Had my Mini since Nov... been using the premium fuel as suggested... MPG around 32 city/highway... tank before last I accidently put in Mid range fuel (you know the middle grade) mostly highway - ran fine got 37.5... this las time I was at Costco - waited in line - my turn - all they had was regulay - "what the hell" filled it up - agian mostly highway - at the last two red bars - not fueled up as yet to verify MPG - but looks again to be in the Mid 30's and it ran fine... So,,,,, whats up???? owners manual says to only put premium fuel - Keep in mind I have a Cooper NOT an "S"...


Note = I do understan - my speedometer is running slightly fast - meaning when it shows 60 - really doing about 57 - So, the math for MPG will also be off slightly.... This "error" is common in ALL Mini's

 

Firstly, lots of things can affect the speedo. It's not perfect in any car, which is why you get the +/- 5mph leeway from most police officers.

As far as fuel goes, some folks run regular and mid grade, or mix it, or some other combo thereof. This is not a good idea. They require premium in the car because of the compression ratio of the engine. The timing can adjust itself to counter knocks and pings introduced by pre-combustion and detonation, but it can only go so far. After a while, you will start to damage the engine...

FWIW - my car has only ever run premium, from one station, which is a top tier station...

 

+1

I agree with the premium...its only the difference of a dollar or 2 per tank and its worth the piece of mind

Also, minus what was in it upon delivery, I have only used Mobil 1 93 octane, and am going to use their oil as well I'm pleased with that company

 

Also, as an FYI:

http://www.toptiergas.com/

Some people disagree about this, and say that it's a marketing gimmick. However, if you visit the site, there are rigorous standards that must be adhered to, as well as conspicuous absence from some refiners that you would expect to find as a part of a marketing tactic...

Just my .02

 

I never understand why people will run regular octane when premium is clearly required. The difference in fill up price is like a dollar or two!! Stick to premium, your car and motor will thank you.

 

Another factor ethanol. I use premium (93) only but I noticed my MPG went down significantly when I filled up with a brand that had a percentage of it in the fuel.

 

Your math is a bit off The average price of regular in the US today is $3.59/gal. Average price of premium is $3.95/gal. Multiply both of those by 13 gallons and you get a difference of over seven dollars.

I'm not recommending using regular when premium is required, but the difference is definitely substantial, especially when calculated over the course of a year.

 

I think yours is off. 36 cents difference times 13 gallons is 4.68. My station is usually 30 cents higher than regular so it's 3.90. Some stations are only 20 cents more for premium and the difference would be 2.60. As gas and oil have skyrocketed the cost difference between premium and regular has gotten a little worse, from the usual 20 cents to 25 to 30. I use shell and its always 30 difference.

 

And if you want to add it up over a year...then multiply it time 5 years, or however long you keep your car...I'll guarantee it's still less than half of the cost of an engine rebuild.

 

No argument from me on that one, I always use premium.

 

Oh, I know...was just adding to your wisdom

 

Er, yeah my math was off But still, the difference is more than a buck or two.

 

If your car does't ping on regular, and you can tolerate the decreased performance, there is ABSOLUTLEY NO HARM being done to your engine. When you use regular, the knock sensors on your engine will retard the timing enough to avoid detonation (knock and ping). This WILL reduce engine performance but not necessarily fuel mileage (depending on your driving style). I routinely use 87 Octane since I drive 98% highway. My engine does not ping and I get 38-41 MPG using the OLD method of calculation, NOT the computer.

If you use regular and your car knocks and pings a lot, try mid grade. If that don't work, use Premium.

If you desire full engine performance 100% of the time... you'll need to use premium all the time. <cha-CHING$$$$$$>

 

This is completely false.

Running less than premium fuel in an engine with a compression ratio that calls for it is asking for engine problems. You can pit the piston crown, blow rings, and generally mangle the inside of your engine.

BMW/MINI doesn't call for premium because of some automaker/oil company conspiracy. They call for it because American fuel is crap.

 

+1 Think about this...When does the ECU retard the timing... WHEN IT STARTS TO PING. You don't notice it because the reaction is pretty fast, but believe me, it is happening. As a side note, the computer will gradually increase the timing and back it off again when it detects a ping, this happen quite frequently.

 

We have used only Premium grade (91) since we got our MCS. I do not mind spending a couple extra dollars per tank and not worry about how that regular stuff is slowly wreaking havoc in our MCS. If it improves reliability, I will use it. Nothing but the best for our MCS!!!

 

I will always run premium. I used mid-grade once and my mpg dropped to 27.5 mpg city, while I was getting 34.7 mpg city with premium, and I have tried this multiple times to make sure it wasn't a fluke. The car simply requires premium to run its best

 

Please show me your data. I guess the knock sensor controls on your car are a complete waste of money then? The engine damage you describe is caused by detonation. The knock sensor on your car detects detonation, retards the timing and in some control systems, even adjusts mixture, to PREVENT detonation. No detonation = no damage. The obvious trade-off is loss of power. If you can live with the decrease output or you spend most of your driving time at less than maximum HP (ie. highway driving), Then max output is not an huge issue for you and you can run lower octanes with NO ENGINE DAMAGE. If however, you enjoy the increased output or have a genuine need for higher power output some of the time (ie. City Driving), then by all means, buy premium.

No one is arguing that you need higher octane to achieve maximum performance. But I'd really like to see your proof that running lower than recommended octane in a modern engine with functional anti-detonation controls causes engine damage like you describe. If that's the case, I must be the luckiest SOB on the planet Earth since I've routinely run the following cars I've owned on 87 and 89 Octane for the listed numbers of miles WITHOUT DAMAGE. All of them had premium as the recommended fuel.

'06 GTI 2.0T (85 K miles, no engine damage)
'98 GTI VR6 (130 K miles, no engine damage, Did Solo racing, used premium for races)
'96 Audi A6 (120K miles, no engine damage)
'96 Audi A4 (80K, no damage, can't remember for sure if Prem. was recommended)

Here's a good place to start educating yourself on Octane.

http://en.wikipedia.org/wiki/Octane_rating

 

Firstly, you can take your elitist attitude and stick it. I don't need to "educate" myself, I'm quite certain my level of education surpasses yours, as well as a lot of people here.

Secondly, you list a ton of cars there...how many of them have you actually opened up and looked at? How many of them did you buy new? How many were used? You're just talking jibberish without any of this data.

Lastly, "where's my data"? Take your a$$ to google, and search. Find all of the hits - from huge publications, to the little state sites, that all cite how lower octane in an engine can damage pistons, valves, connecting rods, and so forth. This can happen from both pre-combustion, and detonation. Spend 10 minutes searching. I'd bet you change your mind. This is, of course, assuming you know how to search properly.

These engines were designed by engineers that know more about octane than you ever will, man. They are built to run at tolerances that require precise combustion. Once again, they don't tell you to run premium for fun. They do it because they don't want to have to repair your engine for you when you don't.

Have a problem with it? There's an American sh!tbox with your name on it.

/rant.

 

Wow. A profanity-laced diatribe. Nice.

I rest my case.

 

lmao. Profanity laced?

So, basically, you've nothing to retort, and you're going to be quiet. Sounds like a good move, jeeves

 

I think I've made my point. I'm still waiting on the mountians of data you have that proves that an engine with properly functioning detonation controls will blast itself into oblivion if run on lower than recommended octane fuels.

The cars I listed were all new, owned by me up to the stated miles, and driven about 90% of the time on either 87 or 89 octane. No, they weren't torn down to evaluate engine damage. There was no need too. There were no symptoms to suggest engine damage. SURELY, with all the horribly nasty and catastrophic consequenses of running low octane (as you suggest) all of those engines would have VAPORIZED by, oh say, 25K... right?

 

I totally agree with Krieg's assessments and requests. Too much ignorance going on in here. I'm still searching for significant evidence that 87 does any harm. This is an ongoing debate in various forums here at NAM. Regardless, MINI has printed that 87 will not damage their engines.
Greg

 

I run mid grade in my 7 and not one problem. Premium is overrated from what i have been reading on forums

 

WOW. If you only own the car for 2 or 3 years and sell before warranty, what does it matter? It doesn't. Answered for ya.