system.

Either way you cut it, this is how a direct injection (DI) engine works. And this isnt just MINI's DI style engine. Many others use DI engines now such as Mazda, VW, Volvo, nearly everybody. Perhaps later with advancements they may find a way to route extra fuel to clean the valves without hindering fuel economy. And maybe they have and I'm just not aware. Remember this engine design started back in 2002 as a joint venture between BMW and Peugeot so its not exactly state of the art.

 

Well, I did learn a couple things: 1) that the S engine is direct-injected, and 2) the bit about valve deposits in such an engine. Compression ratio is only 10.5:1, but that's out the window in a turbocharged engine, so spark knock is a bigger issue than in a NA engine.

Does anyone else find it somewhat surprising that a knock sensor would fail due to...knock?

 

Same here, good brand gas, 91 octane. It isn't just about mileage. There are a lot of lightweight materials in that motor, definitely aluminum, perhaps magnesium (unable to confirm if the Mini motors have any magnesium parts) and the lower grade gas will wear on these parts more in a high compression turbo motor, so you may not see issues initially, but in the long run, well, you should save your gas money you are saving 10¢-20¢ a gallon on and save up for repairs.

 

Just one of the joys included with the prince engine.

 

Isn't this only an issue with the N14? I've seen threads on catch cans with the N18 and the buildup issue has been severely mitigated, to the point that the average owner may never need to have them cleaned. Though in fairness, I don't think any N18 owner has had theirs more than 3 years, but there are definitely high mileage cars with the N18.

 

~$200 in savings for premium gas? That's not much at all compared to a new engine.... Just fill it up with the good stuff. Saves you the trouble of worrying and protects your baby.

Kyle

 

I had this CM for 18 months, it has 12400 miles on it have run just 89 octane in it no problems and thats what the dealership filled it with when I purchase it. the engine does not ping. And I've used hess, irving, gulf, and shell gas. the worst milage I got was 29 But had my foot in the throttle a lot, the best I'vs got is 37.5. With this mini I can be on a flat stretch of road in 6th doing 34 step on the gas doesn't pick up speed very well but I'm just cruzing, speed limit is only 30 but the motor doesn't ping knock rock or anything just smooth. even my owners manual says 89 octane. this mini is not the jcw model. Just 2 wheel drive. and I love it. I have dumped a can of sea foam in the gas tank last summer and will probably do it again next summer. I don't kmow if I needed to I just did it. I would just go with what your manual tells you.

 

Put the good stuff in , don't be cheap . This coming from a SD driver lol