There seems to be lots of discussion about what octane to use in the Mini. I know a few owners that use 87 and just add the additive sold at Walmart but is this safe? Should I be using at least 89 when I pick up our Mini? What's the deal?

 

If you open gas cap and it says premium gas only then I would use 91 or better. We have 93 here in Ohio and that’s all she gets.

 

Most of the additives don't do much. People need to read the fine print and see how little they raise octane levels. Waste of money IMO. I always use Premium in MINIs.

 

I have a 2019 MINI Cooper S. Does going past 91 have a benefit?
Like if your car only requires 87, giving it a higher octane isn't better for it.

 

I can’t see a MCS not taking premium gas. Maybe the base models, but I’m pretty sure if you have any form of boost it premium gas.

 

...and then of course there’s the Top Tier gas discussion. I personally have always used (and switched back and forth between) BP and Exxon 93 grade in both MINI’s. My 2012 hardtop at 50K miles just received new coils and plugs. My 2012 Countryman S All4 needed coils and plugs before the warranty expired at just over two years. Two MINI’s are a mighty small sample, but it’s my reality!

 

good video on the topic


"If you’re scratching your head wondering which number gasoline to put in your car, don’t overthink it. Just Google the manufacturer’s recommendation and run with that. If you’re curious about what those numbers mean in a practical sense, check out this video. .... Car YouTuber ChrisFix seems to be branching out from his usual “how to repair something” content into somewhat broader topics, and this video explains why higher octane gasoline isn’t necessarily better and it doesn’t store more energy.

Octane ratings are about knock resistance, not explosive power. The higher the octane rating, the less likely the fuel is to prematurely detonate. But as long as your engine’s running correctly, that’s only a possibility if the engine’s designed a certain way. Typically, with a turbocharger or very high compression."


near the end of the video he discusses 'required' versus 'recommended' on the manufacturer octane requirements.

For the record here's what a selection of owner's manuals said (all available on line in pdf)

2002 S
Required fuel:
>Premium Unleaded Gasoline,
min. 91 AKI.
AKI = Anti Knock Index.

2014 (2009 had same)
Gasoline quality
The manufacturer of your MINI recommends:
▷ AKI 91.
▷ John Cooper Works AKI 93.
Minimum fuel grade
The manufacturer of your MINI recommends
AKI 89.

2019
Recommended fuel grade
MINI recommends AKI 91.
John Cooper Works:
MINI recommends AKI 93.
Refuel with this gasoline to achieve the
rated performance and consumption values.
Minimum fuel grade
MINI recommends AKI 89.
John Cooper Works:
MINI recommends AKI 91.

My last two cars were 'not MINI' but with similar 4 cyl' turbocharged engines. In both owner's manuals they listed regular as fine but had a discussion of when to use premium and the tradeoffs. Maximum HP does require 'premium' as the engine 'de-tunes' to accommodate the lower octane. The MAX HP difference in one case was 3% and in the other a potential of 10% maximum. Both mentioned that driving under heavy load, such as towing - steep inclines - or heavy foot, the use of premium would be recommended to prevent knock .... as explained in the video.

 

I got a pesky p0420 code that was popping up here and there when I first got the car in November, 200 miles into ownership, I put some Speedway 93 in and a bottle of Redline fuel system cleaner, which was probably a waste of 15 bucks. 400 miles later same light. Every since I have switch to BP, Exxon, or Shell 93 light is gone, 1500 plus miles so far. The light would come on and turn off after like 20 miles or so. Mine my just be a picky little PITA but she’s my PITA 😉

 

video discusses the 'top tier' issue as well

popular opinion is there IS a difference with regard to detergent/cleaner additives in various brands and he even mentions SHELL premium as having 7 times the amount of cleaners as their regular and their claim that if a develop knock in an engine not requiring premium ... running SHELL PREMIUM for 2500 miles can clean a significant amount of crud out of your engine. (but SeaFoam folks claim one can of their stuff will do the same thing soooooooo)

I'm a fan of running top tier regular most of the time and avoiding problems via cleaning agents. I don't have a heavy foot (very often)

*******
old school: My 79 has a higher compression engine than typically seen today and ZERO computers. If I put anything other than 91+ in it, I know FAST. The engine will knock like crazy under the slightest load and often will diesel with the ignition off (key off & engine keeps running .... mechanical fuel pump will keep sending fuel .... compression alone will ignite the fuel.) I learned this early in ownership with one tank of 'middle' and have had it be a truth serum for small gas stations claiming to sell high octane ethanol free. Curiously my engine ran the same as when I had low octane fuels and a return to an chain station with 91+ even with ethanol solved the problem .......

 

Also depends upon what altitude you are at. The highest rated fuel at high altitude is 91.

 

I have a 2015 Base Cooper, but it still has a turbocharger. It says right in the gas cap area to use 91 octane, so that is what I do. Why take a chance? You will see the same message when you open your fuel door. Why risk damaging the engine, to save a few bucks on a fill up? That is just silly!

Kat

 

And just for a reference on that, aviation gas is 100.

 

There is? Go ahead and run lower octane fuel than the vehicle calls for and see what happens.

There is no way a forced induction engine is running 87. The car would have to retard the timing and cut the boost just to run, and it would run like garbage.

And still leaded!

 

Basically what i was getting at, if you have boost, turbo or supercharger, then put the best gas in you can.

 

Hard to compare octane of aviation gas vs. pump gas as they use different measurement systems. But 100LL aviation fuel is definitely higher octane than any pump gas you can commonly buy. But, despite it being labeled "low lead", it has way too much lead to be used in any car with a catalytic convertor and even in a catless car, it will cause problems pretty quickly with lead deposits and fouling. (There is a good reason aircraft engines typically require regular 50-hour plug cleanings whereas a modern car engine will often go thousands of hours on a set of plugs with no cleaning whatsoever.) And aviation engines are totally different animals from car engines with very low specific-power (i.e., hp per cc) output, very low RPM, constant high-power settings, and huge cylinders. All these things make 100LL a poor choice to use in any car. It's also illegal, at least in the states.

In virtually any stock car, I run what the OM and gas filler door say. While you might get a little more power (for engines which adapt to higher octane - not sure whether Mini's really do) or perhaps a little better additive package with premium, it isn't worth the extra cost to me. If you're really worried about deposits a can of Techron every few thousands miles will likely do a much better job than running any particular gasoline.

- Mark

 

 

I've ran 89 octane for years with the occasional 91+ fill up. Engine ran fine on it.

 

That was solely interjected on the basis of altitude. There's a few other aviation propulsion considerations totally unrelated to MINI operation as well. One quiet night aloft a sudden rough engine brought me to attention. It took a moment to think of examining a rarely seen indicator, carburetor temperature. Turned on carb heat and things smoothed out nicely. I don't ever remember a MINI person on NAM reporting a problem with carburetor icing.

 

These cars require 91 octane, even the base model. In my area, premium gas is rated 93, if they sold 91 here and it was cheaper, I'd be using it. Going to 93 will not give you any benefits. Your ECU will just compensate for the higher octane. If you got a tune that locked in 93, then there would be some benefit.

 

did you bother to read my post (#7)?

GEN1 cars did say

Required fuel:
>Premium Unleaded Gasoline,
min. 91
your car is GEN 1, R53 so for YOU this is a correct statement but for the majority ...

After GEN1 the wording changed .. I pulled straight from the owner's manuals .....

The manufacturer of your MINI recommends:
▷ AKI 91.
Minimum fuel grade
The manufacturer of your MINI recommends
AKI 89.

which is what you see in the picture on post #16 . . .

 

"Premium" is a marketing term designed to extract maximum reimbursement from the pockets of those that don't know what it really means. "Premium" is NOT a designation of quality, it is a designation of resistance to ignition.

Not all "Premium" fuels have more detergents than the non-premium fuel in the pump adjacent to it, but, some do. MORE detergent than is needed isn't great if you are looking for more power, because Detergent IS NOT FUEL. Of course, more power can be possible with a higher Octane-rated fuel, but, the engine/ignition system has to be designed to be able to take advantage of a delayed spark input made possible by that higher-Octane-rated fuel...as most modern Turbo and Super-charged systems seem to be designed.

All that said, if you gently run an engine with a relatively mild base compression ratio that doesn't get into the higher compression range until the turbo- or super-charged boost is substantial, you will be fine running a high-quality "Regular Octane-rated" gas, since you do NOT get into the higher-compression situations that require the more-resistant-to-premature- combustion higher Octane-rated gas. MOST of the turbocharged engines in standard cars even allude to this, with statements such as: for maximum power, use the highest Octane-rated gas at the pump, or; use at least 91 Octane-rated gas (depending upon the country, as different countries rate Octane in different manners).

Octane ratings are not based upon a feeling, nor belief, it's based upon well-known science...if people care enough to actually do the research.

 

umm, was my post in answer to your Whole Entire Post that I did read in it's entirety.

 

Based on feedback from the forum, I use Shell VPower whenever possible. Since the nearest Shell is 20 miles away, I have occasionally had to buy 91 Octane gas from the local non-branded stations. The MINI runs rough on anything other than the good stuff.

 

As a few have posted and even from one of the above pics I opened up the gas cover of our new Mini and yep minimum 89, recommended 91. So I'll be running the minimum with 91 being the occasional fill up.

 

Yeah I think I’ll stick with the 93 and the extra 3 to 4 bucks per tank to keep that damn p0420 code away. Haven’t seen it in over 2000 miles since switching to Shell, Exxon, or BP 93 vs local or convenient store 93. I honestly think the damn dealership I bought it from filled it up with 87 and that’s why I saw the p0420.